Provided by: gmic_1.7.9+zart-4build3_amd64 bug

NAME

       gmic   -   Perform  generic  image  processing  operations,  through  the  G'MIC  language
       interpreter.

HELP

         gmic: GREYC's Magic for Image Computing.

               Version 1.7.9, Copyright (c) 2008-2016, David Tschumperle.
               (http://gmic.eu)

        1. Usage
           -----

           gmic [-command1 [arg1_1,arg1_2,..]] .. [-commandN [argN_1,argN_2,..]]

           'gmic'  is  the  open-source  interpreter  of  the  G'MIC  language,  a   script-based
       programming
           language dedicated to the design of possibly complex image processing pipelines.
           It can be used to convert, manipulate, filter and visualize image datasets made of one
           or several 1d/2d or 3d multi-spectral images.

           This  reference  documentation  describes the rules and technical aspects of the G'MIC
       language.
           You   may   be   also   interested   by   our    detailed    tutorial    pages,    at:
       http://gmic.eu/tutorial/

        2. Overall context
           ---------------

         -  At  any  time,  G'MIC manages one list of numbered (and optionally named) pixel-based
       images,
            entirely stored (not compressed) in computer memory.

         - The first image of the list has indice '0' and is denoted by '[0]'. The  second  image
       of the
            list is denoted by '[1]', the third by '[2]' and so on.

         - Negative indices are treated in a periodic way: '[-1]' refers to the last image of the
       list,
            '[-2]' to the penultimate one, etc. Thus, if the list has 4 images, '[1]' and  '[-3]'
       both
            designate the second image of the list.

         -  A named image may be also indicated by '[name]', if 'name' uses the character set [a-
       zA-Z0-9_]
            and does not start with a number. Image names can be set or reassigned at any  moment
       during
            the processing pipeline (see commands '-name' and '-input' for this purpose).

         -  G'MIC  defines  a  set  of  various commands and substitution mechanisms to allow the
       design of
            complex pipelines managing this list of images, in a very flexible way:
            You can insert or remove images in the list, rearrange image indices, process images
            (individually or grouped), merge image data together, display and output image files,
       etc.

         - Such a pipeline can be written itself as a custom G'MIC command storable in a user
            command file, and can be re-used afterwards in another pipeline if necessary.

        3. Image definition and terminology
           --------------------------------

         -  In  G'MIC,  each  image  is  modeled  as  a  1d, 2d, 3d or 4d array of scalar values,
       uniformly
            discretized on a rectangular/parallelepipedic domain.

         - The four dimensions of this array are respectively denoted by:

           . 'width', the number of image columns (size along the 'x'-axis).
           . 'height', the number of image rows (size along the 'y'-axis).
           . 'depth', the number of image slices (size along the 'z'-axis).
               (the depth is equal to 1 for usual color or grayscale 2d images).
           . 'spectrum', the number of image channels (size along the 'c'-axis).
               (the spectrum is respectively equal to 3 and  4  for  usual  RGB  and  RGBA  color
       images).

         -  There  are  no  hard  limitations  on  the  size  the image along each dimension. For
       instance,
            the number of image slices or channels can be of arbitrary size within the limits of
            the available memory.

         - The width, height and depth of an image are considered as  spatial  dimensions,  while
       the
            spectrum has a multi-spectral meaning. Thus, a 4d image in G'MIC should be most often
            regarded  as  a  3d dataset of multi-spectral voxels. Most of the G'MIC commands will
       stick with
            this idea (e.g. command '-blur' blurs images only along the spatial 'xyz'-axes).

         - G'MIC stores all the image data as buffers of 'float' values (32 bits, value range
            [-3.4E38,+3.4E38]). It performs all its image  processing  operations  with  floating
       point
            numbers.  Each  image  pixel  takes  then  32bits/channel (except if double-precision
       buffers have
            been enabled during the compilation of the software, in which case 64bits/channel  is
       the
            default).

         -  Considering  'float'-valued  pixels  ensure  to  keep  the  numerical  precision when
       executing
            image processing pipelines. For  image  input/output  operations,  you  may  want  to
       prescribe the
            image datatype to be different than 'float' (like 'bool', 'char', 'int', etc...).
            This is possible by specifying it as a file option when using I/O commands.
            (see section 'Input/output properties' to learn more about file options).

        4. Items of a processing pipeline
           ------------------------------

         -  In  G'MIC, an image processing pipeline is described as a sequence of items separated
       by the
            space character ' '. Such items are interpreted and executed from  the  left  to  the
       right.
            For instance, the expression:

              filename.jpg -blur 3,0 -sharpen 10 -resize 200%,200% -output output.jpg

            defines a valid pipeline composed of nine G'MIC items.

         - Each G'MIC item is a string that is either a command, a list of command arguments,
            a filename, or a special input string.

         -  Escape  characters  '\'  and double quotes '"' can be used to define items containing
       spaces or
            other special characters. For instance, the two strings 'single\ item'  and  '"single
       item"'
            both define the same single item, with a space in it.

        5. Input data items
           ----------------

         -  If a specified G'MIC item appears to be an existing filename, the corresponding image
       data
            are loaded and inserted at the end of the image list (which is equivalent to the  use
       of
            '-input filename').

         -  Special  filenames  '-'  and  '-.ext'  stand  for  the standard input/output streams,
       optionally
            forced to be in a specific 'ext' file format (e.g. '-.jpg' or '-.png').

         - The following special input strings may be used as G'MIC items to  create  and  insert
       new
            images with prescribed values, at the end of the image list:

           . '[selection]' or '[selection]xN': Insert 1 or N copies of already existing images.
              'selection' may represent one or several images
              (see section 'Command items and selections' to learn more about selections).

           .   'width[%],_height[%],_depth[%],_spectrum[%],_values':  Insert  a  new  image  with
       specified
              size and values (adding '%' to a dimension means 'percentage of the size along  the
       same
              axis,  taken  from  the  last  image  '[-1]''). Any specified dimension can be also
       written as
              '[image]', and is then set to the size  (along  the  same  axis)  of  the  existing
       specified image
              [image]. 'values' can be either a sequence of numbers separated by commas ',', or a
              mathematical        expression,       as       e.g.       in       input       item
       '256,256,1,3,if(c==0,x,if(c==1,y,0))' which
              creates a 256x256 RGB color image with a spatial  shading  on  the  red  and  green
       channels.
              (see   section   'Mathematical   expressions'  to  learn  more  about  mathematical
       expressions).

           . '(v1,v2,..)': Insert a new image from specified prescribed values.  Value  separator
       inside
              parentheses  can  be  ','  (column  separator),  ';'  (row  separator),  '/' (slice
       separator) or
              '^' (channel separator). For instance, expression '(1,2,3;4,5,6;7,8,9)'  creates  a
       3x3 matrix
              (scalar image), with values running from 1 to 9.

           .  '0':  Insert  a  new 'empty' image, containing no pixel data. Empty images are used
       only in rare
              occasions.

         - Input item 'name=value' declares a new local or global variable 'name',  or  assign  a
       new value
            to  an  existing variable. Variable names must use the character set [a-zA-Z0-9_] and
       cannot
            start with a number.

         - A variable definition is always local to the current command except when it starts  by
       the
            underscore  character  '_'.  In  that case, it becomes also accessible by any command
       invoked
            outside the current command scope (global variable).

         - If a variable name starts with two underscores  '__',  the  global  variable  is  also
       shared among
            different  threads  and  can be read/set by commands running in parallel (see command
       '-parallel'
            for this purpose). Otherwise, it remains local to the thread that defined it.

         - Numerical variables can be updated with the use of these special operators:
           '+=' (addition), '-=' (subtraction),  '*='  (multiplication),  '/='  (division),  '%='
       (modulo),
           '&=' (bitwise and), '|=' (bitwise or), '^=' (power), '<<=' and '>>=' (bitwise left and
       right
           shifts). As in pipeline: 'foo=1 foo+=3'.

        6. Command items and selections
           ----------------------------

         - A G'MIC item starting by a  hyphen  '-'  designates  a  command,  most  of  the  time.
       Generally,
            commands  perform  image  processing operations on one or several available images of
       the list.

         - Reccurent commands have two  equivalent  names  (regular  and  short).  For  instance,
       command names
            '-resize' and '-r' refer to the same image resizing action.

         -  A  G'MIC  command may have mandatory or optional arguments. Command arguments must be
       specified
            in the next item on the command line.  Commas  ','  are  used  to  separate  multiple
       arguments of a
            single command, when required.

         - The execution of a G'MIC command may be restricted only to a subset of the image list,
       by
            appending  '[selection]'  to  the  command  name.  Examples  of  valid  syntaxes  for
       'selection' are:

           . '-command[-2]': Apply command only on the penultimate image [-2] of the list.
           . '-command[0,1,3]': Apply command only on images [0],[1] and [3].
           . '-command[3-6]': Apply command only on images [3] to [6] (i.e, [3],[4],[5] and [6]).
           . '-command[50%-100%]': Apply command only on the second half of the image list.
           . '-command[0,-4--1]': Apply command only on the first image and the last four images.
           . '-command[0-9:3]': Apply command only on images [0] to [9], with a step of 3
                                 (i.e. on images [0], [3], [6] and [9]).
           . '-command[0--1:2]': Apply command only on images of the list with even indices.
           .  '-command[0,2-4,50%--1]': Apply command on images [0],[2],[3],[4] and on the second
       half of
                                        the image list.
           . '-command[^0,1]': Apply command on all images except the two first.
           . '-command[name1,name2]': Apply command on named images 'name1' and 'name2'.

         - Indices in selections are always sorted in increasing order, and duplicate indices are
            discarded. For instance, selections '[3-1,1-3]' and '[1,1,1,3,2]' are both equivalent
       to
            '[1-3]'. If you want to repeat a single command multiple times on an image, use a
            '-repeat..-done'  loop  instead.  Inverting  the  order  of  images  for a command is
       achieved by
            explicitly  inverting   the  order  of  the  images  in  the   list,   with   command
       '-reverse[selection]'.

         - Command selections '[-1]','[-2]' and '[-3]' are so often used that they have their own
            shortcuts,  respectively  '.',  '..'  and  '...'.  For instance, command '-blur..' is
       equivalent to
            '-blur[-2]'. These shortcuts work also when specifying command arguments.

         - G'MIC commands invoked without '[selection]' are applied on all images  of  the  list,
       i.e. the
            default selection is '[0--1]' (except for command '-input' whose default selection is
       '[-1]').

         - A G'MIC command starting with a double hyphen '--' (instead of a  single  hyphen  '-')
       does not
            act  'in-place' but inserts its result as one or several new images at the end of the
       image
            list.

         - There are two different types of commands that can be run by the G'MIC interpreter:

           . Native commands, are the hard-coded functionalities in the  interpreter  core.  They
       are thus
              compiled  as  binary code and run fast, most of the time. Omitting an argument when
       invoking a
              native command is not  permitted,  except  if  all  following  arguments  are  also
       omitted.
              For instance, invoking '-plasma 10,,5' is invalid but '-plasma 10' is correct.
           .  Custom  commands, are defined as G'MIC pipelines of native or custom commands. They
       are
              interpreted by the G'MIC interpreter,  and  thus  run  a  bit  slower  than  native
       commands.
              Omitting  arguments  when  invoking  a  custom  command is permitted. For instance,
       expressions
              '-flower ,,,100,,2' or '-flower ,' are correct.

         - Most of the existing commands in G'MIC are actually defined as custom commands.

         - A user can easily add its own custom commands to the G'MIC interpreter (see section
            'Adding custom commands' for more details). New native commands cannot be added
            (unless you modify the G'MIC interpreter source code and recompile it).

        7. Input/output properties
           -----------------------

         - G'MIC is able to read/write most of the classical image file formats, including:

           . 2d grayscale/color files: .png, .jpeg, .gif, .pnm, .tif, .bmp, ...
           . 3d volumetric files: .dcm, .hdr, .nii, .pan, .inr, .pnk, ...
           . video files: .mpeg, .avi, .mov, .ogg, .flv, ...
           . Generic ascii or binary data files: .gmz, .cimg, .cimgz,  .dlm,  .asc,  .pfm,  .raw,
       .txt, .h.
           . 3d object files: .off.

         -  When dealing with color images, G'MIC generally reads, writes and displays data using
       the usual
            sRGB color space.

         - G'MIC is able to manage 3d objects that may be read from files or generated  by  G'MIC
       commands.
            A 3d object is stored as a one-column scalar image containing the object data, in the
            following order: { magic_number; sizes; vertices; primitives; colors; opacities }.
            These 3d representations can be then processed as regular images.
            (see command '-split3d' for accessing each of these 3d object data separately).

         -  Be  aware  that  usual  file  formats  may  be sometimes not adapted to store all the
       available image
            data, since G'MIC uses float-valued image buffers. For instance, saving an image that
       was
            initially loaded as a 16bits/channel image, as a .jpg file will result in a loss of
            information. Use the G'MIC-specific file extensions .cimgz or .gmz to ensure that all
       data
            precision are preserved when saving images.

         - Sometimes, file options may/must be set for file formats:

           . Video files: Only sub-frames of an image sequence may be  loaded,  using  the  input
       expression
              'filename.ext,[first_frame[,last_frame[,step]]]'.  Set  'last_frame==-1' to tell it
       must be
              the last frame of the video. Set 'step' to 0 to force an opened video file to be
              opened/closed. Output framerate and codec can be  also  set  by  using  the  output
       expression
              'filename.avi,_fps,_codec,_keep_open={ 0 | 1 }'. 'codec' is a 4-char string
              (see  http://www.fourcc.org/codecs.php)  or  '0' for the default codec. 'keep_open'
       tells if
              the output video file must be kept open for appending new frames afterwards.

           . .cimg[z] files: Only crops and sub-images of .cimg files can be  loaded,  using  the
       input
             expressions 'filename.cimg,N0,N1', 'filename.cimg,N0,N1,x0,x1',
             'filename.cimg,N0,N1,x0,y0,x1,y1', 'filename.cimg,N0,N1,x0,y0,z0,x1,y1,z1' or
             'filename.cimg,N0,N1,x0,y0,z0,c0,x1,y1,z1,c1'.
             Specifying  '-1'  for  one coordinates stands for the maximum possible value. Output
       expression
             'filename.cimg[z][,datatype]' can be used to force the output pixel type. 'datatype'
       can be
             { uchar | char | ushort | short | uint | int | uint64 | int64 | float | double }.

           .  .raw  binary  files:  Image  dimensions  and input pixel type may be specified when
       loading .raw
              files with input expresssion
              'filename.raw[,datatype][,width][,height[,depth[,dim[,offset]]]]]'.      If      no
       dimensions are
              specified, the resulting image is a one-column vector with maximum possible height.
       Pixel
              type can also be specified with the output expression 'filename.raw[,datatype]'.
              'datatype' can be the same as for .cimg[z] files.

           . .yuv files: Image dimensions must be specified, and  only  sub-frames  of  an  image
       sequence may
              be loaded, using the input expression
              'filename.yuv,width,height[,first_frame[,last_frame[,step]]]'.

           .  .tiff  files:  Only  sub-images  of multi-pages tiff files can be loaded, using the
       input
              expression 'filename.tif,_first_frame,_last_frame,_step'.
              Output                                                                   expression
       'filename.tiff,_datatype,_compression,_force_multipage,_use_bigtiff' can
              be used to specify the output pixel type, as well as the compression method.
              'datatype' can be the same as for .cimg[z] files. 'compression' can be
              {  none  (default) | lzw | jpeg }. 'force_multipage can be { 0=no (default) | 1=yes
       }.
              'use_bigtiff can be { 0=no | 1=yes (default) }.

           . .gif files: Animated gif files can be saved, using the input expression
              'filename.gif,fps>0,nb_loops'. Specify 'nb_loops=0' to get an  infinite  number  of
       animation
              loops (this is the default behavior).

           . .jpeg files: The output quality may be specified (in %), using the output expression
              'filename.jpg,30' (here, to get a 30% quality output). '100' is the default.

           . .mnc files: The output header can set from another file, using the output expression
              'filename.mnc,header_template.mnc'.

           .  .pan,  .cpp, .hpp, .c and .h files: The output datatype can be selected with output
       expression
              'filename[,datatype]'. 'datatype' can be the same as for .cimg[z] files.

           . .gmic files: These filenames are assumed to be G'MIC custom commands files.  Loading
       such a
              file will add the commands it defines to the interpreter. Debug information can be
              enabled/disabled  by  the  input  expression 'filename.gmic[,add_debug_info={ 0 | 1
       }]'.

           . Inserting 'ext:' on the beginning of a filename (e.g. 'jpg:filename')  forces  G'MIC
       to
              read/write  the  file  as it would have been done if it had the specified extension
       '.ext'.

         - Some input/output  formats  and  options  may  not  be  supported,  depending  on  the
       configuration
            flags that have been set during the build of the G'MIC software.

        8. Substitution rules
           ------------------

         - G'MIC items containing '$' or '{}' are substituted before being interpreted. Use these
            substituting expressions to access various data from the interpreter environment.

         -  '$name'  and  '${name}'  are  both  substituted  by  the value of the specified named
       variable
            (set previously by the item 'name=value'). If this variable has not been already set,
       the
            expression is substituted by the highest positive indice of the named image '[name]'.
       If no
            image has this name, the expression is substituted by the value of the OS environment
       variable
            with same name (it may be thus an empty string).
            The following reserved variables are predefined by the G'MIC interpreter:

              . '$!': The current number of images in the list.
              . '$>' and '$<': The increasing/decreasing indice of the latest (currently running)
                 'repeat...done' loop.
              . '$/': The current call stack. Stack items are separated by slashes '/'.
              . '$|': The current value (expressed in seconds) of a millisecond precision timer.
              . '$^': The current verbosity level.
              . '$_cpus': The number of computation cores available on your machine.
              . '$_pid': The current process identifier, as an integer.
              . '$_prerelease': For pre-releases only, the date of the pre-release as 'mmddyy'.
                 For stable releases, this variable is not defined.
              .  '$_version':  A  3-digits  number telling about the current version of the G'MIC
       interpreter
                 (currently '179').
              . '$_vt100': Set to 1 (default value) if colored text  output  is  allowed  on  the
       console.
              .  '$_path_rc':  The  path  to  the  G'MIC  folder  used  to  store  resources  and
       configuration files
                (its value is OS-dependent).
              . '$_path_user': The path to the G'MIC user file .gmic or user.gmic (its value is
                 OS-dependent).

         - '${"command line"}' is substituted by the status value set by  the  execution  of  the
       specified
            command  line  (see  command  '-status' to learn more about status). Expression '${}'
       thus stands
            for the current status value.

         - '{``string}' (starting with two backquotes) is substituted by a double-quoted  version
       of the
            specified string.

         - '{/string}' is substituted by the escaped version of the specified string.

         -  '{'string'}'  (between  single  quotes) is substituted by the sequence of ascii codes
       that compose
            the specified string, separated by  commas  ','.  For  instance,  item  '{'foo'}'  is
       substituted
            by '102,111,111'.

         -  '{image,feature}'  is substituted by a specific feature of the image [image]. 'image'
       can be
            either an image number or an image name. It can be also eluded, in  which  case,  the
       last image
            '[-1]' of the list is considered for the requested feature.
            Specified 'feature' can be one of:

              . 'b': The image basename (i.e. filename without the folder path nor extension).
              . 'f': The image folder name.
              . 'n': The image name or filename (if the image has been read from a file).
              . 't': The text string from the image values regarded as ascii codes.
              .  'x':  The  image  extension (i.e last characters after the last '.' in the image
       name).
              . '^ : The sequence of all image values, separated by commas ','.
              . '@subset': The sequence of image values corresponding to  the  specified  subset,
       and
                 separated by commas ','.
              .  Any other 'feature' is considered as a mathematical expression associated to the
       image
                 [image] and is substituted by the result of its evaluation  (float  value).  For
       instance,
                 expression  '{0,w+h}'  is  substituted by the sum of the width and height of the
       first image
                 (see section 'Mathematical expressions' for more  details).  If  a  mathematical
       expression
                 starts  with  an  underscore '_', the resulting value is truncated to a readable
       format.
                 For instance,  item  '{_pi}'  is  substituted  by  '3.14159'  (while  '{pi}'  is
       substituted by
                 '3.141592653589793').
              .  A  'feature'  delimited  by backquotes is replaced by a string whose ascii codes
       correspond
                 to  the  list  of  values  resulting  from  the  evaluation  of  the   specified
       mathematical
                 expression.  For  instance, item '{`[102,111,111]`}' is substituted by 'foo' and
       item
                 '{`vector8(65)`}' by 'AAAAAAAA'.

         - '{*}' is substituted by the visibility state of the instant display window [0] (can be
            { 0=closed | 1=visible }).

         - '{*,feature}' or '{*indice,feature}' is substituted  by  a  specific  feature  of  the
       instant
            display window #0 (or #indice, if specified). Requested 'feature' can be:

              . 'w': display width (i.e. width of the display area managed by the window).
              . 'h': display height (i.e. height of the display area managed by the window).
              . 'wh': display width x display height.
              . 'd': window width (i.e. width of the window widget).
              . 'e': window height (i.e. height of the window widget).
              . 'de': window width x window height.
              . 'u': screen width (actually independent on the window size).
              .' v': screen height (actually independent on the window size).
              . 'uv': screen width x screen height.
              . 'n': current normalization type of the instant display.
              . 't': window title of the instant display.
              . 'x': X-coordinate of the mouse position (or -1, if outside the display area).
              . 'y': Y-coordinate of the mouse position (or -1, if outside the display area).
              . 'b': state of the mouse buttons { 1=left-but. | 2=right-but. | 4=middle-but. }.
              . 'o': state of the mouse wheel.
              . 'k': decimal code of the pressed key if any, 0 otherwise.
              . 'c': boolean (0 or 1) telling if the instant display has been closed recently.
              . 'r': boolean telling if the instant display has been resized recently.
              . 'm': boolean telling if the instant display has been moved recently.
              .  Any  other  'feature'  stands  for  a  keycode name (in capital letters), and is
       substituted by
                 a boolean describing the current key state { 0=pressed | 1=released }.
              . You can also prepend a hyphen '-' to a 'feature' (that supports it) to flush the
                 corresponding event immediately after reading its state (works for  keys,  mouse
       and
                 window events).

         -  Item  substitution  is never performed in items between double quotes. One must break
       the quotes
           to enable substitution if needed, as in "3+8 kg = "{3+8}" kg". Using double quotes  is
       then
           a convenient way to disable the substitutions mechanism in items, when necessary.

         -  One  can  also  disable the substitution mechanism on items outside double quotes, by
       escaping the
            '{','}' or '$' characters, as in '\{3+4\}\ doesn't\ evaluate'.

        9. Mathematical expressions
           ------------------------

         - G'MIC has an embedded mathematical parser. It is used to evaluate  expressions  inside
       braces
            '{}', or formulas in commands that may take one as an argument (e.g. '-fill').

         -  When  the  context  allows  it, a formula is evaluated for each pixel of the selected
       images
            (e.g. '-fill').

         - A math expression may return a scalar or vector-valued result (with a fixed number of
            components).

         - The mathematical parser understands the following  set  of  functions,  operators  and
       variables:

           _ Usual operators: || (logical or), && (logical and), | (bitwise or), & (bitwise and),
              !=,  ==,  <=, >=, <, >, << (left bitwise shift), >> (right bitwise shift), -, +, *,
       /,
              % (modulo), ^ (power), ! (logical not), ~ (bitwise not),
              ++, --, +=, -=, *=, /=, %=, &=, |=, ^=, >>=, <<= (in-place operators).

           _ Usual math functions: abs(), acos(),  arg(),  argmax(),  argmin(),  asin(),  atan(),
       atan2(),
              cbrt(),  cos(),  cosh(),  cut(),  exp(),  fact(),  fibo(), gauss(), int(), isval(),
       isnan(),
              isinf(), isint(),  isbool(),  isfile(),  isdir(),  isin(),  kth(),  log(),  log2(),
       log10(),
              max(), mean(), med(), min(), narg(), prod(), rol() (left bit rotation),
              ror() (right bit rotation), round(), sign(), sin(), sinc(), sinh(), sqrt(), std(),
              sum(), tan(), tanh(), variance(), xor().

              .  'atan2(x,y)'  is  the  version of 'atan()' with two arguments 'y' and 'x' (as in
       C/C++).
              . 'permut(k,n,with_order)' computes the number of permutations of k objects from  a
       set of
                 n objects.
              . 'gauss(x,_sigma)' returns 'exp(-x^2/(2*s^2))/sqrt(2*pi*sigma^2)'.
              .  'cut(value,min,max)'  returns  value  if it is in range [min,max], or min or max
       otherwise.
              . 'narg(a_1,...,a_N)' returns the number of specified arguments (here, N).
              . 'arg(i,a_1,..,a_N)' returns the ith argument a_i.
              . 'isval()', 'isnan()', 'isinf()', 'isint()', 'isbool()' test the type of the given
                 number or expression, and return 0 (false) or 1 (true).
              . 'isfile()' (resp. 'isdir()') returns 0 (false) or 1 (true) whether  its  argument
       is a
                 path to an existing file (resp. to a directory) or not.
              .  'isin(v,a_1,...,a_n)'  returns 0 (false) or 1 (true) whether the first value 'v'
       appears
                 in the set of other values 'a_i'.
              . 'argmin()', 'argmax()', 'kth()', 'max()', 'mean()',  'med()',  'min()',  'std()',
       'sum()'
                 and  'variance()'  can  be  called  with  an  arbitrary  number of scalar/vector
       arguments.
              . 'round(value,rounding_value,direction)' returns a rounded value. 'direction'  can
       be
                 { -1=to-lowest | 0=to-nearest | 1=to-highest }.

           _ Variable names below are pre-defined. They can be overrided.

              . 'l': length of the associated list of images, if any (0 otherwise).
              . 'w': width of the associated image, if any (0 otherwise).
              . 'h': height of the associated image, if any (0 otherwise).
              . 'd': depth of the associated image, if any (0 otherwise).
              . 's': spectrum of the associated image, if any (0 otherwise).
              . 'r': shared state of the associated image, if any (0 otherwise).
              . 'wh': shortcut for width x height.
              . 'whd': shortcut for width x height x depth.
              .  'whds':  shortcut  for  width x height x depth x spectrum (i.e. number of scalar
       values).
              . 'i': current processed pixel value (i.e.  value  located  at  (x,y,z,c))  in  the
       associated
                 image, if any (0 otherwise).
              .  'iN':  Nth  channel  value  of  current  processed  pixel (i.e. value located at
       (x,y,z,N)) in
                 the associated image, if any (0 otherwise). 'N' must  be  an  integer  in  range
       [0,9].
              . 'R','G','B' and 'A' are equivalent to 'i0', 'i1', 'i2' and 'i3' respectively.
              .  'im','iM','ia','iv','is','ip','ic':  Respectively  the minimum, maximum, average
       values,
                 variance, sum, product and median value of  the  associated  image,  if  any  (0
       otherwise).
              . 'xm','ym','zm','cm': The pixel coordinates of the minimum value in the associated
                 image, if any (0 otherwise).
              . 'xM','yM','zM','cM': The pixel coordinates of the maximum value in the associated
                 image, if any (0 otherwise).
              .  'I':  current  vector-valued  processed pixel in the associated image, if any (0
       otherwise).
                 The number of vector components is equal to the number of image channels
                 (e.g. I = [ R,G,B ] for a RGB image).
              . You may add '#ind' to any of the variable name above to retrieve the  information
       for any
                 numbered  image  [ind]  of the list (when this makes sense). For instance 'ia#0'
       denotes the
                 average value of the first image of the list).
              . 'x': current processed column of the associated image, if any (0 otherwise).
              . 'y': current processed row of the associated image, if any (0 otherwise).
              . 'z': current processed slice of the associated image, if any (0 otherwise).
              . 'c': current processed channel of the associated image, if any (0 otherwise).
              . 't': thread id when an expression is evaluated with multiple threads (0 means
                 'master thread').
              . 'e': value of e, i.e. 2.71828...
              . 'pi': value of pi, i.e. 3.1415926...
              . 'u': a random value between [0,1], following a uniform distribution.
              . 'g': a random value, following a gaussian distribution of variance 1
                 (roughly in [-6,6]).
              . 'interpolation': value of the default interpolation mode used when reading  pixel
       values
                  with  the  pixel  access operators (i.e. when the interpolation argument is not
       explicitly
                  specified, see below for more details on pixel access operators).  Its  initial
       default
                  value is 0.
              .  'boundary':  value  of  the  default boundary conditions used when reading pixel
       values with
                  the pixel access operators (i.e. when the boundary condition  argument  is  not
       explicitly
                  specified,  see  below for more details on pixel access operators). Its initial
       default
                  value is 0.

           _ Vector calculus: Most operators are also able to work with vector-valued elements.

              . '[ a0,a1,...,aN ]' defines a (N+1)-dimensional vector  with  scalar  coefficients
       ak.
              .  'vectorN(a0,a1,,...,)' does the same, with the ak being repeated periodically if
       only a
                 few are specified.
              .  In  both  previous  expressions,  the  ak  can  be  vectors  themselves,  to  be
       concatenated into a
                 single vector.
              . The scalar element ak of a vector X is retrieved by 'X[k]'.
              .  The  sub-vector  [  X[p]...X[p+q-1]  ] (of size q) of a vector X is retrieved by
       'X[p,q]'.
              . Equality/inequality comparisons between two vectors is done with  operators  '=='
       and '!='.
              . Some vector-specific functions can be used on vector values:
                'cross(X,Y)'   (cross  product),  'dot(X,Y)'  (dot  product),  'size(X)'  (vector
       dimension),
                'sort(X,_is_increasing,_chunk_size)'  (sorting  values),  'reverse(A)'   (reverse
       order of
                components) and 'same(A,B,_nb_vals,_is_case_sensitive)' (vector equality test).
              .  Function  'resize(A,size,_interpolation,_boundary_conditions)' returns a resized
       version of
                 a vector 'A' with specified interpolation mode. 'interpolation' can be { -1=none
                 (memory content) | 0=none  |  1=nearest  |  2=average  |  3=linear  |  4=grid  |
       5=bicubic |
                 6=lanczos  },  and  'boundary_conditions'   can  be  { 0=dirichlet | 1=neumann |
       2=periodic }.
              . Function 'find(A,B,_is_forward,_starting_indice)' returns the  index  where  sub-
       vector B
                 appears  in  vector  A,  (or  -1 if B is not found in A). Argument A can be also
       replaced by
                 an image indice #ind.
              . A 2-dimensional vector may be  seen  as  a  complex  number  and  used  in  those
       particular
                 functions/operators:
                 '**'   (complex   multiplication),   '//'   (complex  division),  '^^'  (complex
       exponentiation),
                 '**='  (complex  self-multiplication),  '//='  (complex  self-division),   '^^='
       (complex
                 self-exponentiation),  'cabs()'  (complex modulus), 'carg()' (complex argument),
       'cconj()'
                 (complex  conjugate),  'cexp()'  (complex  exponential)  and  'clog()'  (complex
       logarithm).
              .  A  MN-dimensional  vector  may  be  seen  as  a  M  x N matrix and used in those
       particular
                 functions/operators:
                 '**' (matrix-vector multiplication), 'det(A)' (determinant), 'diag(V)' (diagonal
       matrix
                 from  a  vector),  'eig(A)' (eigenvalues/eigenvectors), 'eye(n)' (n x n identity
       matrix),
                 'inv(A)' (matrix inverse), 'mul(A,B,_nb_colsB)' (matrix-matrix multiplication),
                 'pseudoinv(A,_nb_colsA)', 'rot(x,y,z,angle)' (3d rotation matrix),  'rot(angle)'
       (2d
                 rotation  matrix),  'solve(A,B,_nb_colsB)' (least-square solver of linear system
       A.X = B),
                 'svd(A,_nb_colsA)' (singular value decomposition), 'trace(A)' (matrix trace) and
                 'transp(A,nb_colsA)' (matrix transpose). Argument 'nb_colsB' may be  omitted  if
       it is
                 equal to 1.
              .  Specifying  a  vector-valued  math  expression  as an argument of a command that
       operates on
                 image values (e.g. '-fill') modifies the whole spectrum range of  the  processed
       image(s),
                 for  each spatial coordinates (x,y,z). The command does not loop over the C-axis
       in this
                 case.

           _ String manipulation: Character strings are defined and managed as vectors objects.
              Dedicated functions and initializers to manage strings are

              . [ 'string' ] and 'string' define a vector whose values are the ascii codes of the
                 specified character string (e.g. 'foo' is equal to [ 102,111,111 ]).
              . _'character' returns the (scalar) ascii code of  the  specified  character  (e.g.
       _'A' is
                 equal to 65).
              .  A  special case happens for empty strings: Values of both expressions [ '' ] and
       '' are 0.
              .  Functions  'lowercase()'  and  'uppercase()'  return  string  with  all   string
       characters
                 lowercased or uppercased.
              .  Function  'stod(str,is_strict)'  parses  specified  string 'str' and returns the
       value
                 contained in it.

           _ Special operators can be used:

              . ';': expression separator. The returned value  is  always  the  last  encountered
       expression.
                 For instance expression '1;2;pi' is evaluated as 'pi'.
              .  '=':  variable  assignment.  Variables  in mathematical parser can only refer to
       numerical
                 values (vectors  or  scalars).  Variable  names  are  case-sensitive.  Use  this
       operator in
                 conjunction with ';' to define more complex evaluable expressions, such as
                 't=cos(x);3*t^2+2*t+1'.
                 These  variables  remain local to the mathematical parser and cannot be accessed
       outside
                  the evaluated expression.
              . Variables defined in math parser may have  a  constant  property,  by  specifying
       keyword const
                 before  the  variable  name  (e.g.  const  foo = pi/4;). The value set to such a
       variable must
                 be indeed  a  constant  scalar.  Constant  variables  allows  certain  types  of
       optimizations in
                 the math JIT compiler.

           _ The following specific functions are also defined:

              . 'normP(u1,...,un)' computes the LP-norm of the specified vector
                 (P being an unsigned integer constant or 'inf'). If P is omitted, the L2 norm is
       used.
              . 'u(max)' or 'u(min,max)': return a random value  between  [0,max]  or  [min,max],
       following
                 a uniform distribution.
              .  'i(_a,_b,_c,_d,_interpolation_type,_boundary_conditions)':  return  the value of
       the pixel
                 located at position (a,b,c,d) in the associated image, if any (0 otherwise).
                 'interpolation_type' can be { 0=nearest neighbor | other=linear }.
                 'boundary_conditions' can be { 0=dirichlet | 1=neumann | 2=periodic }.
                 Omitted coordinates are replaced by their default values which are respectively
                 x, y, z, c, interpolation and boundary.
                 For instance command '-fill 0.5*(i(x+1)-i(x-1))' will estimate the  X-derivative
       of an
                 image with a classical finite difference scheme.
              .  'j(_dx,_dy,_dz,_dc,_interpolation_type,_boundary_conditions)'  does the same for
       the pixel
                 located at position (x+dx,y+dy,z+dz,c+dc) (pixel access relative to the current
                 coordinates).
              . 'i[offset,_boundary_conditions]' returns  the  value  of  the  pixel  located  at
       specified
                 'offset' in the associated image buffer (or 0 if offset is out-of-bounds).
              .  'j[offset,_boundary_conditions]'  does  the  same  for an offset relative to the
       current pixel
                 coordinates (x,y,z,c).
              . 'i(#ind,_x,_y,_z,_c,_interpolation,_boundary)',
                 'j(#ind,_dx,_dy,_dz,_dc,_interpolation,_boundary)',
                 'i[#ind,offset,_boundary]' and  'i[offset,_boundary]'  are  similar  expressions
       used to
                 access pixel values for any numbered image [ind] of the list.
              .                       'I/J[offset,_boundary_conditions]'                      and
       'I/J(#ind,_x,_y,_z,_interpolation,_boundary)' do
                 the same as 'i/j[offset,_boundary_conditions]' and
                 'i/j(#ind,_x,_y,_z,_c,_interpolation,_boundary)' but return a vector instead  of
       a scalar
                 (e.g. a vector [ R,G,B ] for a pixel at (a,b,c) in a color image).
              . 'crop(_#ind,_x,_y,_z,_c,_dx,_dy,_dz,_dc,_boundary)' returns a vector whose values
       come
                 from the cropped region of image [ind] (or from default image selected if  'ind'
       is not
                 specified). Cropped region starts from point (x,y,z,c) and has a size of
                 dx  x  dy  x dz x dc. Arguments for coordinates and sizes can be omitted if they
       are not
                 ambiguous (e.g. 'crop(#ind,x,y,dx,dy)' is a valid invokation of this function).
              . 'draw(_#ind,S,x,y,z,c,dx,_dy,_dz,_dc,_opacity,_M,_max_M)' draws  a  sprite  S  in
       image [ind]
                 (or  in  default  image  selected  if  'ind'  is  not  specified) at coordinates
       (x,y,z,c).
                 The size of the sprite dx x dy x dz x dc must be specified. You can also specify
       a
                 corresponding opacity mask M if its size matches S.
              . 'if(condition,expr_then,_expr_else)': return value of 'expr_then' or 'expr_else',
                 depending  on the value of 'condition' (0=false, other=true). 'expr_else' can be
       omitted
                 in which case 0 is returned if the condition does not hold.  Using  the  ternary
       operator
                 'condition?expr_then[:expr_else]' gives an equivalent expression.
                 For  instance,  G'MIC  commands '-fill if(x%10==0,255,i)' and '-fill x%10?i:255'
       both draw
                 blank vertical lines on every 10th column of an image.
              . 'dowhile(expression,_condition)' repeats the  evaluation  of  'expression'  until
       'condition'
                 vanishes  (or  until  'expression' vanishes if no 'condition' is specified). For
       instance,
                 the expression:  'if(N<2,N,n=N-1;F0=0;F1=1;dowhile(F2=F0+F1;F0=F1;F1=F2,n=n-1))'
       returns
                 the Nth value of the Fibonacci sequence, for N>=0 (e.g., 46368 for N=24).
                 'dowhile(expression,condition)'  always  evaluates  the  specified expression at
       least once,
                 then check for the loop condition. When done,  it  returns  the  last  value  of
       'expression'.
              . 'for(init,condition,_procedure,body)' first evaluates the expression 'init', then
                 iteratively  evaluates  'body'  (followed  by  'procedure'  if  specified) while
       'condition'
                 is verified (i.e. not zero). It may happen that no iteration is done,  in  which
       case the
                 function returns nan. Otherwise, it returns the last value of 'body'.
                 For                  instance,                  the                  expression:
       'if(N<2,N,for(n=N;F0=0;F1=1,n=n-1,F2=F0+F1;F0=F1;F1=F2))'
                 returns the Nth value of the Fibonacci  sequence,  for  N>=0  (e.g.,  46368  for
       N=24).
              .      'whiledo(condition,expression)'      is      exactly     the     same     as
       'for(init,condition,expression)'
                 without the specification of an initializing expression.
              . 'break()' and 'continue()' respectively breaks and continues the current  running
       bloc
                 (loop, init or main environment).
              .  'date(attr,path)'  returns  the  date  attribute  for  the given 'path' (file or
       directory),
                 with 'attr' being { 0=year | 1=month | 2=day | 3=day of week | 4=hour | 5=minute
       |
                 6=second }.
              . 'date(_attr) returns the specified attribute for the current (locale) date.
              .  'print(expr1,expr2,...)  prints  the  value  of the specified expressions on the
       console
                 (and returns the value of the last expression).
              . 'debug(expression) prints  detailed  debug  information  about  the  sequence  of
       operations done
                 by the math parser to evaluate the expression (and returns its value).
              .  'display(_X)  prints  and displays the contents of the specified vector 'X', and
       wait for
                 user events. if no arguments are provided, a memory snapshot of the math parser
                 environment is displayed instead.
              . 'init(expression)  evaluates  the  specified  expression  only  once,  even  when
       multiple
                 evaluations are required (e.g. in '-fill init(foo=0);++foo').
              .  'copy(dest,src,_nb_elts,_inc_d,_inc_s,_opacity) copies an entire memory block of
       'nb_elts'
                 elements starting from a source value 'src' to a specified  destination  'dest',
       with
                 increments  defined  by 'inc_d' and 'inc_s' respectively for the destination and
       source
                 pointers.
              . 'unref(a,b,...) destroys references to the named variable given as arguments.
              . 'breakpoint()  inserts  a  computation  breakpoint  (not  supported  by  the  cli
       interface).

           - User-defined macros:

              .  Custom macro functions can be defined in a math expression, using the assignment
       operator
                 '=', e.g. 'foo(x,y) = cos(x + y); result = foo(1,2) + foo(2,3)'.
              . Trying to override a built-in function (e.g. 'abs()') has no effect.
              . Overloading macros with different number of arguments is possible. Re-defining a
                 previously defined macro with the same number of arguments discards its previous
                 definition.
              . Macro functions are indeed processed as macros by the mathematical evaluator. You
       should
                 avoid invoking them with arguments that are themselves results of assignments or
                 self-operations.  For  instance,  'foo(x)  = x + x; z = 0; foo(++z)' returns '4'
       rather
                 than expected value '2'.
              . When substituted, macro arguments are placed  inside  parentheses,  except  if  a
       number sign
                 '#' is located just before or after the argument name. For instance, expression
                 'foo(x,y)  =  x*y;  foo(1+2,3)'  returns '9' (being substituted as '(1+2)*(3)'),
       while
                 expression 'foo(x,y) = x#*y#; foo(1+2,3)'  returns  '7'  (being  substituted  as
       '1+2*3').
              .  Number  signs  appearing  between  macro  arguments  function actually count for
       'empty'
                 separators. They may be used to force the substitution  of  macro  arguments  in
       unusual
                 places, e.g. as in 'str(N) = ['I like N#'];'.

           - Multi-threaded and in-place evaluation:

              .  If  your  image data are large enough and you have several CPUs available, it is
       likely that
                 the math expression passed to a '-fill' or  '-input'  command  is  evaluated  in
       parallel,
                 using multiple computation threads.
              .  Starting  an  expression  with ':' or '*' forces the evaluations required for an
       image to be
                 run in parallel, even if the amount of data to process is small (beware, it  may
       be slower
                 to evaluate in this case!). Specify ':' (instead of '*') to avoid possible image
       copy
                 done before evaluating the expression (this saves memory, but do  this  only  if
       you are
                 sure this step is not required!)
              . If the specified expression starts with '>' or '<', the pixel access operators
                 'i(), i[], j()' and 'j[]' return values of the image being currently modified,
                 in forward ('>') or backward ('<') order. The multi-threading evaluation of the
                 expression is also disabled in this case.
              .  Function  '(operands)'  forces  the  execution of the given operands in a single
       thread at a
                 time.

           _      Expressions      'i(_#ind,x,_y,_z,_c)=value',      'j(_#ind,x,_y,_z,_c)=value',
       'i[_#ind,offset]=value'
              and  'j[_#ind,offset]=value'  set  a  pixel  value at a different location than the
       running one
              in the image [ind] (or in the associated image  if  argument  '#ind'  is  omitted),
       either with
              global  coordinates/offsets  (with  'i(...)'  and  'i[...]'),  or relatively to the
       current
              position (x,y,z,c) (with 'j(...)' and 'j[...]'). These  expressions  always  return
       'value'.

         - The last image of the list is always associated to the evaluations of '{expressions}',
            e.g.  G'MIC  sequence  '256,128 -f {w}' will create a 256x128 image filled with value
       256.

        10. Image and data viewers
            ----------------------

         - G'MIC has some very handy embedded visualization  modules,  for  1d  signals  (command
       '-plot'),
            1d/2d/3d  images  (command  '-display')  and  3d  objects  (command '-display3d'). It
       manages
            interactive views of the selected image data.

         - The following keyboard shortcuts are available in the interactive viewers:

           . (mousewheel): Zoom in/out.
           . CTRL+D: Increase window size.
           . CTRL+C: Decrease window size.
           . CTRL+R: Reset window size.
           . CTRL+W: Close window.
           . CTRL+F: Toggle fullscreen mode.
           . CTRL+S: Save current window snapshot as numbered file 'gmic_xxxx.bmp'.
           .  CTRL+O:  Save  current  instance   of   the   viewed   data,   as   numbered   file
       'gmic_xxxx.cimgz'.

         - Shortcuts specific to the 1d/2d/3d image viewer (command '-display') are:

           . CTRL+A: Switch cursor mode.
           . CTRL+P: Play z-stack of frames as a movie (for volumetric 3d images).
           . CTRL+V: Show/hide 3D view (for volumetric 3d images).
           . CTRL+(mousewheel): Go up/down.
           . SHIFT+(mousewheel): Go left/right.
           . Numeric PAD: Zoom in/out (+/-) and move through zoomed image (digits).
           . BACKSPACE: Reset zoom scale.

         - Shortcuts specific to the 3d object viewer (command '-display3d') are:

           . (mouse)+(left mouse button): Rotate 3d object.
           . (mouse)+(right mouse button): Zoom 3d object.
           . (mouse)+(middle mouse button): Shift 3d object.
           . CTRL+F1 ... CTRL+F6: Toggle between different 3d rendering modes.
           . CTRL+Z: Enable/disable z-buffered rendering.
           . CTRL+A: Show/hide 3d axes.
           . CTRL+G: Save 3d object, as numbered file 'gmic_xxxx.off'.
           . CTRL+T: Switch between single/double-sided 3d modes.

        11. Adding custom commands
            ----------------------

         - New custom commands can be added by the user, through the use of G'MIC custom commands
       files.

         - A command file is a simple ascii text file, where each line starts either by
            'command_name: command_definition' or 'command_definition (continuation)'.

         - At startup, G'MIC automatically includes user's command file $HOME/.gmic (on Unix) or
            %APPDATA%/user.gmic (on Windows). The CLI tool 'gmic' automatically runs the command
            '-cli_start' if defined.

         - Custom command names must use character set  [a-zA-Z0-9_]  and  cannot  start  with  a
       number.

         -  Any ' # comment' expression found in a custom commands file is discarded by the G'MIC
       parser,
            wherever it is located in a line.

         - In a custom command, the following $-expressions are recognized and substituted:

           . '$*' is substituted by a copy of the specified string of arguments.
           . '$"*"' is substituted by a copy of the specified string of arguments, each being
              double-quoted.
           . '$#' is substituted by the maximum indice of known arguments  (either  specified  by
       the user
              or set to a default value in the custom command).
           .  '$?'  is substituted by a string telling about the command subset restriction (only
       useful
              when custom commands need to output descriptive messages).
           . '$i' and '${i}' are both  substituted  by  the  i^th  specified  argument.  Negative
       indices such as
              '${-j}'  are  allowed and refer to the j^th latest argument. '$0' is substituted by
       the
              custom command name.
           . '${i=default}' is substituted by the value of $i (if defined) or by  its  new  value
       set to
               'default' otherwise ('default' may be a $-expression as well).
           .  '${subset}'  is  substituted  by the argument values (separated by commas ',') of a
       specified
              argument subset. For instance expression '${2--2}' is substitued by  all  specified
       command
              arguments except the first and the last one. Expression '${^0}' is then substituted
       by all
              arguments of the invoked command (eq. to  '$*'  if  all  specified  arguments  have
       indeed a
              value).
           .  '$=var' is substituted by the set of instructions that will assign each argument $i
       to the
              named variable 'var$i' (for i in [0...$#]). This  is  particularly  useful  when  a
       custom
              command  want  to  manage  variable  numbers of arguments. Variables names must use
       character set
              [a-zA-Z0-9_] and cannot start with a number.

         - These particular $-expressions for custom commands are always substituted, even in
            double-quoted items or when the dollar sign '$' is escaped with a backslash  '\'.  To
       avoid
            substitution, place an empty double quoted string just after the '$' (as in '$""1').

         -  Specifying arguments may be skipped when invoking a custom command, by replacing them
       by commas
            ',' as in expression '-flower ,,3'.  Omitted  arguments  are  set  to  their  default
       values, which
            must  be  thus  explicitly  defined  in  the code of the corresponding custom command
       (using
            default argument expressions as '${1=default}').

         - If one numbered argument required by a custom command misses  a  value,  an  error  is
       thrown by the
            G'MIC interpreter.

        12. List of commands
            ----------------

          All  available  G'MIC  commands  are  listed  below, classified by themes. When several
       choices of
          command arguments are possible, they appear separated by  '|'.  An  argument  specified
       inside '[]'
          or  starting  by  '_'  is  optional except when standing for an existing image [image],
       where 'image'
          can be either an indice number or an image name. In this case, the '[]' characters  are
       mandatory
          when  writing the item. A command marked with '(+)' is one of the native commands. Note
       also that
          all images that serve as illustrations in this reference documentation  are  normalized
       in [0,255]
          before being displayed. You may need to do this explicitly (command '-normalize 0,255')
       if you
          want to save and view images with the same aspect than those illustrated in the example
       codes.

        ** Global options:

           -debug (+):

               Activate debug mode.
               When activated, the G'MIC interpreter becomes very verbose and outputs additionnal
       log
               messages about its internal state on the standard output (stdout).
               This  option  is  useful  for  developers  or  to  report  possible  bugs  of  the
       interpreter.

           -help:
                               command |
                               (no arg)

               Display help (optionally for specified command only) and exit.
               (eq. to '-h').

           -version:

               Display current version number on stdout.

        ** Input/output:

           -camera (+):
                               _camera_index>=0,_nb_frames>0,_skip_frames>=0,_capture_width>=0,
                                 _capture_height>=0

               Insert one or several frames from specified camera.
               When  'nb_frames==0',  the  camera  stream  is  released  instead of capturing new
       images.
               Default values: 'camera_index=0' (default camera), 'nb_frames=1',  'skip_frames=0'
       and
                 'capture_width=capture_height=0' (default size).

           -clut:
                               "clut_name",_resolution>0

               Insert one of the pre-defined CLUT at the end of the image list.

           -command (+):
                               _add_debug_info={ 0 | 1 },{ filename | http[s]://URL | "string" }

               Import G'MIC custom commands from specified file, URL or string.
               (eq. to '-m').
               Imported commands are available directly after the '-command' invocation.
               Default value: 'add_debug_info=1'.

           -cursor (+):
                               _mode = { 0=hide | 1=show }

               Show or hide mouse cursor for selected instant display windows.
               Command  selection  (if  any) stands for instant display window indices instead of
       image indices.
               Default value: 'mode=1'.

           -display (+):
                               _X>=0,_Y>=0,_Z>=0,_exit_on_anykey={ 0 | 1 }

               Display selected images in an interactive viewer (use the instant  display  window
       [0] if opened).
               (eq. to '-d').
               Arguments  'X','Y','Z'  determine  the  initial  selection view, for 3d volumetric
       images.
               Default value: 'X=Y=Z=0' and 'exit_on_anykey=0'.

           -display0:

               Display selected images without value normalization.
               (eq. to '-d0').

           -display3d (+):
                               _[background_image],_exit_on_anykey={ 0 | 1 } |
                               _exit_on_anykey={ 0 | 1 }

               Display selected 3d objects in an interactive  viewer  (use  the  instant  display
       window [0] if
                 opened).
               (eq. to '-d3d').
               Default values: '[background_image]=(default)' and 'exit_on_anykey=0'.

           -display_array:
                               _width>0,_height>0

               Display images in interactive windows where pixel neighborhoods can be explored.
               Default values: 'width=13' and 'height=width'.

           -display_fft:

               Display  fourier  transform  of  selected  images,  with  centered  log-module and
       argument.
               (eq. to '-dfft').

           -display_graph:
                               _width>32,_height>32,_plot_type,_vertex_type,_xmin,_xmax,_ymin,_ymax,_xlabel,
                                 _ylabel

               Render graph plot from selected image data.
               'plot_type' can be { 0=none | 1=lines | 2=splines | 3=bar }.
               'vertex_type' can be { 0=none | 1=points | 2,3=crosses | 4,5=circles | 6,7=squares
       }.
               'xmin','xmax','ymin','ymax' set the coordinates of the displayed xy-axes.
               Default values: 'width=640', 'height=480', 'plot_type=1', 'vertex_type=1',
                 'xmin=xmax=ymin=ymax=0 (auto)', 'xlabel="x-axis"' and 'ylabel="y-axis"'.

           -display_histogram:
                               _width>0,_height>0,_clusters>0,_min_value[%],_max_value[%],_show_axes={
       0 | 1 },
                                 _expression.

               Render a channel-by-channel histogram.
               If  selected  image  has  several slices, the rendering is performed for all input
       slices.
               'expression' is a mathematical expression used to transform the histogram data for
                 visualization purpose.
               (eq. to '-dh').
               Default  values:  'width=512',   'height=300',   'clusters=256',   'min_value=0%',
       'max_value=100%',
                 'show_axes=1' and 'expression=i'.

           -display_parametric:
                               _width>0,_height>0,_outline_opacity,_vertex_radius>=0,_is_antialiased={
       0 | 1 },
                                 _is_decorated={ 0 | 1 },_xlabel,_ylabel

               Render 2d or 3d parametric curve or point clouds from selected image data.
               Curve points are defined as pixels of a 2 or 3-channel image.
               If the point image contains more than 3 channels, additional channels  define  the
       (R,G,B) color
                 for each vertex.
               If  'outline_opacity>1',  the outline is colored according to the specified vertex
       colors and
                 'outline_opacity-1' is used
               as the actual drawing opacity.
               Default     values:     'width=512',     'height=width',      'outline_opacity=3',
       'vertex_radius=0',
                 'is_antialiased=1', 'is_decorated=1', 'xlabel="x-axis"' and 'ylabel="y-axis"'.

           -display_polar:
                               _width>32,_height>32,_outline_type,_fill_R,_fill_G,_fill_B,_theta_start,
                                 _theta_end,_xlabel,_ylabel

               Render polar curve from selected image data.
               (eq. to '-dp').
               'outline_type' can be { r<0=dots with radius -r | 0=no  outline  |  r>0=lines+dots
       with radius r }.
               'fill_color' can be { -1=no fill | R,G,B=fill with specified color }.
               Default      values:      'width=500',      'height=width',      'outline_type=1',
       'fill_R=fill_G=fill_B=200',
                 'theta_start=0', 'theta_end=360', 'xlabel="x-axis"' and 'ylabel="y-axis"'.

           -display_quiver:
                               _size_factor>0,_arrow_size>=0,_color_mode={     0=monochrome     |
       1=grayscale |
                                 2=color }

               Render selected image of 2d vectors as a field of 2d arrows.
               (eq. to '-dq').
               Default values: 'size_factor=16', 'arrow_size=1.5' and 'color_mode=1'.

           -display_rgba:

               Render selected RGBA images over a checkerboard background.
               (eq. to '-drgba').

           -display_tensors:
                               _size_factor>0,_ellipse_size>=0,_color_mode={    0=monochrome    |
       1=grayscale |
                                 2=color },_outline>=0

               Render selected image of tensors as a field of 2d ellipses.
               (eq. to '-dt').
               Default   values:   'size_factor=16',   'ellipse_size=1.5',   'color_mode=2'   and
       'outline=2'.

           -display_warp:
                               _cell_size>0

               Render selected 2d warping fields.
               (eq. to '-dw').
               Default value: 'cell_size=15'.

           -document_gmic:
                               _format={    ascii    |   bash   |   html   |   images   |   latex
       },_image_path,_write_wrapper={ 0
                                 | 1 }

               Create documentation of .gmic command files (loaded as  raw  'uchar'  images),  in
       specified format.
               Default values: 'format=ascii', 'image_path=""' and 'write_wrapper=1'.
               Example(s) : raw:filename.gmic,char -document_gmic html,img

           -echo (+):
                               message

               Output specified message on the error output.
               (eq. to '-e').
               Command selection (if any) stands for displayed call stack subset instead of image
       indices.

           -echo_file:
                               filename,message

               Output specified message, appending it to specified output file.
               (similar to '-echo' for specified output file stream).

           -echo_stdout:
                               message

               Output specified message, on the standard output (stdout).
               (similar to '-echo' for output on standard output instead of standard error).

           -function1d:
                               0<=smoothness<=1,x0>=0,y0,x1>=0,y1,...,xn>=0,yn

               Insert continuous 1d function from specified list of keypoints (xk,yk)
               in range [0,max(xk)] (xk are positive integers).
               Default values: 'smoothness=1' and 'x0=y0=0'.

           -gmicky:

               Insert new image of the G'MIC mascot 'Gmicky'.

           -gmicky_deevad:

               Insert new image of the G'MIC mascot 'Gmicky', by David Revoy.

           -gmicky_mahvin:

               Insert new image of the G'MIC mascot 'Gmicky', by Mahvin.

           -gmicky_wilber:

               Insert new image of the G'MIC mascot 'Gmicky' together with GIMP mascot  'Wilber',
       by Mahvin.

           -input (+):
                               [type:]filename |
                               [type:]http://URL |
                               [selection]x_nb_copies>0 |
                               {   width>0[%]  |  [image_w]  },{  _height>0[%]  |  [image_h]  },{
       _depth>0[%] |
                                 [image_d] },{ _spectrum>0[%] | [image_s] },_{ value1,_value2,...
       | 'formula' } |
                               (value1{,|;|/|^}value2{,|;|/|^}...) |
                               0

               Insert  a  new  image  taken  from  a filename or from a copy of an existing image
       ['indice'],"
               or insert new image with specified dimensions and values.  Single  quotes  may  be
       omitted in
               'formula'. Specifying argument '0' inserts an 'empty' image.
               (eq. to '-i' | (no arg)).
               Default values: 'nb_copies=1', 'height=depth=spectrum=1' and 'value1=0'.

           -input_cube:
                               "filename",_convert_1d_cluts_to_3d={ 0 | 1 }.

               Insert CLUT data from a .cube filename (Adobe CLUT format).
               Default value: 'convert_1d_cluts_to_3d=0'.

           -input_glob:
                               pattern

               Insert new images from several filenames that match the specified glob pattern.

           -input_gpl:
                               filename

               Input specified filename as a GIMP palette data file.

           -output (+):
                               [type:]filename,_format_options

               Output selected images as one or several numbered file(s).
               (eq. to '-o').
               Default value: 'format_options'=(undefined).

           -output_cube:
                               filename

               Output selected CLUTs as a .cube file (Adobe CLUT format).

           -output_ggr:
                               filename,_gradient_name

               Output selected images as GIMP gradient files.
               If no gradient name is specified, it is deduced from the filename.

           -outputn:
                               filename

               Output selected images as automatically numbered filenames in repeat...done loops.
               (eq. to '-on').

           -outputp:
                               prefix

               Output selected images as prefixed versions of their original filenames.
               (eq. to '-op').
               Default value: 'prefix=_'.

           -outputw:

               Output selected images by overwritting their original location.
               (eq. to '-ow').

           -outputx:
                               extension1,_extension2,_...,_extensionN,_output_at_same_location={
       0 | 1 }

               Output selected images with same base filenames but for N different extensions.
               (eq. to '-ox').
               Default value: 'output_at_same_location=0'.

           -pass (+):
                               _shared_state={ 0=non-shared (copy) | 1=shared | 2=adaptive }

               Insert images from parent context of a custom command or a local environment.
               Command selection (if any) stands for a selection of images in the parent context.
               By default (adaptive shared state), selected images are inserted in a shared state
       if they do
                 not  belong  to  the  context (selection) of the current custom command or local
       environment as
                 well.
               Typical use of command '-pass' concerns the design of custom  commands  that  take
       images as
                 arguments.
               Default value: 'shared_state=2'.

           -plot (+):
                               _plot_type,_vertex_type,_xmin,_xmax,_ymin,_ymax,_exit_on_anykey={
       0 | 1 } |
                               'formula',_resolution>=0,_plot_type,_vertex_type,_xmin,xmax,_ymin,_ymax,
                                 _exit_on_anykey={ 0 | 1 }

               Display  selected  image  or  formula  in  an  interactive viewer (use the instant
       display window [0]
                 if opened).
               'plot_type' can be { 0=none | 1=lines | 2=splines | 3=bar }.
               'vertex_type' can be { 0=none | 1=points | 2,3=crosses | 4,5=circles | 6,7=squares
       }.
               'xmin','xmax','ymin','ymax' set the coordinates of the displayed xy-axes.
               Default values: 'plot_type=1', 'vertex_type=1', 'xmin=xmax=ymin=ymax=0 (auto)' and
                 'exit_on_anykey=0'.

           -print (+):

               Output information on selected images, on the standard error (stderr).
               (eq. to '-p').

           -rainbow_lut:

               Input a 256-entries RGB colormap of rainbow colors.

           -roddy:

               Input a new image of the G'MIC Rodilius mascot 'Roddy'.

           -screen (+):
                               _x0[%],_y0[%],_x1[%],_y1[%]

               Take screenshot, optionally grabbed with specified coordinates, and insert it
               at the end of the image list.

           -select (+):
                               feature_type,_X,_Y,_Z,_exit_on_anykey={ 0 | 1 }

               Interactively  select  a  feature  from  selected  images (use the instant display
       window [0] if
                 opened).
               'feature_type' can be { 0=point | 1=segment | 2=rectangle | 3=ellipse }.
               Arguments 'X','Y','Z' determine the initial  selection  view,  for  3d  volumetric
       images.
               The retrieved feature is returned as a 3d vector (if 'feature_type==0') or as a 6d
       vector
               (if 'feature_type!=0') containing the feature coordinates.
               The coordinates of the last selected features are  also  returned  as  the  status
       value.
               Default values: 'X=Y=Z=(undefined)' and 'exit_on_anykey=0'.

           -serialize (+):
                               _datatype,_is_compressed={ 0 | 1 },_store_names={ 0 | 1 }

               Serialize selected list of images into a single image, optionnally in a compressed
       form.
               'datatype' can be { uchar | char | ushort | short | uint | int | uint64 | int64  |
       float |
                 double }.
               Specify  'datatype' if all selected images have a range of values constrained to a
       particular
                 datatype, in order to minimize the memory footprint.
               The resulting image has only integers values in [0,255] and can then be saved as a
       raw image of
               unsigned chars (doing so will output a valid .cimg[z] or .gmz file).
               If  'store_names'  is set to '1', serialization uses the .gmz format to store data
       in memory
                 (otherwise the .cimg[z] format).
               Default values: 'datatype=float', 'is_compressed=1' and 'store_names=1'.

           -shape_heart:
                               _size>=0

               Input a 2d heart binary shape with specified size.
               Default value: 'size=512'.

           -shape_circle:
                               _size>=0

               Input a 2d circle binary shape with specified size.
               Default value: 'size=512'.

           -shape_cupid:
                               _size>=0

               Input a 2d cupid binary shape with specified size.
               Default value: 'size=512'.

           -shape_diamond:
                               _size>=0

               Input a 2d diamond binary shape with specified size.
               Default value: 'size=512'.

           -shape_fern:
                               _size>=0,_density[%]>=0,_angle,0<=_opacity<=1,_type={ 0=Asplenium
                                 adiantum-nigrum | 1=Thelypteridaceae }

               Input a 2d Barnsley fern with specified size.
               Default value: 'size=512', 'density=50%', 'angle=30', 'opacity=0.3' and 'type=0'.

           -shape_polygon:
                               _size>=0,_nb_vertices>=3,_angle

               Input a 2d polygonal binary shape with specified geometry.
               Default value: 'size=512', 'nb_vertices=5' and 'angle=0'.

           -shape_snowflake:
                               size>=0,0<=_nb_recursions<=6

               Input a 2d snowflake binary shape with specified size.
               Default values: 'size=512' and 'nb_recursions=5'.

           -shape_star:
                               _size>=0,_nb_branches>0,0<=_thickness<=1

               Input a 2d star binary shape with specified size.
               Default values: 'size=512', 'nb_branches=5' and 'thickness=0.38'.

           -shared (+):
                               x0[%],x1[%],y[%],z[%],v[%] |
                               y0[%],y1[%],z[%],v[%] |
                               z0[%],z1[%],v[%] |
                               v0[%],v1[%] |
                               v0[%] |
                               (no arg)

               Insert shared buffers from (opt. points/rows/planes/channels of) selected images.
               Shared buffers cannot be returned by a command, nor a local environment.
               (eq. to '-sh').

           -sample:
                               _name={ ? | apples | barbara |  boats  |  bottles  |  butterfly  |
       cameraman | cat |
                                 cliff  |  duck  |  eagle  | elephant | earth | flower | fruits |
       greece | gummy |
                                 house | inside | landscape | leaf | lena |  lion  |  mandrill  |
       monkey | parrots |
                                 pencils  |  peppers  | rooster | rose | square | teddy | tiger |
       wall | waterfall |
                                  zelda },_width={ >=0 | 0 (auto) },_height = { >=0 | 0 (auto)  }
       |
                               (no arg)

               Input a new sample RGB image (opt. with specified size).
               (eq. to '-sp').
               Argument 'name' can be replaced by an integer which serves as a sample index.

           -srand (+):
                               value |
                               (no arg)

               Set random generator seed.
               If no argument is specified, a random value is used as the random generator seed.

           -string:
                               "string"

               Insert new image containing the ascii codes of specified string.

           -testimage2d:
                               _width>0,_height>0,_spectrum>0

               Input a 2d synthetic image.
               Default values: 'width=512', 'height=width' and 'spectrum=3'.

           -uncommand (+):
                               command_name[,_command_name2,...] |
                               *

               Discard last definition of specified custom commands.
               Set argument to '*' for discarding all existing custom commands.

           -uniform_distribution:
                               nb_levels>=1,spectrum>=1

               Input set of uniformly distributed N-d points in [0,1]^N.

           -unserialize (+):

               Recreate  lists  of  images  from  serialized image buffers, obtained with command
       '-serialize'.

           -update:

               Update commands from the latest definition file on the G'MIC server.
               This requires an active Internet connection and an access to the external
               tools 'curl' or 'wget'.
               Once the update has been downloaded, running 'gmic' makes it use automatically.
               (eq. to '-up').

           -verbose (+):
                               level |
                               { + | - }

               Set or increment/decrement the verbosity level. Default level is 0.
               (eq. to '-v').
               When 'level'>=0, G'MIC log messages are displayed on the standard error (stderr).
               Default value: 'level=0'.

           -wait (+):
                               delay |
                               (no arg)

               Wait for a given delay (in ms), optionally since the last call to '-wait'.
               or wait for a user event occuring on the selected instant display windows.
               'delay' can be { <0=delay+flush events | 0=event | >0=delay }.
               Command selection (if any) stands for instant display window  indices  instead  of
       image indices.
               If no window indices are specified and if 'delay' is positive, the command results
               in a 'hard' sleep during specified delay.
               Default value: 'delay=0'.

           -warn (+):
                               _force_visible={ 0 | 1 },_message

               Print specified warning message, on the standard error (stderr).
               Command selection (if any) stands for displayed call stack subset instead of image
       indices.

           -window (+):
                               _width[%]>=-1,_height[%]>=-1,_normalization,_fullscreen,_pos_x[%],_pos_y[%],
                                 _title

               Display  selected  images  into  an  instant  display  window with specified size,
       normalization type,
               fullscreen mode and title.
               (eq. to '-w').
               If 'width' or 'height' is set to -1, the corresponding dimension  is  adjusted  to
       the window
               or image size.
               When arguments 'pos_x' and 'pos_y' are both different than -1, the window is moved
       to
               the specified coordinates.
               'width'=0 or 'height'=0 closes the instant display window.
               'normalization' can be { -1=keep same | 0=none | 1=always | 2=1st-time | 3=auto }.
               'fullscreen' can be { -1=keep same | 0=no | 1=yes }.
               You can manage up to 10 different instant display windows by  using  the  numbered
       variants
               '-w0' (default, eq. to '-w'),'-w1',...,'-w9' of the command '-w'.
               Invoke  '-window'  with  no  selection  to make the window visible, if is has been
       closed by the
                 user.
               Default       values:        'width=height=normalization=fullscreen=-1'        and
       'title=(undefined)'.

        ** List manipulation:

           -keep (+):

               Keep only selected images.
               (eq. to '-k').

           -move (+):
                               position[%]

               Move selected images at specified position.
               (eq. to '-mv').

           -name (+):
                               "name"

               Set name of selected images.
               (eq. to '-nm').

           -names:
                               name1,name2,...,nameN

               Set  each  name  of  (multiple)  selected images from the sequence of the provided
       arguments.
               (eq. to '-nms').

           -remove (+):

               Remove selected images.
               (eq. to '-rm').

           -remove_duplicates:

               Remove duplicates images in the selected images list.

           -remove_empty:

               Remove empty images in the selected image list.

           -reverse (+):

               Reverse positions of selected images.
               (eq. to '-rv').

           -sort_list:
                               _ordering={ + | - },_criterion

               Sort list of selected images according to the specified image criterion.
               Default values: 'ordering=+', 'criterion=i'.

           -sort_str:

               Sort selected images (viewed as a list of strings) in lexicographic order.

        ** Mathematical operators:

           -abs (+):

               Compute the pointwise absolute values of selected images.

           -acos (+):

               Compute the pointwise arc-cosine of selected images.

           -add (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Add specified value, image or mathematical expression to selected images,
               or compute the pointwise sum of selected images.
               (eq. to '-+').

           -and (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the bitwise  AND  of  selected  images  with  specified  value,  image  or
       mathematical
               expression, or compute the pointwise sequential bitwise AND of selected images.
               (eq. to '-&').

           -asin (+):

               Compute the pointwise arc-sine of selected images.

           -atan (+):

               Compute the pointwise arc-tangent of selected images.

           -atan2 (+):
                               [x_argument]

               Compute the pointwise oriented arc-tangent of selected images.
               Each  selected  image  is  regarded as the y-argument of the arc-tangent function,
       while the
               specified image gives the corresponding x-argument.

           -bsl (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the bitwise left shift of selected images with specified value, image or
               mathematical expression, or compute the pointwise sequential bitwise left shift of
               selected images.
               (eq. to '-<<').

           -bsr (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the bitwise right shift of selected images with specified value, image or"
               mathematical expression, or compute the pointwise sequential bitwise  right  shift
       of
               selected images.
               (eq. to '->>').

           -cos (+):

               Compute the pointwise cosine of selected images.

           -cosh (+):

               Compute the pointwise hyperbolic cosine of selected images.

           -div (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Divide selected image by specified value, image or mathematical expression,
               or compute the pointwise quotient of selected images.
               (eq. to '-/').

           -div_complex:
                               [divider_real,divider_imag],_epsilon>=0

               Perform  division  of  the selected complex pairs (real1,imag1,...,realN,imagN) of
       images by
                 specified complex pair of images (divider_real,divider_imag).
               In complex pairs, the real image must be always located before the imaginary image
       in the image
                 list.
               Default value: 'epsilon=1e-8'.

           -eq (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the boolean equality of selected images with specified value, image or
               mathematical expression, or compute the boolean equality of selected images.
               (eq. to '-==').

           -exp (+):

               Compute the pointwise exponential of selected images.

           -ge (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute  the  boolean  'greater  or  equal than' of selected images with specified
       value, image
               or mathematical expression, or compute the boolean  'greater  or  equal  than'  of
       selected images.
               (eq. to '->=').

           -gt (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute  the boolean 'greater than' of selected images with specified value, image
       or
               mathematical expression, or compute the boolean 'greater than' of selected images.
               (eq. to '->').

           -le (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the boolean 'less or equal than' of selected images with specified  value,
       image or
               mathematical  expression,  or compute the boolean 'less or equal than' of selected
       images.
               (eq. to '-<=').

           -lt (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the boolean 'less than' of selected images with specified value, image or
               mathematical expression, or compute the boolean 'less than' of selected images.
               (eq. to '-<').

           -log (+):

               Compute the pointwise base-e logarithm of selected images.

           -log10 (+):

               Compute the pointwise base-10 logarithm of selected images.

           -log2 (+):

               Compute the pointwise base-2 logarithm of selected images

           -max (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the maximum between selected images and specified value, image or
               mathematical expression, or compute the pointwise maxima between selected images.

           -mdiv (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the matrix division of selected matrices/vectors by specified value, image
       or
               mathematical expression, or compute the matrix division of selected images.
               (eq. to '-//').

           -min (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the minimum between selected images and specified value, image or
               mathematical expression, or compute the pointwise minima between selected images.

           -mod (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the modulo of selected images with specified value, image or mathematical
               expression, or compute the pointwise sequential modulo of selected images.
               (eq. to '-%').

           -mmul (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute  the matrix right multiplication of selected matrices/vectors by specified
       value, image
                 or
               mathematical expression, or compute the matrix right  multiplication  of  selected
       images.
               (eq. to '-**').

           -mul (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Multiply selected images by specified value, image or mathematical expression,
               or compute the pointwise product of selected images.
               (eq. to '-*').

           -mul_channels:
                               value1,_value2,...,_valueN

               Multiply channels of selected images by specified sequence of values.

           -mul_complex:
                               [multiplier_real,multiplier_imag]

               Perform multiplication of the selected complex pairs (real1,imag1,...,realN,imagN)
       of images by
                 specified complex pair of images (multiplier_real,multiplier_imag).
               In complex pairs, the real image must be always located before the imaginary image
       in the image
                 list.

           -neq (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the boolean inequality of selected images with specified value, image or
               mathematical expression, or compute the boolean inequality of selected images.
               (eq. to '-!=').

           -or (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute  the  bitwise  OR  of  selected  images  with  specified  value,  image or
       mathematical
               expression, or compute the pointwise sequential bitwise OR of selected images.
               (eq. to '-|').

           -pow (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Raise selected image to the power of specified value, image or mathematical
               expression, or compute the pointwise sequential powers of selected images.
               (eq. to '-^').

           -rol (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the bitwise left rotation of selected images with specified  value,  image
       or
               mathematical expression, or compute the pointwise sequential bitwise left rotation
       of
               selected images.

           -ror (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the bitwise right rotation of selected images with specified value,  image
       or
               mathematical  expression,  or  compute  the  pointwise  sequential  bitwise  right
       rotation of
               selected images.

           -sign (+):

               Compute the pointwise sign of selected images.

           -sin (+):

               Compute the pointwise sine of selected images.

           -sinc (+):

               Compute the pointwise sinc function of selected images.

           -sinh (+):

               Compute the pointwise hyperbolic sine of selected images.

           -sqr (+):

               Compute the pointwise square function of selected images.

           -sqrt (+):

               Compute the pointwise square root of selected images.

           -sub (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Subtract specified value, image or mathematical expression to selected images,
               or compute the pointwise difference of selected images.
               (eq. to '--').

           -tan (+):

               Compute the pointwise tangent of selected images.

           -tanh (+):

               Compute the pointwise hyperbolic tangent of selected images.

           -xor (+):
                               value[%] |
                               [image] |
                               'formula' |
                               (no arg)

               Compute the bitwise  XOR  of  selected  images  with  specified  value,  image  or
       mathematical
               expression, or compute the pointwise sequential bitwise XOR of selected images.

        ** Values manipulation:

           -apply_curve:
                               0<=smoothness<=1,x0,y0,x1,y1,x2,y2,...,xN,yN

               Apply curve transformation to image values.
               Default values: 'smoothness=1', 'x0=0', 'y0=100'.

           -apply_gamma:
                               gamma>=0

               Apply gamma correction to selected images.

           -balance_gamma:
                               _ref_color1,...

               Compute gamma-corrected color balance of selected image, with respect to specified
       reference
                 color.
               Default value: 'ref_color1=128'.

           -complex2polar:

               Compute complex to polar transforms of selected images.

           -compress_clut:
                               _max_nbpoints>=1,_max_error>=0,_avg_error>=0

               Compress selected color LUTs as sequences of colored keypoints.
               Default values: 'max_nb_points=2048', 'max_error=17.5' and 'avg_error=1.75'.

           -compress_rle:
                               _is_binary_data={ 0 | 1 },_maximum_sequence_length>=0

               Compress selected images as 2xN data matrices, using RLE algorithm.
               Set 'maximum_sequence_length=0' to disable maximum length constraint.
               Default values: 'is_binary_data=0' and 'maximum_sequence_length=0'.

           -cumulate (+):
                               { x | y | z | c }...{ x | y | z | c } |
                               (no arg)

               Compute the cumulative function of specified  image  data,  optionally  along  the
       specified axes.

           -cut (+):
                               { value0[%] | [image0] },{ value1[%] | [image1] } |
                               [image] |
                               (no arg)

               Cut values of selected images in specified range.
               (eq. to '-c').
               (no arg) runs interactive mode (uses the instant display window [0] if opened).
               In this case, the chosen cut values are returned in the status.

           -decompress_clut:
                               _width>0,_height>0,_depth>0

               Decompress color LUT expressed as a list of colored keypoints.
               Default value: 'width=height=depth=64'.

           -decompress_rle:

               Decompress selected 2xN data matrices, using RLE algorithm.

           -discard (+):
                               _value1,_value2,... |
                               { x | y | z | c}...{ x | y | z | c},_value1,_value2,... |
                               (no arg)

               Discard  specified  values  in  selected  images  or discard neighboring duplicate
       values,
               optionally only for the values along the first of a specified axis.
               If no values are specified, neighboring duplicate values are discarded.
               If all pixels of a selected image are discarded, an empty image is returned.

           -eigen2tensor:

               Recompose selected pairs of eigenvalues/eigenvectors as 2x2 or 3x3 tensor fields.

           -endian (+):
                               _datatype

               Reverse data endianness of selected images, eventually considering the pixel being
       of the
                 specified datatype.
               'datatype'  can be { uchar | char | ushort | short | uint | int | uint64 | int64 |
       float |
                 double }.

           -equalize (+):
                               _nb_levels>0[%],_value_min[%],_value_max[%]

               Equalize histograms of selected images.
               If value range is specified, the equalization is  done  only  for  pixels  in  the
       specified
               value range.
               Default values: 'nb_levels=256', 'value_min=0%' and 'value_max=100%'.

           -fill (+):
                               value1,_value2,... |
                               [image] |
                               'formula'

               Fill  selected  images  with  values  read from the specified value list, existing
       image
               or mathematical expression. Single quotes may be omitted in 'formula'.
               (eq. to '-f').

           -float2int8:

               Convert selected float-valued images to 8bits integer representations.

           -int82float:

               Convert selected 8bits integer representations to float-valued images.

           -index (+):
                               { [palette] | predefined_palette },0<=_dithering<=1,_map_palette={
       0 | 1 }

               Index selected vector-valued images by specified vector-valued palette.
               'predefined_palette' can be { 0=default | 1=HSV | 2=lines | 3=hot | 4=cool | 5=jet
       | 6=flag |
                 7=cube }.
               Default values: 'dithering=0' and 'map_palette=0'.

           -inrange:
                               min[%],max[%]

               Detect pixels whose values are in specified range [min,max], in selected images.
               (eq. to '-ir').

           -map (+):
                               [palette],_boundary |
                               predefined_palette,_boundary

               Map specified vector-valued palette to selected indexed scalar images.
               'predefined_palette' can be { 0=default | 1=HSV | 2=lines | 3=hot | 4=cool | 5=jet
       | 6=flag |
                 7=cube }.
               'boundary' can be { 0=dirichlet | 1=neumann | 2=periodic }.
               Default value: 'boundary=0'.

           -map_clut:
                               [clut]

               Map specified RGB color LUT to selected images.

           -mix_channels:
                               (a00,...,aMN)

               Apply specified matrix to channels of selected images.

           -negate:
                               base_value |
                               (no arg)

               Negate image values.
               Default value: 'base_value=(undefined)'.

           -noise (+):
                               std_variation>=0[%],_noise_type

               Add random noise to selected images.
               'noise_type'  can be { 0=gaussian | 1=uniform | 2=salt&pepper | 3=poisson | 4=rice
       }.
               Default value: 'noise_type=0'.

           -normlp:
                               p>=0

               Compute the pointwise Lp-norm norm of vector-valued pixels in selected images.
               Default value: 'p=2'.

           -norm:

               Compute the pointwise euclidean norm of vector-valued pixels in selected images.

           -normalize (+):
                               { value0[%] | [image0] },{ value1[%] | [image1] } |
                               [image]

               Linearly normalize values of selected images in specified range.
               (eq. to '-n').

           -normalize_sum:

               Normalize selected images with a unitary sum.

           -not:

               Apply boolean not operation on selected images.

           -orientation:

               Compute the pointwise orientation of vector-valued pixels in selected images.

           -oneminus:

               For each selected image, compute one minus image.

           -otsu:
                               _nb_levels>0

               Hard-threshold selected images using Otsu's method.
               The computed thresholds are returned as a list of values in the status.
               Default value: 'nb_levels=256'.

           -polar2complex:

               Compute polar to complex transforms of selected images.

           -quantize:
                               nb_levels>=1,_keep_values={ 0 | 1 },_is_uniform={ 0 | 1 }

               Quantize selected images.
               Default value: 'keep_values=1' and 'is_uniform=0'.

           -rand (+):
                               { value0[%] | [image0] },_{ value1[%] | [image1] } |
                               [image]

               Fill selected images with random values uniformly  distributed  in  the  specified
       range.

           -replace:
                               value_src,value_dest

               Replace pixel values in selected images.

           -replace_inf:
                               _expression

               Replace all infinite values in selected images by specified expression.

           -replace_nan:
                               _expression

               Replace all NaN values in selected images by specified expression.

           -replace_seq:
                               "search_seq","replace_seq"

               Search and replace a sequence of values in selected images.

           -replace_str:
                               "search_str","replace_str"

               Search  and replace a string in selected images (viewed as strings, i.e. sequences
       of ascii
                 codes).

           -round (+):
                               rounding_value>=0,_rounding_type |
                               (no arg)

               Round values of selected images.
               'rounding_type' can be { -1=backward | 0=nearest | 1=forward }.
               Default value: 'rounding_type=0'.

           -roundify:
                               gamma>=0

               Apply roundify transformation on float-valued data, with specified gamma.
               Default value: 'gamma=0'.

           -set (+):
                               value,_x[%],_y[%],_z[%],_c[%]

               Set pixel value in selected images, at specified coordinates.
               (eq. to '-=').
               If specified coordinates are outside the image bounds, no action is performed.
               Default values: 'x=y=z=c=0'.

           -threshold (+):
                               value[%],_is_soft={ 0 | 1 } |
                               (no arg)

               Threshold values of selected images.
               'soft' can be { 0=hard-thresholding | 1=soft-thresholding }.
               (no arg) runs interactive mode (uses the instant display window [0] if opened).
               In this case, the chosen threshold value is returned in the status.
               Default value: 'is_soft=0'.

           -unrepeat:

               Remove repetition of adjacent values in selected images.

           -vector2tensor:

               Convert selected vector fields to corresponding tensor fields.

        ** Colors manipulation:

           -adjust_colors:
                               -100<=_brightness<=100,-100<=_contrast<=100,-100<=_gamma<=100,
                                 -100<=_hue_shift<=100,-100<=_saturation<=100,_value_min,_value_max

               Perform a global adjustment of colors on selected images.
               Range  of correct image values are considered to be in [value_min,value_max] (e.g.
       [0,255]).
               If 'value_min==value_max==0', value range is  estimated  from  min/max  values  of
       selected images.
               Processed images have pixel values constrained in [value_min,value_max].
               Default    values:   'brightness=0',   'contrast=0',   'gamma=0',   'hue_shift=0',
       'saturation=0',
                 'value_min=value_max=0'.

           -apply_channels:
                               "command",channels,_value_action={ 0=none | 1=cut | 2=normalize }

               Apply specified command on the chosen color channel(s) of each selected images.
               (eq. to '-ac').
               Argument 'channels' refers to a colorspace, and can be basically one of  {  all  |
       rgba | rgb |
                 lrgb | ycbcr | lab | lch | hsv | hsi | hsl | cmy | cmyk | yiq }.
               You can also focus the processing on one particular channel of this colorspace, by
       setting
                 'channels' as 'colorspace_channel' (e.g. 'hsv_h' for the hue).
               All channel values are considered to be in the [0,255] range.
               Default value: 'value_action=0'.

           -autoindex:
                               nb_colors>0,0<=_dithering<=1,_method={ 0=median-cut | 1=k-means }

               Index selected vector-valued images by adapted colormaps.
               Default values: 'dithering=0' and 'method=1'.

           -bayer2rgb:
                               _GM_smoothness,_RB_smoothness1,_RB_smoothness2

               Transform selected RGB-Bayer sampled images to color images.
               Default values: 'GM_smoothness=RB_smoothness=1' and 'RB_smoothness2=0.5'.

           -cmy2rgb:

               Convert selected images from CMY to RGB colorbases.

           -cmyk2rgb:

               Convert selected images from CMYK to RGB colorbases.

           -colorblind:
                               type={   0=protanopia   |   1=protanomaly   |   2=deuteranopia   |
       3=deuteranomaly |
                                 4=tritanopia | 5=tritanomaly | 6=achromatopsia | 7=achromatomaly
       }

               Simulate color blindness vision.

           -colormap:
                               nb_levels>=0,_method={ 0=median-cut | 1=k-means  },_sort_vectors={
       0 | 1 }

               Estimate best-fitting colormap with 'nb_colors' entries, to index selected images.
               Set 'nb_levels==0' to extract all existing colors of an image.
               Default value: 'method=1' and 'sort_vectors=1'.

           -compose_channels:

               Compose  all  channels of each selected image, using specified arithmetic operator
       (+,-,or,min,...
                 ).
               Default value: '1=+'.

           -direction2rgb:

               Compute RGB representation of selected 2d direction fields.

           -ditheredbw:

               Create dithered B&W version of selected images.

           -fill_color:
                               col1,...,colN

               Fill selected images with specified color.
               (eq. to '-fc').

           -gradient2rgb:
                               _is_orientation={ 0 | 1 }

               Compute RGB representation of 2d gradient of selected images.
               Default value: 'is_orientation=0'.

           -hsi2rgb (+):

               Convert selected images from HSI to RGB colorbases.

           -hsi82rgb:

               Convert selected images from HSI8 to RGB color bases.

           -hsl2rgb (+):

               Convert selected images from HSL to RGB colorbases.

           -hsl82rgb:

               Convert selected images from HSL8 to RGB color bases.

           -hsv2rgb (+):

               Convert selected images from HSV to RGB colorbases.

           -hsv82rgb:

               Convert selected images from HSV8 to RGB color bases.

           -int2rgb:

               Convert selected images from INT24 scalars to RGB.

           -lab2lch:

               Convert selected images from Lab to Lch color bases.

           -lab2rgb (+):
                               illuminant={ 0=D50 | 1=D65 } |
                               (no arg)

               Convert selected images from Lab to RGB colorbases.

           -lab82rgb:
                               illuminant={ 0=D50 | 1=D65 } |
                               (no arg)

               Convert selected images from Lab8 to RGB color bases.

           -lch2lab:

               Convert selected images from Lch to Lab color bases.

           -lch2rgb:

               Convert selected images from Lch to RGB color bases.

           -lch82rgb:

               Convert selected images from Lch8 to RGB color bases.

           -luminance:

               Compute luminance of selected sRGB images.

           -mix_rgb:
                               a11,a12,a13,a21,a22,a23,a31,a32,a33

               Apply 3x3 specified matrix to RGB colors of selected images.
               Default values: 'a11=1', 'a12=a13=a21=0', 'a22=1', 'a23=a31=a32=0' and 'a33=1'.

           -pseudogray:
                               _max_increment>=0,_JND_threshold>=0,_bits_depth>0

               Generate pseudogray colormap with specified increment and perceptual threshold.
               If 'JND_threshold' is 0, no perceptual constraints are applied.
               Default values: 'max_increment=5', 'JND_threshold=2.3' and 'bits_depth=8'.

           -replace_color:
                               tolerance[%]>=0,smoothness[%]>=0,src1,src2,...,dest1,dest2,...

               Replace pixels from/to specified colors in selected images.

           -retinex:
                               _value_offset>0,_colorspace={ hsi | hsv | lab | lrgb | rgb | ycbcr
       },
                                 0<=_min_cut<=100,0<=_max_cut<=100,_sigma_low>0,_sigma_mid>0,_sigma_high>0

               Apply  multi-scale  retinex  algorithm  on  selected  image   to   improve   color
       consistency.
               (as described in the page http://www.ipol.im/pub/art/2014/107/).
               Default    values:   'offset=1',   'colorspace=hsv',   'min_cut=1',   'max_cut=1',
       'sigma_low=15',
                 'sigma_mid=80' and 'sigma_high=250'.

           -rgb2bayer:
                               _start_pattern=0,_color_grid=0

               Transform selected color images to RGB-Bayer sampled images.
               Default values: 'start_pattern=0' and 'color_grid=0'.

           -rgb2cmy:

               Convert selected images from RGB to CMY colorbases.

           -rgb2cmyk:

               Convert selected images from RGB to CMYK colorbases.

           -rgb2hsi (+):

               Convert selected images from RGB to HSI colorbases.

           -rgb2hsi8:

               Convert selected images from RGB to HSI8 color bases.

           -rgb2hsl (+):

               Convert selected images from RGB to HSL colorbases.

           -rgb2hsl8:

               Convert selected images from RGB to HSL8 color bases.

           -rgb2hsv (+):

               Convert selected images from RGB to HSV colorbases.

           -rgb2hsv8:

               Convert selected images from RGB to HSV8 color bases.

           -rgb2lab (+):
                               illuminant={ 0=D50 | 1=D65 } |
                               (no arg)

               Convert selected images from RGB to Lab colorbases.

           -rgb2lab8:
                               illuminant={ 0=D50 | 1=D65 } |
                               (no arg)

               Convert selected images from RGB to Lab8 color bases.

           -rgb2lch:

               Convert selected images from RGB to Lch color bases.

           -rgb2lch8:

               Convert selected images from RGB to Lch8 color bases.

           -rgb2luv:

               Convert selected images from RGB to LUV color bases.

           -rgb2int:

               Convert selected images from RGB to INT24 scalars.

           -rgb2srgb (+):

               Convert selected images from RGB to sRGB colorbases.

           -rgb2xyz:
                               illuminant={ 0=D50 | 1=D65 } |
                               (no arg)

               Convert selected images from RGB to XYZ colorbases.
               Default value: 'illuminant=0'.

           -rgb2xyz8:
                               illuminant={ 0=D50 | 1=D65 } |
                               (no arg)

               Convert selected images from RGB to XYZ8 color bases.

           -rgb2yiq:

               Convert selected images from RGB to YIQ colorbases.

           -rgb2yiq8:

               Convert selected images from RGB to YIQ8 colorbases.

           -rgb2ycbcr:

               Convert selected images from RGB to YCbCr colorbases.

           -rgb2yuv:

               Convert selected images from RGB to YUV colorbases.

           -rgb2yuv8:

               Convert selected images from RGB to YUV8 color bases.

           -remove_opacity:

               Remove opacity channel of selected images.

           -select_color:
                               tolerance[%]>=0,col1,...,colN

               Select pixels with specified color in selected images.

           -sepia:

               Apply sepia tones effect on selected images.

           -solarize:

               Solarize selected images.

           -split_colors:
                               _tolerance>=0,_max_nb_outputs>0,_min_area>0

               Split selected images as several image containing a single color.
               One selected image can be split as at most 'max_nb_outputs' images.
               Output images are sorted by decreasing area of extracted color regions and have an
       additional
                 alpha-channel.
               Default values: 'tolerance=0', 'max_nb_outputs=256' and 'min_area=8'.

           -split_opacity:

               Split color and opacity parts of selected images.

           -srgb2rgb (+):

               Convert selected images from sRGB to RGB colorbases.

           -to_a:

               Force selected images to have an alpha channel.

           -to_color:

               Force selected images to be in color mode (RGB or RGBA).

           -to_colormode:
                               mode={ 0=adaptive | 1=G | 2=GA | 3=RGB | 4=RGBA }

               Force selected images to be in a given color mode.
               Default value: 'mode=0'.

           -to_gray:

               Force selected images to be in GRAY mode.

           -to_graya:

               Force selected images to be in GRAYA mode.

           -to_pseudogray:
                               _max_step>=0,_is_perceptual_constraint={ 0 | 1 },_bits_depth>0

               Convert selected scalar images ([0-255]-valued) to pseudo-gray color images.
               Default    parameters    :    'max_step=5',    'is_perceptual_constraint=1'    and
       'bits_depth=8'.
               The  original  pseudo-gray  technique  has  been  introduced   by   Rich   Franzen
       [http://r0k.us/graphics/
                 pseudoGrey.html].
               Extension  of this technique to arbitrary increments for more tones, has been done
       by David
                 Tschumperle.

           -to_rgb:

               Force selected images to be in RGB mode.

           -to_rgba:

               Force selected images to be in RGBA mode.

           -transfer_colors:
                               [reference_image],_transfer_brightness={ 0 | 1 }

               Transfer colors of the specified reference image to selected images.
               Default value: 'transfer_brightness=0'.

           -transfer_rgb:
                               [target],_gamma>=0,_regularization>=0,_luminosity_constraints>=0,
                                 _rgb_resolution>=0,_is_constraints={ 0 | 1 }

               Transfer colors from selected source images to selected reference image (given  as
       argument).
               'gamma'  determines  the  importance  of  color occurences in the matching process
       (0=none to
                 1=huge).
               'regularization' determines the number  of  guided  filter  iterations  to  remove
       quantization
                 effects.
               'luminosity_constraints'  tells  if luminosity constraints must be applied on non-
       confident
                 matched colors.
               'is_constraints' tells if additional hard color constraints must be set (opens  an
       interactive
                 window).
               Default values: 'gamma=0.3','regularization=8', 'luminosity_constraints=0.1',
                 'rgb_resolution=64' and 'is_constraints=0'.

           -xyz2rgb:
                               illuminant={ 0=D50 | 1=D65 } |
                               (no arg)

               Convert selected images from XYZ to RGB colorbases.
               Default value: 'illuminant=0'.

           -xyz82rgb:
                               illuminant={ 0=D50 | 1=D65 } |
                               (no arg)

               Convert selected images from XYZ8 to RGB color bases.

           -ycbcr2rgb:

               Convert selected images from YCbCr to RGB colorbases.

           -yiq2rgb:

               Convert selected images from YIQ to RGB colorbases.

           -yiq82rgb:

               Convert selected images from YIQ8 to RGB colorbases.

           -yuv2rgb:

               Convert selected images from YUV to RGB colorbases.

           -yuv82rgb:

               Convert selected images from YUV8 to RGB color bases.

        ** Geometry manipulation:

           -append (+):
                               [image],axis,_centering |
                               axis,_centering

               Append  specified image to selected images, or all selected images together, along
       specified
                 axis.
               (eq. to '-a').
               'axis' can be { x | y | z | c }.
               Usual 'centering' values are { 0=left-justified | 0.5=centered | 1=right-justified
       }.
               Default value: 'centering=0'.

           -append_tiles:
                               _M>=0,_N>=0,0<=_centering_x<=1,0<=_centering_y<=1

               Append MxN selected tiles as new images.
               If 'N' is set to 0, number of rows is estimated automatically.
               If 'M' is set to 0, number of columns is estimated automatically.
               If 'M' and 'N' are both set to '0', auto-mode is used.
               If 'M' or 'N' is set to 0, only a single image is produced.
               'centering_x'  and 'centering_y' tells about the centering of tiles when they have
       different
                 sizes.
               Default values: 'M=0', 'N=0', 'centering_x=centering_y=0.5'.

           -apply_scales:
                               "command",number_of_scales>0,_min_scale[%]>=0,_max_scale[%]>=0,_scale_gamma>0,
                                 _interpolation

               Apply specified command on different scales of selected images.
               'interpolation'  can  be  {  0=none  | 1=nearest | 2=average | 3=linear | 4=grid |
       5=bicubic |
                 6=lanczos }.
               Default value: 'min_scale=25%', 'max_scale=100%' and 'interpolation=3'.

           -autocrop (+):
                               value1,value2,... |
                               (no arg)

               Autocrop selected images by specified vector-valued intensity.
               If no arguments are provided, cropping value is guessed.

           -autocrop_components:
                               _threshold[%],_min_area[%]>=0,_is_high_connectivity={   0   |    1
       },_output_type={
                                 0=crop | 1=segmentation | 2=coordinates }

               Autocrop  and extract connected components in selected images, according to a mask
       given as the
                 last channel of
               each of the selected image (e.g. alpha-channel).
               Default  values:  'threshold=0%',  'min_area=0.1%',  'is_high_connectivity=0'  and
       'output_type=1'.

           -autocrop_seq:
                               value1,value2,... | auto

               Autocrop  selected  images  using  the  crop geometry of the last one by specified
       vector-valued
                 intensity,
               or by automatic guessing the cropping value.
               Default value: auto mode.

           -channels (+):
                               { [image0] | c0[%] },_{ [image1] | c1[%] }

               Keep only specified channels of selected images.
               Dirichlet boundary is used when specified channels are out of range.

           -columns (+):
                               { [image0] | x0[%] },_{ [image1] | x1[%] }

               Keep only specified columns of selected images.
               Dirichlet boundary is used when specified columns are out of range.

           -crop (+):
                               x0[%],x1[%],_boundary |
                               x0[%],y0[%],x1[%],y1[%],_boundary |
                               x0[%],y0[%],z0[%],x1[%],y1[%],z1[%],_boundary |
                               x0[%],y0[%],z0[%],c0[%],x1[%],y1[%],z1[%],c1[%],_boundary |
                               (no arg)

               Crop selected images with specified region coordinates.
               (eq. to '-z').
               'boundary' can be { 0=dirichlet | 1=neumann }.
               (no arg) runs interactive mode (uses the instant display window [0] if opened).
               Default value: 'boundary=0'.

           -diagonal:

               Transform selected vectors as diagonal matrices.

           -elevate:
                               _depth,_is_plain={ 0 | 1 },_is_colored={ 0 | 1 }

               Elevate selected 2d images into 3d volumes.
               Default values: 'depth=64', 'is_plain=1' and 'is_colored=1'.

           -expand_x:
                               size_x>=0,_boundary={ 0=dirichlet | 1=neumann | 2=periodic }

               Expand selected images along the x-axis.
               Default value: 'border=1'.

           -expand_xy:
                               size>=0,_boundary={ 0=dirichlet | 1=neumann | 2=periodic }

               Expand selected images along the xy-axes.
               Default value: 'border=1'.

           -expand_xyz:
                               size>=0,_boundary={ 0=dirichlet | 1=neumann | 2=periodic }

               Expand selected images along the xyz-axes.
               Default value: 'border=1'.

           -expand_y:
                               size_y>=0,_boundary={ 0=dirichlet | 1=neumann | 2=periodic }

               Expand selected images along the y-axis.
               Default value: 'border=1'.

           -expand_z:
                               size_z>=0,_boundary={ 0=dirichlet | 1=neumann | 2=periodic }

               Expand selected images along the z-axis.
               Default value: 'border=1'.

           -montage:
                               "_layout_code",_montage_mode={  0<=centering<=1  |   2<=scale+2<=3
       },_output_mode={
                                 0=single layer | 1=multiple layers },"_processing_command"

               Create  a single image montage from selected images, according to specified layout
       code :
               - 'X' to assemble all images using an automatically estimated layout.
               - 'H' to assemble all images horizontally.
               - 'V' to assemble all images vertically.
               - 'A' to assemble all images as an horizontal array.
               - 'B' to assemble all images as a vertical array.
               - 'Ha:b' to assemble two blocks 'a' and 'b' horizontally.
               - 'Va:b' to assemble two blocks 'a' and 'b' vertically.
               - 'Ra' to rotate a block 'a' by 90 deg. ('RRa' for 180 deg.  and  'RRRa'  for  270
       deg.).
               - 'Ma' to mirror a block 'a' along the X-axis ('MRRa' for the Y-axis).
               A  block  'a'  can  be  an  image indice (treated periodically) or a nested layout
       expression 'Hb:c',
                 'Vb:c','Rb' or 'Mb' itself.
               For example, layout code 'H0:V1:2' creates an image where  image  [0]  is  on  the
       left, and images
                 [1] and [2] vertically packed on the right.
               Default    values:    'layout_code=X',   'montage_mode=2',   output_mode='0'   and
       'processing_command=""'.

           -mirror (+):
                               { x | y | z }...{ x | y | z }

               Mirror selected images along specified axes.

           -permute (+):
                               permutation_string

               Permute selected image axes by specified permutation.
               'permutation' is a combination of the character set {x|y|z|c},
               e.g. 'xycz', 'cxyz', ...

           -resize (+):
                               [image],_interpolation,_boundary,_ax,_ay,_az,_ac |
                               {[image_w] | width>0[%]},_{[image_h] | height>0[%]},_{[image_d]  |
       depth>0[%]},
                                 _{[image_s]                                                    |
       spectrum>0[%]},_interpolation,_boundary,_ax,_ay,_az,_ac |
                               (no arg)

               Resize selected images with specified geometry.
               (eq. to '-r').
               'interpolation' can be { -1=none (memory content) | 0=none | 1=nearest | 2=average
       | 3=linear |
                 4=grid | 5=bicubic | 6=lanczos }.
               'boundary' has different meanings, according to the chosen 'interpolation' mode :
               . When 'interpolation=={ -1 | 1 | 2 | 4 }', 'boundary' is meaningless.
               .  When  'interpolation==0',  'boundary'  can  be  {  0=dirichlet  |  1=neumann  |
       2=periodic }.
               . When 'interpolation=={ 3 | 5 | 6 }', 'boundary' can be { 0=none | 1=neumann }.
               'ax,ay,az,ac' set the centering along each axis when 'interpolation=0 or 4'
               (set to '0' by default, must be defined in range [0,1]).
               (no arg) runs interactive mode (uses the instant display window [0] if opened).
               Default values: 'interpolation=1', 'boundary=0' and 'ax=ay=az=ac=0'.

           -resize_pow2:
                               _interpolation,_boundary,_ax,_ay,_az,_ac

               Resize selected images so that each dimension is a power of 2.
               'interpolation' can be { -1=none (memory content) | 0=none | 1=nearest | 2=average
       | 3=linear |
                 4=grid | 5=bicubic | 6=lanczos }.
               'boundary' has different meanings, according to the chosen 'interpolation' mode :
               . When 'interpolation=={ -1 | 1 | 2 | 4 }', 'boundary' is meaningless.
               .  When  'interpolation==0',  'boundary'  can  be  {  0=dirichlet  |  1=neumann  |
       2=periodic }.
               . When 'interpolation=={ 3 | 5 | 6 }', 'boundary' can be { 0=none | 1=neumann }.
               'ax,ay,az,ac' set the centering along each axis when 'interpolation=0'
               (set to '0' by default, must be defined in range [0,1]).
               Default values: 'interpolation=0', 'boundary=0' and 'ax=ay=az=ac=0'.

           -resize_ratio2d:
                               width>0,height>0,_mode={   0=inside   |   1=outside   |   2=padded
       },0=<_interpolation<=6

               Resize selected images while preserving their aspect ratio.
               (eq. to '-rr2d').
               Default values: 'mode=0' and 'interpolation=6'.

           -resize2dx:
                               width[%]>0,_interpolation,_boundary,_ax,_ay,_az,_ac

               Resize selected images along the x-axis, preserving 2d ratio.
               (eq. to '-r2dx').
               'interpolation' can be { -1=none (memory content) | 0=none | 1=nearest | 2=average
       | 3=linear |
                 4=grid | 5=bicubic | 6=lanczos }.
               'boundary' has different meanings, according to the chosen 'interpolation' mode :
               . When 'interpolation=={ -1 | 1 | 2 | 4 }', 'boundary' is meaningless.
               .  When  'interpolation==0',  'boundary'  can  be  {  0=dirichlet  |  1=neumann  |
       2=periodic }.
               . When 'interpolation=={ 3 | 5 | 6 }', 'boundary' can be { 0=none | 1=neumann }.
               'ax,ay,az,ac' set the centering along each axis when 'interpolation=0'
               (set to '0' by default, must be defined in range [0,1]).
               Default values: 'interpolation=3', 'boundary=0' and 'ax=ay=az=ac=0'.

           -resize2dy:
                               height[%]>=0,_interpolation,_boundary,_ax,_ay,_az,_ac

               Resize selected images along the y-axis, preserving 2d ratio.
               (eq. to '-r2dy').
               'interpolation' can be { -1=none (memory content) | 0=none | 1=nearest | 2=average
       | 3=linear |
                 4=grid | 5=bicubic | 6=lanczos }.
               'boundary' has different meanings, according to the chosen 'interpolation' mode :
               . When 'interpolation=={ -1 | 1 | 2 | 4 }', 'boundary' is meaningless.
               .  When  'interpolation==0',  'boundary'  can  be  {  0=dirichlet  |  1=neumann  |
       2=periodic }.
               . When 'interpolation=={ 3 | 5 | 6 }', 'boundary' can be { 0=none | 1=neumann }.
               'ax,ay,az,ac' set the centering along each axis when 'interpolation=0'
               (set to '0' by default, must be defined in range [0,1]).
               Default values: 'interpolation=3', 'boundary=0' and 'ax=ay=az=ac=0'.

           -resize3dx:
                               width[%]>0,_interpolation,_boundary,_ax,_ay,_az,_ac

               Resize selected images along the x-axis, preserving 3d ratio.
               (eq. to '-r3dx').
               'interpolation' can be { -1=none (memory content) | 0=none | 1=nearest | 2=average
       | 3=linear |
                 4=grid | 5=bicubic | 6=lanczos }.
               'boundary' has different meanings, according to the chosen 'interpolation' mode :
               . When 'interpolation=={ -1 | 1 | 2 | 4 }', 'boundary' is meaningless.
               .  When  'interpolation==0',  'boundary'  can  be  {  0=dirichlet  |  1=neumann  |
       2=periodic }.
               . When 'interpolation=={ 3 | 5 | 6 }', 'boundary' can be { 0=none | 1=neumann }.
               'ax,ay,az,ac' set the centering along each axis when 'interpolation=0'
               (set to '0' by default, must be defined in range [0,1]).
               Default values: 'interpolation=3', 'boundary=0' and 'ax=ay=az=ac=0'.

           -resize3dy:
                               height[%]>0,_interpolation,_boundary,_ax,_ay,_az,_ac

               Resize selected images along the y-axis, preserving 3d ratio.
               (eq. to '-r3dy').
               'interpolation' can be { -1=none (memory content) | 0=none | 1=nearest | 2=average
       | 3=linear |
                 4=grid | 5=bicubic | 6=lanczos }.
               'boundary' has different meanings, according to the chosen 'interpolation' mode :
               . When 'interpolation=={ -1 | 1 | 2 | 4 }', 'boundary' is meaningless.
               .  When  'interpolation==0',  'boundary'  can  be  {  0=dirichlet  |  1=neumann  |
       2=periodic }.
               . When 'interpolation=={ 3 | 5 | 6 }', 'boundary' can be { 0=none | 1=neumann }.
               'ax,ay,az,ac' set the centering along each axis when 'interpolation=0'
               (set to '0' by default, must be defined in range [0,1]).
               Default values: 'interpolation=3', 'boundary=0' and 'ax=ay=az=ac=0'.

           -resize3dz:
                               depth[%]>0,_interpolation,_boundary,_ax,_ay,_az,_ac

               Resize selected images along the z-axis, preserving 3d ratio.
               (eq. to '-r3dz').
               'interpolation' can be { -1=none (memory content) | 0=none | 1=nearest | 2=average
       | 3=linear |
                 4=grid | 5=bicubic | 6=lanczos }.
               'boundary' has different meanings, according to the chosen 'interpolation' mode :
               . When 'interpolation=={ -1 | 1 | 2 | 4 }', 'boundary' is meaningless.
               .  When  'interpolation==0',  'boundary'  can  be  {  0=dirichlet  |  1=neumann  |
       2=periodic }.
               . When 'interpolation=={ 3 | 5 | 6 }', 'boundary' can be { 0=none | 1=neumann }.
               'ax,ay,az,ac' set the centering along each axis when 'interpolation=0'
               (set to '0' by default, must be defined in range [0,1]).
               Default values: 'interpolation=3', 'boundary=0' and 'ax=ay=az=ac=0'.

           -rotate (+):
                               angle,_interpolation,_boundary,_center_x[%],_center_y[%] |
                               u,v,w,angle,interpolation,boundary,_center_x[%],_center_y[%],_center_z[%]

               Rotate selected images with specified angle (in  deg.),  and  optionally  3d  axis
       (u,v,w).
               'interpolation' can be { 0=none | 1=linear | 2=bicubic }.
               'boundary' can be { 0=dirichlet | 1=neumann | 2=periodic }.
               When  a  rotation  center  (cx,cy,_cz)  is  specified,  the  size  of the image is
       preserved.
               Default        values:         'interpolation=1',         'boundary=0'         and
       'center_x=center_y=(undefined)'.

           -rotate_tileable:
                               angle,_max_size_factor>=0

               Rotate selected images by specified angle and make them tileable.
               If resulting size of an image is too big, the image is replaced by a 1x1 image.
               Default values: 'max_size_factor=8'.

           -rows (+):
                               { [image0] | y0[%] },_{ [image1] | y1[%] }

               Keep only specified rows of selected images.
               Dirichlet boundary is used when specified rows are out of range.

           -scale2x:

               Resize selected images using the Scale2x algorithm.

           -scale3x:

               Resize selected images using the Scale3x algorithm.

           -scale_dcci2x:
                               _edge_threshold>=0,_exponent>0,_extend_1px={ 0=false | 1=true }

               Double image size using directional cubic convolution interpolation,
               as                                   described                                  in
       https://en.wikipedia.org/wiki/Directional_Cubic_Convolution_Interpolation.
               Default values: 'edge_threshold=1.15', 'exponent=5' and 'extend_1px=0'.

           -seamcarve:
                               _width[%]>=0,_height[%]>=0,_is_priority_channel={    0     |     1
       },_is_antialiasing={ 0 |
                                  1 },_maximum_seams[%]>=0

               Resize  selected  images  with  specified  2d  geometry,  using  the  seam-carving
       algorithm.
               Default values: 'height=100%', 'is_priority_channel=0', 'is_antialiasing=1' and
                 'maximum_seams=25%'.

           -shift (+):
                               vx[%],_vy[%],_vz[%],_vc[%],_boundary

               Shift selected images by specified displacement vector.
               Displacement vector can be non-integer in which case linear interpolation  of  the
       shift is
                 computed.
               'boundary' can be { 0=dirichlet | 1=neumann | 2=periodic }.
               Default value: 'boundary=0'.

           -shrink_x:
                               size_x>=0

               Shrink selected images along the x-axis.

           -shrink_xy:
                               size>=0

               Shrink selected images along the xy-axes.

           -shrink_xyz:
                               size>=0

               Shrink selected images along the xyz-axes.

           -shrink_y:
                               size_y>=0

               Shrink selected images along the y-axis.

           -shrink_z:
                               size_z>=0

               Shrink selected images along the z-axis.

           -slices (+):
                               { [image0] | z0[%] },_{ [image1] | z1[%] }

               Keep only specified slices of selected images.
               Dirichlet boundary is used when specified slices are out of range.

           -sort (+):
                               _ordering={ + | - },_axis={ x | y | z | c }

               Sort pixel values of selected images.
               If  'axis'  is  specified,  the sorting is done according to the data of the first
       column/row/slice/
                 channel
               of selected images.
               Default values: 'ordering=+' and 'axis=(undefined)'.

           -split (+):
                               { x | y | z | c }...{ x | y | z | c },_split_mode |
                               keep_splitting_values={ + | - },_{ x | y | z | c }...{ x | y | z |
       c },value1,
                                 _value2,... |
                               (no arg)

               Split  selected  images along specified axes, or regarding to a sequence of scalar
       values
                 (optionally along specified axes too).
               (eq. to '-s').
               'split_mode' can be { 0=split according to constant values | >0=split in N parts |
       <0=split in
                 parts of size -N }.
               Default value: 'split_mode=-1'.

           -split_tiles:
                               M!=0,_N!=0,_is_homogeneous={ 0 | 1 }

               Split selected images as a MxN array of tiles.
               If M or N is negative, it stands for the tile size instead.
               Default values: 'N=M' and 'is_homogeneous=0'.

           -unroll (+):
                               _axis={ x | y | z | c }

               Unroll selected images along specified axis.
               (eq. to '-y').
               Default value: 'axis=y'.

           -upscale_smart:
                               width[%],_height[%],_depth,_smoothness>=0,_anisotropy=[0,1],sharpening>=0

               Upscale selected images with an edge-preserving algorithm.
               Default values: 'height=100%', 'depth=100%', 'smoothness=2', 'anisotropy=0.4' and
                 'sharpening=10'.

           -warp (+):
                               [warping_field],_mode,_interpolation,_boundary,_nb_frames>0

               Warp selected image with specified displacement field.
               'mode' can be { 0=backward-absolute | 1=backward-relative | 2=forward-absolute |
                 3=forward-relative }.
               'interpolation' can be { 0=nearest-neighbor | 1=linear | 2=cubic }.
               'boundary' can be { 0=dirichlet | 1=neumann | 2=periodic }.
               Default values: 'mode=0', 'interpolation=1', 'boundary=1' and 'nb_frames=1'.

        ** Filtering:

           -bandpass:
                               _min_freq[%],_max_freq[%]

               Apply bandpass filter to selected images.
               Default values: 'min_freq=0' and 'max_freq=20%'.

           -bilateral (+):
                               [guide],std_variation_s[%]>=0,std_variation_r[%]>=0,_sampling_s>=0,
                                 _sampling_r>=0 |
                               std_variation_s[%]>=0,std_variation_r[%]>=0,_sampling_s>=0,_sampling_r>=0

               Blur selected images by anisotropic (eventually joint/cross) bilateral filtering.
               If a guide image is provided, it is used for drive the smoothing filter.
               A guide image must be of the same xyz-size as the selected images.
               Set 'sampling' arguments to '0' for automatic adjustment.

           -blur (+):
                               std_variation>=0[%],_boundary,_kernel |
                               axes,std_variation>=0[%],_boundary,_kernel

               Blur  selected  images  by  a  quasi-gaussian  or   gaussian   filter   (recursive
       implementation).
               (eq. to '-b').
               'boundary'  can  be  {  0=dirichlet  |  1=neumann } and 'kernel' can be { 0=quasi-
       gaussian (faster) |
                 1=gaussian }.
               When specified, argument 'axes' is a sequence of { x | y | z | c }.
               Specifying one axis multiple times apply also the blur multiple times.
               Default values: 'boundary=1' and 'kernel=0'.

           -blur_angular:
                               amplitude[%],_center_x[%],_center_y[%]

               Apply angular blur on selected images.
               Default values: 'center_x=center_y=50%'.

           -blur_linear:
                               amplitude1[%],_amplitude2[%],_angle,_boundary={   0=dirichlet    |
       1=neumann }

               Apply linear blur on selected images, with specified angle and amplitudes.
               Default values: 'amplitude2=0', 'angle=0' and 'boundary=1'.

           -blur_radial:
                               amplitude[%],_center_x[%],_center_y[%]

               Apply radial blur on selected images.
               Default values: 'center_x=center_y=50%'.

           -blur_selective:
                               sigma>=0,_edges>0,_nb_scales>0

               Blur selected images using selective gaussian scales.
               Default values: 'sigma=5', 'edges=0.5' and 'nb_scales=5'.

           -blur_x:
                               amplitude[%]>=0,_boundary={ 0=dirichlet | 1=neumann }

               Blur selected images along the x-axis.
               Default value: 'boundary=1'.

           -blur_xy:
                               amplitude_x[%],amplitude_y[%],_boundary={  0=dirichlet | 1=neumann
       }

               Blur selected images along the X and Y axes.
               Default value: 'boundary=1'.

           -blur_xyz:
                               amplitude_x[%],amplitude_y[%],amplitude_z,_boundary={  0=dirichlet
       | 1=neumann }

               Blur selected images along the X, Y and Z axes.
               Default value: 'boundary=1'.

           -blur_y:
                               amplitude[%]>=0,_boundary={ 0=dirichlet | 1=neumann }

               Blur selected images along the y-axis.
               Default value: 'boundary=1'.

           -blur_z:
                               amplitude[%]>=0,_boundary={ 0=dirichlet | 1=neumann }

               Blur selected images along the z-axis.
               Default value: 'boundary=1'.

           -boxfilter (+):
                               size>=0[%],_order,_boundary |
                               axes,size>=0[%],_order,_boundary

               Blur selected images by a box filter of specified size (recursive implementation).
               'order' can be { 0=smooth | 1=1st-derivative | 2=2nd-derivative }.
               'boundary'  can  be  {  0=dirichlet  |  1=neumann } and 'kernel' can be { 0=quasi-
       gaussian (faster) |
                 1=gaussian }.
               When specified, argument 'axes' is a sequence of { x | y | z | c }.
               Specifying one axis multiple times apply also the blur multiple times.
               Default values: 'order=0' and 'boundary=1'.

           -compose_freq:

               Compose selected low and high frequency parts into new images.

           -convolve (+):
                               [mask],_boundary,_is_normalized={ 0 | 1 }

               Convolve selected images by specified mask.
               'boundary' can be { 0=dirichlet | 1=neumann }.
               Default values: 'boundary=1' and 'is_normalized=0'.

           -convolve_fft:
                               [mask]

               Convolve selected images with specified mask, in the fourier domain.

           -correlate (+):
                               [mask],_boundary,_is_normalized={ 0 | 1 }

               Correlate selected images by specified mask.
               'boundary' can be { 0=dirichlet | 1=neumann }.
               Default values: 'boundary=1' and 'is_normalized=0'.

           -cross_correlation:
                               [mask]

               Compute cross-correlation of selected images with specified mask.

           -curvature:

               Compute isophote curvatures on selected images.

           -dct:
                               _{ x | y | z }...{ x | y | z } |
                               (no arg)

               Compute the discrete cosine transform of selected images,
               optionally along the specified axes only.
               Default values: (no arg)

           -deblur:
                               amplitude[%]>=0,_nb_iter>=0,_dt>=0,_regul>=0,_regul_type={
       0=Tikhonov |
                                 1=meancurv. | 2=TV }

               Deblur image using a regularized Jansson-Van Cittert algorithm.
               Default values: 'nb_iter=10', 'dt=20', 'regul=0.7' and 'regul_type=1'.

           -deblur_goldmeinel:
                               sigma>=0,  _nb_iter>=0,  _acceleration>=0, _kernel_type={ 0=quasi-
       gaussian
                                 (faster) | 1=gaussian }.

               Deblur selected images using Gold-Meinel algorithm
               Default values: 'nb_iter=8', 'acceleration=1' and 'kernel_type=1'.

           -deblur_richardsonlucy:
                               sigma>=0, nb_iter>=0, _kernel_type={ 0=quasi-gaussian  (faster)  |
       1=gaussian }.

               Deblur selected images using Richardson-Lucy algorithm.
               Default values: 'nb_iter=50' and 'kernel_type=1'.

           -deconvolve_fft:
                               [kernel],_regularization>=0

               Deconvolve selected images by specified mask in the fourier space.
               Default value: 'regularization>=0'.

           -deinterlace:
                               _method={ 0 | 1 }

               Deinterlace  selected images ('method' can be { 0=standard or 1=motion-compensated
       }).
               Default value: 'method=0'.

           -denoise (+):
                               std_variation_s>=0,_std_variation_p>=0,_patch_size>0,_lookup_size>0,_smoothness,
                                 _fast_approx={ 0 | 1 }

               Denoise selected images by non-local patch averaging.
               Default   values:   'std_variation_p=10',   'patch_size=5',   'lookup_size=6'  and
       'smoothness=1'.

           -denoise_haar:
                               _threshold>=0,_nb_scales>=0,_cycle_spinning>0

               Denoise selected image using haar-wavelet thresholding with cycle spinning.
               Set 'nb_scales==0' to automatically determine the optimal number of scales.
               Default values: 'threshold=1.4', 'nb_scale=0' and 'cycle_spinning=10'.

           -denoise_patchpca:
                               _strength>=0,_patch_size>0,_lookup_size>0,_spatial_sampling>0

               Denoise selected images using the patch-pca algorithm.
               Default    values:    'patch_size=7',    'lookup_size=11',    'details=1.8'    and
       'spatial_sampling=5'.

           -deriche (+):
                               std_variation>=0[%],order={  0  |  1  |  2  },axis={ x | y | z | c
       },_boundary

               Apply Deriche recursive filter on selected images, along specified axis and with
               specified standard deviation, order and boundary conditions.
               'boundary' can be { 0=dirichlet | 1=neumann }.
               Default value: 'boundary=1'.

           -dilate (+):
                               size>=0 |
                               size_x>=0,size_y>=0,size_z>=0 |
                               [kernel],_boundary,_is_real={ 0=binary-mode | 1=real-mode }

               Dilate selected images by a rectangular or the specified structuring element.
               'boundary' can be { 0=dirichlet | 1=neumann }.
               Default values: 'size_z=1', 'boundary=1' and 'is_real=0'.

           -dilate_circ:
                               _size>=0,_boundary,_is_normalized={ 0 | 1 }

               Apply circular dilation of selected image by specified size.
               Default values: 'boundary=1' and 'is_normalized=0'.

           -dilate_oct:
                               _size>=0,_boundary,_is_normalized={ 0 | 1 }

               Apply octagonal dilation of selected image by specified size.
               Default values: 'boundary=1' and 'is_normalized=0'.

           -dilate_threshold:
                               size_x>=1,size_y>=1,size_z>=1,_threshold>=0,_boundary

               Dilate selected images in the (X,Y,Z,I) space.
               'boundary' can be { 0=dirichlet | 1=neumann }.
               Default values: 'size_y=size_x', 'size_z=1', 'threshold=255' and 'boundary=1'.

           -divergence:

               Compute divergence of selected vector fields.

           -dog:
                               _sigma1>=0[%],_sigma2>=0[%]

               Compute difference of gaussian on selected images.
               Default values: 'sigma1=2%' and 'sigma2=3%'.

           -diffusiontensors:
                               _sharpness>=0,0<=_anisotropy<=1,_alpha[%],_sigma[%],is_sqrt={ 0  |
       1 }

               Compute  the  diffusion  tensors  of selected images for edge-preserving smoothing
       algorithms.
               Default values: 'sharpness=0.7', 'anisotropy=0.3',  'alpha=0.6',  'sigma=1.1'  and
       'is_sqrt=0'.

           -edges:
                               _threshold[%]>=0

               Estimate contours of selected images.
               Default value: 'edges=15%'

           -erode (+):
                               size>=0 |
                               size_x>=0,size_y>=0,_size_z>=0 |
                               [kernel],_boundary,_is_real={ 0=binary-mode | 1=real-mode }

               Erode selected images by a rectangular or the specified structuring element.
               'boundary' can be { 0=dirichlet | 1=neumann }.
               Default values: 'size_z=1', 'boundary=1' and 'is_real=0'.

           -erode_circ:
                               _size>=0,_boundary,_is_normalized={ 0 | 1 }

               Apply circular erosion of selected images by specified size.
               Default values: 'boundary=1' and 'is_normalized=0'.

           -erode_oct:
                               _size>=0,_boundary,_is_normalized={ 0 | 1 }

               Apply octagonal erosion of selected images by specified size.
               Default values: 'boundary=1' and 'is_normalized=0'.

           -erode_threshold:
                               size_x>=1,size_y>=1,size_z>=1,_threshold>=0,_boundary

               Erode selected images in the (X,Y,Z,I) space.
               'boundary' can be { 0=dirichlet | 1=neumann }.
               Default values: 'size_y=size_x', 'size_z=1', 'threshold=255' and 'boundary=1'.

           -fft (+):
                               _{ x | y | z }...{ x | y | z }

               Compute  the  direct  fourier  transform  (real  and  imaginary parts) of selected
       images,
               optionally along the specified axes only.

           -gradient (+):
                               { x | y | z }...{ x | y | z },_scheme |
                               (no arg)

               Compute the gradient components (first derivatives) of selected images.
               (eq. to '-g').
               'scheme' can be { -1=backward | 0=centered | 1=forward  |  2=sobel  |  3=rotation-
       invariant
                 (default) | 4=deriche | 5=vanvliet }.
               (no arg) compute all significant 2d/3d components.
               Default value: 'scheme=3'.

           -gradient_norm:

               Compute gradient norm of selected images.

           -gradient_orientation:
                               _dimension={1,2,3}

               Compute N-d gradient orientation of selected images.
               Default value: 'dimension=3'.

           -guided (+):
                               [guide],radius[%]>=0,regularization[%]>=0 |
                               radius[%]>=0,regularization[%]>=0

               Blur selected images by guided image filtering.
               If a guide image is provided, it is used to drive the smoothing process.
               A guide image must be of the same xyz-size as the selected images.
               This command implements the filtering algorithm described in:
               He,  Kaiming;  Sun, Jian; Tang, Xiaoou, "Guided Image Filtering," Pattern Analysis
       and Machine
                 Intelligence,
               IEEE Transactions on , vol.35, no.6, pp.1397,1409, June 2013

           -haar:
                               scale>0

               Compute the direct haar multiscale wavelet transform of selected images.

           -heat_flow:
                               _nb_iter>=0,_dt,_keep_sequence={ 0 | 1 }

               Apply iterations of the heat flow on selected images.
               Default values: 'nb_iter=10', 'dt=30' and 'keep_sequence=0'.

           -hessian (+):
                               { xx | xy | xz | yy | yz | zz }...{ xx | xy | xz | yy | yz | zz  }
       |
                               (no arg)

               Compute the hessian components (second derivatives) of selected images.
               (no arg) compute all significant components.

           -idct:
                               _{ x | y | z }...{ x | y | z } |
                               (no arg)

               Compute the inverse discrete cosine transform of selected images,
               optionally along the specified axes only.
               Default values: (no arg)

           -iee:

               Compute gradient-orthogonal-directed 2nd derivative of image(s).

           -ifft (+):
                               _{ x | y | z }...{ x | y | z }

               Compute  the  inverse  fourier  transform  (real  and imaginary parts) of selected
       images.
               optionally along the specified axes only.

           -ihaar:
                               scale>0

               Compute the inverse haar multiscale wavelet transform of selected images.

           -inn:

               Compute gradient-directed 2nd derivative of image(s).

           -inpaint (+):
                               [mask] |
                               [mask],0,_fast_method |
                               [mask],_patch_size>=1,_lookup_size>=1,_lookup_factor>=0,_lookup_increment!=0,
                                 _blend_size>=0,0<=_blend_threshold<=1,_blend_decay>=0,_blend_scales>=1,
                                 _is_blend_outer={ 0 | 1 }

               Inpaint selected images by specified mask.
               If no patch size (or 0) is specified, inpainting is done using a fast  average  or
       median
                 algorithm.
               Otherwise,  it  used  a  patch-based  reconstruction method, that can be very time
       consuming.
               'fast_method' can be { 0=low-connectivity average | 1=high-connectivity average |
                 2=low-connectivity median | 3=high-connectivity median }.
               Default     values:     'patch_size=0',     'fast_method=1',     'lookup_size=22',
       'lookup_factor=0.5',
                 'lookup_increment=1', 'blend_size=0', 'blend_threshold=0', 'blend_decay=0.05',
                 'blend_scales=10' and 'is_blend_outer=1'.

           -inpaint_flow:
                               [mask],_nb_global_iter>=0,_nb_local_iter>=0,_dt>0,_alpha>=0,_sigma>=0

               Apply iteration of the inpainting flow on selected images.
               Default values: 'nb_global_iter=4', 'nb_global_iter=15',  'dt=10',  'alpha=1'  and
       'sigma=3'.

           -inpaint_holes:
                               maximal_area[%]>=0,_tolerance>=0,_is_high_connectivity={ 0 | 1 }

               Inpaint all connected regions having an area less than specified value.
               Default values: 'maximal_area=4', 'tolerance=0' and 'is_high_connectivity=0'.

           -inpaint_morpho:
                               [mask]

               Inpaint selected images by specified mask using morphological operators.

           -inpaint_patchmatch:
                               [mask],_nb_scales={             0=auto             |            >0
       },_patch_size>0,_nb_iterations_per_scale>0,
                                 _blend_size>=0,_allow_outer_blending={       0        |        1
       },_is_already_initialized={ 0 | 1 }

               Inpaint  selected  images by specified binary mask, using a multi-scale patchmatch
       algorithm.
               Default  values:  'nb_scales=0',   'patch_size=9',   'nb_iterations_per_scale=10',
       'blend_size=5',
                 'allow_outer_blending=1' and 'is_already_initialized=0'.

           -inpaint_diffusion:
                               [mask],_nb_scales[%]>=0,_diffusion_type={       0=isotropic      |
       1=delaunay-oriented |
                                 2=edge-oriented },_diffusion_iter>=0

               Inpaint selected images by specified mask using a  multiscale  transport-diffusion
       algorithm.
               Default values: 'nb_scales=75%', 'diffusion_type=1' and 'diffusion_iter=20'.

           -kuwahara:
                               size>0

               Apply Kuwahara filter of specified size on selected images.

           -laplacian:

               Compute Laplacian of selected images.

           -lic:
                               _amplitude>0,_channels>0

               Render LIC representation of selected vector fields.
               Default values: 'amplitude=30' and 'channels=1'.

           -map_tones:
                               _threshold>=0,_gamma>=0,_smoothness>=0,nb_iter>=0

               Apply tone mapping operator on selected images, based on Poisson equation.
               Default values: 'threshold=0.1', 'gamma=0.8', 'smoothness=0.5' and 'nb_iter=30'.

           -map_tones_fast:
                               _radius[%]>=0,_power>=0

               Apply fast tone mapping operator on selected images.
               Default values: 'radius=3%' and 'power=0.3'.

           -meancurvature_flow:
                               _nb_iter>=0,_dt,_keep_sequence={ 0 | 1 }

               Apply iterations of the mean curvature flow on selected images.
               Default values: 'nb_iter=10', 'dt=30' and 'keep_sequence=0'.

           -median (+):
                               size>=0,_threshold>0

               Apply (opt. thresholded) median filter on selected images with structuring element
       size x size.

           -nlmeans:
                               [guide],_patch_radius>0,_spatial_bandwidth>0,_tonal_bandwidth>0,
                                 _patch_measure_command |
                               _patch_radius>0,_spatial_bandwidth>0,_tonal_bandwidth>0,_patch_measure_command

               Apply non local means denoising of Buades et al, 2005. on selected images.
               The patch is a gaussian function of 'std _patch_radius'.
               The spatial kernel is a rectangle of radius 'spatial_bandwidth'.
               The tonal kernel is exponential (exp(-d^2/_tonal_bandwidth^2))
               with d the euclidiean distance between image patches.
               Default values: 'patch_radius=4', 'spatial_bandwidth=4', 'tonal_bandwidth=10' and
                 'patch_measure_command=-norm'.

           -nlmeans_core:
                               _reference_image,_scaling_map,_patch_radius>0,_spatial_bandwidth>0

               Apply non local means denoising using a image for weigth and a map for scaling

           -normalize_local:
                               _amplitude>=0,_radius>0,_n_smooth>=0[%],_a_smooth>=0[%],_is_cut={
       0 | 1 },
                                 _min=0,_max=255

               Normalize selected images locally.
               Default  values:   'amplitude=3',   'radius=16',   'n_smooth=4%',   'a_smooth=2%',
       'is_cut=1', 'min=0'
                 and 'max=255'.

           -normalized_cross_correlation:
                               [mask]

               Compute normalized cross-correlation of selected images with specified mask.

           -peronamalik_flow:
                               K_factor>0,_nb_iter>=0,_dt,_keep_sequence={ 0 | 1 }

               Apply iterations of the Perona-Malik flow on selected images.
               Default values: 'K_factor=20', 'nb_iter=5', 'dt=5' and 'keep_sequence=0'.

           -phase_correlation:
                               [destination]

               Estimate   translation   vector  between  selected  source  images  and  specified
       destination.

           -pde_flow:
                               _nb_iter>=0,_dt,_velocity_command,_keep_sequence={ 0 | 1 }

               Apply iterations of a generic PDE flow on selected images.
               Default   values:   'nb_iter=10',   'dt=30',   'velocity_command=laplacian'    and
       'keep_sequence=0'.

           -periodize_poisson:

               Periodize selected images using a Poisson solver in Fourier space.

           -red_eye:
                               0<=_threshold<=100,_smoothness>=0,0<=attenuation<=1

               Attenuate red-eye effect in selected images.
               Default values: 'threshold=75', 'smoothness=3.5' and 'attenuation=0.1'.

           -remove_hotpixels:
                               _mask_size>0, _threshold[%]>0

               Remove hot pixels in selected images.
               Default values: 'mask_size=3' and 'threshold=10%'.

           -remove_pixels:
                               number_of_pixels[%]>=0

               Remove  specified  number  of pixels (i.e. set them to 0) from the set of non-zero
       pixels in
                 selected images.

           -rolling_guidance:
                               std_variation_s[%]>=0,std_variation_r[%]>=0,_precision>=0

               Apply the rolling guidance filter on selected image.
               Rolling guidance filter is a fast image abstraction filter, described in:
               "Rolling Guidance Filter", Qi Zhang Xiaoyong, Shen Li, Xu Jiaya Jia, ECCV'2014.
               Default values: 'std_variation_s=4', 'std_variation_r=10' and 'precision=0.5'.

           -sharpen (+):
                               amplitude>=0 |
                               amplitude>=0,edge>=0,_alpha,_sigma

               Sharpen selected images by inverse diffusion or shock filters methods.
               'edge' must be specified to enable shock-filter method.
               Default values: 'alpha=0' and 'sigma=0'.

           -smooth (+):
                               amplitude>=0,_sharpness>=0,_anisotropy,_alpha,_sigma,_dl>0,_da>0,_precision>0,
                                 interpolation,_fast_approx={ 0 | 1 } |
                               nb_iterations>=0,_sharpness>=0,_anisotropy,_alpha,_sigma,_dt>0,0 |
                               [tensor_field],_amplitude>=0,_dl>0,_da>0,_precision>0,_interpolation,
                                 _fast_approx={ 0 | 1 } |
                               [tensor_field],_nb_iters>=0,_dt>0,0

               Smooth selected images anisotropically using diffusion PDE's, with specified field
       of
               diffusion tensors.
               'anisotropy' must be in [0,1].
               'interpolation' can be { 0=nearest | 1=linear | 2=runge-kutta }.
               Default   values:  'sharpness=0.7',  'anisotropy=0.3',  'alpha=0.6',  'sigma=1.1',
       'dl=0.8', 'da=30',
                 'precision=2', 'interpolation=0' and 'fast_approx=1'.

           -split_freq:
                               smoothness>0[%]

               Split selected images into low and high frequency parts.

           -solve_poisson:
                               "laplacian_command",_nb_iterations>=0,_time_step>0,_nb_scales>=0

               Solve Poisson equation so that applying '-laplacian[n]' is close to the result of
                 '-laplacian_command[n]'.
               Solving is performed using a multi-scale gradient descent algorithm.
               If 'nb_scales=0', the number of scales is automatically determined.
               Default values: 'nb_iterations=60', 'dt=5' and 'nb_scales=0'.

           -split_details:
                               _nb_scales>0,_base_scale[%]>=0,_detail_scale[%]>=0

               Split selected images into 'nb_scales' detail scales.
               If 'base_scale'=='detail_scale'==0, the image decomposition is done with 'a trous'
       wavelets.
               Otherwise, it uses laplacian pyramids with linear standard deviations.
               Default values: 'nb_scales=4', 'base_scale=0' and 'detail_scale=0'.

           -structuretensors (+):
                               _scheme={ 0=centered | 1=forward/backward }

               Compute the structure tensor field of selected images.
               Default value: 'scheme=1'.

           -solidify:
                               _smoothness[%]>=0,_diffusion_type={   0=isotropic   |  1=delaunay-
       oriented |
                                 2=edge-oriented },_diffusion_iter>=0

               Solidify selected transparent images.
               Default values: 'smoothness=75%', 'diffusion_type=1' and 'diffusion_iter=20'.

           -syntexturize:
                               _width[%]>0,_height[%]>0

               Resynthetize  'width'x'height'  versions  of  selected  micro-textures  by   phase
       randomization.
               The  texture synthesis algorithm is a straightforward implementation of the method
       described in :
               http://www.ipol.im/pub/art/2011/ggm_rpn/
               Default values: 'width=height=100%'.

           -syntexturize_patchmatch:
                               _width[%]>0,_height[%]>0,_nb_scales>=0,_patch_size>0,_blending_size>=0,
                                 _precision>=0

               Resynthetize  'width'x'height'  versions of selected micro-textures using a patch-
       matching
                 algorithm.
               If 'nbscales==0', the number of scales used is estimated from the image size.
               Default    values:     'width=height=100%',     'nb_scales=0',     'patch_size=7',
       'blending_size=5' and
                 'precision=1'.

           -tv_flow:
                               _nb_iter>=0,_dt,_keep_sequence={ 0 | 1 }

               Apply iterations of the total variation flow on selected images.
               Default values: 'nb_iter=10', 'dt=30' and 'keep_sequence=0'.

           -unsharp:
                               radius[%]>=0,_amount>=0,_threshold[%]>=0

               Apply unsharp mask on selected images.
               Default values: 'amount=2' and 'threshold=0'.

           -unsharp_octave:
                               _nb_scales>0,_radius[%]>=0,_amount>=0,threshold[%]>=0

               Apply octave sharpening on selected images.
               Default values: 'nb_scales=4', 'radius=1', 'amount=2' and 'threshold=0'.

           -vanvliet (+):
                               std_variation>=0[%],order={  0  | 1 | 2 | 3 },axis={ x | y | z | c
       },_boundary

               Apply Vanvliet recursive filter on selected images, along specified axis and with
               specified standard deviation, order and boundary conditions.
               'boundary' can be { 0=dirichlet | 1=neumann }.
               Default value: 'boundary=1'.

           -watermark_fourier:
                               text,_size>0

               Add a textual watermark in the frequency domain of selected images.
               Default value: 'size=33'.

           -watershed (+):
                               [priority_image],_is_high_connectivity={ 0 | 1 }

               Compute the watershed transform of selected images.
               Default value: 'is_high_connectivity=1'.

        ** Features extraction:

           -area:
                               tolerance>=0,is_high_connectivity={ 0 | 1 }

               Compute area of connected components in selected images.
               Default values: 'is_high_connectivity=0'.

           -area_fg:
                               tolerance>=0,is_high_connectivity={ 0 | 1 }

               Compute area of connected components for non-zero values in selected images.
               Similar to '-area' except that 0-valued pixels are not considered.
               Default values: 'is_high_connectivity=0'.

           -at_line:
                               x0[%],y0[%],z0[%],x1[%],y1[%],z1[%]

               Retrieve  pixels  of  the  selected  images  belonging  to  the   specified   line
       (x0,y0,z0)-(x1,y1,z1).

           -barycenter:

               Compute the barycenter vector of pixel values.

           -detect_skin:
                               0<=tolerance<=1,_skin_x,_skin_y,_skin_radius>=0

               Detect skin in selected color images and output an appartenance probability map.
               Detection is performed using CbCr chromaticity data of skin pixels.
               If  arguments  'skin_x',  'skin_y' and 'skin_radius' are provided, skin pixels are
       learnt
               from the sample pixels inside  the  circle  located  at  ('skin_x','skin_y')  with
       radius
                 'skin_radius'.
               Default value: 'tolerance=0.5' and 'skin_x=skiny=radius=-1'.

           -displacement (+):
                               [source_image],_smoothness,_precision>=0,_nb_scales>=0,_iteration_max>=0,
                                 is_backward={ 0 | 1 },_[guide]

               Estimate displacement field between specified source and selected target images.
               If 'smoothness>=0', regularization type is set to isotropic, else to anisotropic.
               If 'nbscales==0', the number of scales used is estimated from the image size.
               Default     values:      'smoothness=0.1',      'precision=5',      'nb_scales=0',
       'iteration_max=10000',
                 'is_backward=1' and '[guide]=(unused)'.

           -distance (+):
                               isovalue[%],_metric |
                               isovalue[%],[metric],_method

               Compute  the unsigned distance function to specified isovalue, opt. according to a
       custom metric.
               'metric' can be { 0=chebyshev | 1=manhattan | 2=euclidean | 3=squared-euclidean }.
               'method'  can  be  {  0=fast-marching  |  1=low-connectivity  dijkstra  |  2=high-
       connectivity dijkstra |
                  3=1+return path | 4=2+return path }.
               Default value: 'metric=2' and 'method=0'.

           -float2fft8:

               Convert selected float-valued images to 8bits fourier representations.

           -fft82float:

               Convert selected 8bits fourier representations to float-valued images.

           -fftpolar:

               Compute fourier transform of selected images, as centered magnitude/phase images.

           -histogram (+):
                               _nb_levels>0[%],_value0[%],_value1[%]

               Compute the histogram of selected images.
               If value range is set, the histogram is estimated only for pixels in the specified
               value range. Argument 'value1' must be specified if 'value0' is set.
               Default values: 'nb_levels=256', 'value0=0%' and 'value1=100%'.

           -histogram_nd:
                               nb_levels>0[%],_value0[%],_value1[%]

               Compute the 1d,2d or 3d histogram of selected multi-channels images (having 1,2 or
       3 channels).
               If value range is set, the histogram is estimated only for pixels in the specified
               value range.
               Default values: 'value0=0%' and 'value1=100%'.

           -histogram_cumul:
                               _nb_levels>0,_is_normalized={ 0 | 1 },_val0[%],_val1[%]

               Compute cumulative histogram of selected images.
               Default values: 'nb_levels=256', 'is_normalized=0' and 'val0=val1=0'.

           -histogram_pointwise:
                               nb_levels>0[%],_value0[%],_value1[%]

               Compute the histogram of each vector-valued point of selected images.
               If value range is set, the histogram is estimated only for values in the specified
               value range.
               Default values: 'value0=0%' and 'value1=100%'.

           -hough:
                               _width>0,_height>0,gradient_norm_voting={ 0 | 1 }

               Compute hough transform (theta,rho) of selected images.
               Default values: 'width=512', 'height=width' and 'gradient_norm_voting=1'.

           -ifftpolar:

               Compute  inverse   fourier   transform   of   selected   images,   from   centered
       magnitude/phase images.

           -isophotes:
                               _nb_levels>0

               Render isophotes of selected images on a transparent background.
               Default value: 'nb_levels=64'

           -label (+):
                               _tolerance>=0,is_high_connectivity={ 0 | 1 }

               Label connected components in selected images.
               Default values: 'tolerance=0' and 'is_high_connectivity=0'.

           -label_fg:
                               tolerance>=0,is_high_connectivity={ 0 | 1 }

               Label connected components for non-zero values (foreground) in selected images.
               Similar to '-label' except that 0-valued pixels are not labeled.
               Default value: 'is_high_connectivity=0'.

           -max_patch:
                               _patch_size>=1

               Return locations of maximal values in local patch-based neighborhood of given size
       for selected
                 images.
               Default value: 'patch_size=16'.

           -min_patch:
                               _patch_size>=1

               Return locations of minimal values in local patch-based neighborhood of given size
       for selected
                 images.
               Default value: 'patch_size=16'.

           -minimal_path:
                               x0[%]>=0,y0[%]>=0,z0[%]>=0,x1[%]>=0,y1[%]>=0,z1[%]>=0,_is_high_connectivity={
       0
                                 | 1 }

               Compute minimal path between two points on selected potential maps.
               Default value: 'is_high_connectivity=0'.

           -mse (+):

               Compute MSE (Mean-Squared Error) matrix between selected images.

           -patches:
                               patch_width>0,patch_height>0,patch_depth>0,x0,y0,z0,_x1,_y1,_z1,...,_xN,_yN,_zN

               Extract N+1 patches from selected images, centered at specified locations.

           -patchmatch (+):
                               [patch_image],patch_width>=1,_patch_height>=1,_patch_depth>=1,_nb_iterations>=0,
                                 _nb_randoms>=0,_output_score={ 0 | 1 },_[guide]

               Estimate correspondence map between selected images  and  specified  patch  image,
       using
               the patchmatch algorithm, as described in the paper :
               "PatchMatch:  A Randomized Correspondence Algorithm for Structural Image Editing",
       by
               Connelly Barnes, Eli Shechtman, Adam Finkelstein, Dan B Goldman(2009).
               Each pixel of the returned correspondence map gives  the  location  (p,q)  of  the
       closest patch in
               the  specified  patch  image.  If  'output_score=1',  the  third channel gives the
       corresponding
               matching score for each patch as well.
               Default values:  'patch_height=patch_width',  'patch_depth=1',  'nb_iterations=5',
       'nb_randoms=5',
                 'output_score=0' and 'guide=(undefined)'.

           -plot2value:

               Retrieve values from selected 2d graph plots.

           -pointcloud:
                               _type  =  {  -X=-X-opacity  |  0=binary  |  1=cumulative | 2=label
       },_width,_height>0,
                                 _depth>0

               Convert a Nx1, Nx2, Nx3 or NxM image as a point cloud in  a  1d/2d  or  3d  binary
       image.
               If 'M'>3, the 3-to-M lines sets the (M-3)-dimensional color at each point.
               Parameters 'width','height' and 'depth' are related to the size of the final image
       :
               - If set to 0, the size is automatically set along the specified axis.
               - If set to N>0, the size along the specified axis is N.
               - If set to N<0, the size along the specified axis is at most N.
               Points  with  coordinates   that   are   negative   or   higher   than   specified
       ('width','height','depth')
               are not plotted.
               Default values: 'type=0' and 'max_width=max_height=max_depth=0'.

           -psnr:
                               _max_value

               Compute PSNR (Peak Signal-to-Noise Ratio) matrix between selected images.
               Default value: 'max_value=255'.

           -segment_watershed:
                               _threshold>=0

               Apply watershed segmentation on selected images.
               Default values: 'threshold=2'.

           -skeleton:
                               _smoothness[%]>=0

               Compute skeleton of binary shapes using distance transform.
               Default value: 'smoothness=0'.

           -ssd_patch:
                               [patch],_use_fourier={  0 | 1 },_boundary_conditions={ 0=dirichlet
       | 1=neumann }

               Compute fields of SSD between selected images and specified patch.
               Argument 'boundary_conditions' is valid only when 'use_fourier=0'.
               Default value: 'use_fourier=0' and 'boundary_conditions=0'.

           -thinning:

               Compute skeleton of binary shapes using morphological thinning
               (This is a quite slow iterative proces)

           -tones:
                               N>0

               Get N tones masks from selected images.

           -topographic_map:
                               _nb_levels>0,_smoothness

               Render selected images as topographic maps.
               Default values: 'nb_levels=16' and 'smoothness=2'.

           -variance_patch:
                               _patch_size>=1

               Compute variance of each images patch centered at (x,y), in selected images.
               Default value: 'patch_size=16'

        ** Image drawing:

           -arrow:
                               x0[%],y0[%],x1[%],y1[%],_thickness[%]>=0,_head_length[%]>=0,
                                 _head_thickness[%]>=0,_opacity,_pattern,_color1,...

               Draw specified arrow on selected images.
               'pattern' is an hexadecimal number starting with '0x' which can be omitted
               even if a color is specified. If a pattern is specified, the arrow is
               drawn outlined instead of filled.
               Default   values:    'thickness=1%',    'head_length=10%',    'head_thickness=3%',
       'opacity=1',
                 'pattern=(undefined)' and 'color1=0'.

           -axes:
                               x0,x1,y0,y1,_font_height>=0,_opacity,_pattern,_color1,...

               Draw xy-axes on selected images.
               'pattern' is an hexadecimal number starting with '0x' which can be omitted
               even if a color is specified.
               To draw only one x-axis at row Y, set both 'y0' and 'y1' to Y.
               To draw only one y-axis at column X, set both 'x0' and 'x1' to X.
               Default   values:   'font_height=14',   'opacity=1',   'pattern=(undefined)'   and
       'color1=0'.

           -ball:
                               _size>0,
       _R,_G,_B,0<=_specular_light<=8,0<=_specular_size<=8,_shadow>=0

               Input a 2d RGBA colored ball sprite.
               Default   values:   'size=64',   'R=255',   'G=R',   'B=R',  'specular_light=0.8',
       'specular_size=1' and
                 'shading=1.5'.

           -chessboard:
                               size1>0,_size2>0,_offset1,_offset2,_angle,_opacity,_color1,...,_color2,...

               Draw chessboard on selected images.
               Default   values:   'size2=size1',  'offset1=offset2=0',  'angle=0',  'opacity=1',
       'color1=0' and
                 'color2=255'.

           -cie1931:

               Draw CIE-1931 chromaticity diagram on selected images.

           -circle:
                               x[%],y[%],R[%],_opacity,_pattern,_color1,...

               Draw specified colored circle on selected images.
               A radius of '100%' stands for 'sqrt(width^2+height^2)'.
               'pattern' is an hexadecimal number starting with '0x' which can be omitted
               even if a color is specified. If a pattern is specified, the circle is
               drawn outlined instead of filled.
               Default values: 'opacity=1', 'pattern=(undefined)' and 'color1=0'.

           -ellipse (+):
                               x[%],y[%],R[%],r[%],_angle,_opacity,_pattern,_color1,...

               Draw specified colored ellipse on selected images.
               A radius of '100%' stands for 'sqrt(width^2+height^2)'.
               'pattern' is an hexadecimal number starting with '0x' which can be omitted
               even if a color is specified. If a pattern is specified, the ellipse is
               drawn outlined instead of filled.
               Default values: 'opacity=1', 'pattern=(undefined)' and 'color1=0'.

           -flood (+):
                               x[%],_y[%],_z[%],_tolerance>=0,_is_high_connectivity={   0   |   1
       },_opacity,_color1,
                                 ...

               Flood-fill selected images using specified value and tolerance.
               Default  values: 'y=z=0', 'tolerance=0', 'is_high_connectivity=0', 'opacity=1' and
       'color1=0'.

           -gaussian:
                               _sigma1[%],_sigma2[%],_angle

               Draw a centered gaussian on selected images, with  specified  standard  deviations
       and orientation.
               Default values: 'sigma1=3', 'sigma2=sigma1' and 'angle=0'.

           -graph (+):
                               [function_image],_plot_type,_vertex_type,_ymin,_ymax,_opacity,_pattern,_color1,.
                                 .. |
                               'formula',_resolution>=0,_plot_type,_vertex_type,_xmin,xmax,_ymin,_ymax,
                                 _opacity,_pattern,_color1,...

               Draw specified function graph on selected images.
               'plot_type' can be { 0=none | 1=lines | 2=splines | 3=bar }.
               'vertex_type' can be { 0=none | 1=points | 2,3=crosses | 4,5=circles | 6,7=squares
       }.
               'pattern' is an hexadecimal number starting with '0x' which can be omitted
               even if a color is specified.
               Default values: 'plot_type=1', 'vertex_type=1', 'ymin=ymax=0 (auto)', 'opacity=1',
                 'pattern=(undefined)'
               and 'color1=0'.

           -grid:
                               size_x[%]>=0,size_y[%]>=0,_offset_x[%],_offset_y[%],_opacity,_pattern,_color1,..
                                 .

               Draw xy-grid on selected images.
               'pattern' is an hexadecimal number starting with '0x' which can be omitted
               even if a color is specified.
               Default  values:  'offset_x=offset_y=0',  'opacity=1',  'pattern=(undefined)'  and
       'color1=0'.

           -image (+):
                               [sprite],_x[%],_y[%],_z[%],_c[%],_opacity,_[sprite_mask],_max_opacity_mask

               Draw specified sprite image on selected images.
               (eq. to '-j').
               Default    values:   'x=y=z=c=0',   'opacity=1',   'sprite_mask=(undefined)'   and
       'max_opacity_mask=1'.

           -line (+):
                               x0[%],y0[%],x1[%],y1[%],_opacity,_pattern,_color1,...

               Draw specified colored line on selected images.
               'pattern' is an hexadecimal number starting with '0x' which can be omitted
               even if a color is specified.
               Default values: 'opacity=1', 'pattern=(undefined)' and 'color1=0'.

           -mandelbrot (+):
                               z0r,z0i,z1r,z1i,_iteration_max>=0,_is_julia={      0      |      1
       },_c0r,_c0i,_opacity

               Draw mandelbrot/julia fractal on selected images.
               Default values: 'iteration_max=100', 'is_julia=0', 'c0r=c0i=0' and 'opacity=1'.

           -marble:
                               _image_weight,_pattern_weight,_angle,_amplitude,_sharpness>=0,_anisotropy>=0,
                                 _alpha,_sigma,_cut_low>=0,_cut_high>=0

               Render marble like pattern on selected images.
               Default    values:    'image_weight=0.2',    'pattern_weight=0.1',     'angle=45',
       'amplitude=0',
                 'sharpness=0.4', 'anisotropy=0.8',
               'alpha=0.6', 'sigma=1.1' and 'cut_low=cut_high=0'.

           -maze:
                               _width>0,_height>0,_cell_size>0

               Input maze with specified size.

           -maze_mask:
                               _cellsize>0

               Input maze according to size and shape of selected mask images.
               Mask may contain disconnected shapes.

           -object3d (+):
                               [object3d],_x[%],_y[%],_z,_opacity,_rendering_mode,_is_double_sided={
       0 | 1 },
                                 _is_zbuffer={                0                |                1
       },_focale,_light_x,_light_y,_light_z,_specular_lightness,
                                 _specular_shininess

               Draw specified 3d object on selected images.
               (eq. to '-j3d').
               'rendering_mode'  can  be  {  0=dots  |  1=wireframe  |  2=flat  | 3=flat-shaded |
       4=gouraud-shaded |
                 5=phong-shaded }.
               Default values: 'x=y=z=0', 'opacity=1' and  'is_zbuffer=1'.  All  other  arguments
       take their
                 default values from the 3d environment variables.

           -pack_sprites:
                               _nb_scales>=0,0<=_min_scale<=100,_allow_rotation={   0=0   deg.  |
       1=180 deg. | 2=90
                                 deg. | 3=any },_spacing,_precision>=0,max_iterations>=0

               Try to randomly pack as many sprites as possible onto  the  'empty'  areas  of  an
       image.
               Sprites can be eventually rotated and scaled during the packing process.
               First selected image is the canvas that will be filled with the sprites.
               Its  last  channel  must  be  a  binary mask whose zero values represent potential
       locations for
                 drawing the sprites.
               All other selected images represent the sprites considered for packing.
               Their last channel must be a binary mask that represents the sprite shape (i.e.  a
       8-connected
                 component).
               The  order  of  sprite packing follows the order of specified sprites in the image
       list.
               Sprite packing is done on random locations and iteratively with decreasing scales.
               'nb_scales' sets the number of decreasing  scales  considered  for  all  specified
       sprites to be
                 packed.
               'min_scale'  (in  %)  sets the minimal size considered for packing (specified as a
       percentage of
                 the original sprite size).
               'spacing' can be positive or negative.
               'precision' tells about the desired number of  failed  trials  before  ending  the
       filling process.
               Default  values:  'nb_scales=5',  'min_scale=25', 'allow_rotation=3', 'spacing=1',
       'precision=7'
                 and 'max_iterations=256'.

           -piechart:
                               label_height>=0,label_R,label_G,label_B,"label1",value1,R1,G1,B1,...,"labelN",
                                 valueN,RN,GN,BN

               Draw pie chart on selected (RGB) images.

           -plasma (+):
                               _alpha,_beta,_scale>=0

               Draw a random colored plasma fractal on selected images.
               This command implements the so-called 'Diamond-Square' algorithm.
               Default values: 'alpha=1', 'beta=1' and 'scale=8'.

           -point (+):
                               x[%],y[%],_z[%],_opacity,_color1,...

               Set specified colored pixel on selected images.
               Default values: 'z=0', 'opacity=1' and 'color1=0'.

           -polka_dots:
                               diameter>=0,_density,_offset1,_offset2,_angle,_aliasing,_shading,_opacity,
                                 _color,...

               Draw dots pattern on selected images.
               Default  values:  'density=20',  'offset1=offset2=50',  'angle=0',  'aliasing=10',
       'shading=1',
                 'opacity=1' and 'color=255'.

           -polygon (+):
                               N>=1,x1[%],y1[%],...,xN[%],yN[%],_opacity,_pattern,_color1,...

               Draw specified colored N-vertices polygon on selected images.
               'pattern' is an hexadecimal number starting with '0x' which can be omitted
               even if a color is specified. If a pattern is specified, the polygon is
               drawn outlined instead of filled.
               Default values: 'opacity=1', 'pattern=(undefined)' and 'color1=0'.

           -quiver:
                               [function_image],_sampling[%]>0,_factor>=0,_is_arrow={   0   |   1
       },_opacity,_color1,
                                 ...

               Draw specified 2d vector/orientation field on selected images.
               Default   values:   'sampling=5%',    'factor=1',    'is_arrow=1',    'opacity=1',
       'pattern=(undefined)'
               and 'color1=0'.

           -rectangle:
                               x0[%],y0[%],x1[%],y1[%],_opacity,_pattern,_color1,...

               Draw specified colored rectangle on selected images.
               'pattern' is an hexadecimal number starting with '0x' which can be omitted
               even if a color is specified. If a pattern is specified, the rectangle is
               drawn outlined instead of filled.
               Default values: 'opacity=1', 'pattern=(undefined)' and 'color1=0'.

           -rorschach:
                               'smoothness[%]>=0','mirroring={ 0=none | 1=x | 2=y | 3=xy }

               Render rorschach-like inkblots on selected images.
               Default values: 'smoothness=5%' and 'mirroring=1'.

           -sierpinski:
                               recursion_level>=0

               Draw Sierpinski triangle on selected images.
               Default value: 'recursion_level=7'.

           -spiralbw:

               Draw (squared) spiral on selected images.

           -spline:
                               x0[%],y0[%],u0[%],v0[%],x1[%],y1[%],u1[%],v1[%],_nb_vertices>=2,_opacity,
                                 _color1,...

               Draw specified colored spline curve on selected images (cubic hermite spline).
               Default values: 'nb_vertices=256', 'opacity=1' and 'color1=0'.

           -tetraedron_shade:
                               x0,y0,z0,x1,y1,z1,x2,y2,z2,x3,y3,z3,R0,G0,B0,...,R1,G1,B1,...,R2,G2,B2,...,R3,
                                 G3,B3,...

               Draw tetraedron with interpolated colors on selected (volumetric) images.

           -text (+):
                               text,_x[%],_y[%],_font_height[%]>=0,_opacity,_color1,...

               Draw specified colored text string on selected images.
               (eq. to '-t').
               Exact  pre-defined  sizes  are '13','23','53' and '103'. Using these sizes ensures
       you draw binary
                 letters without anti-aliasing.
               Any other font size is interpolated from an exact size (the upper when possible).
               Specifying an empty target image resizes it to new dimensions such that the  image
       contains
               the entire text string.
               Default values: 'opacity=1' and 'color1=0'.

           -text_outline:
                               text,_x[%],_y[%],_font_height>0,_outline>=0,_opacity,_color1,...

               Draw specified colored and outlined text string on selected images.
               Default   values:   'x=y=2',   'font_height=13',   'outline=2',   'opacity=1'  and
       'color1=255'.

           -triangle_shade:
                               x0,y0,x1,y1,x2,y2,R0,G0,B0,...,R1,G1,B1,...,R2,G2,B2,...

               Draw triangle with interpolated colors on selected images.

           -truchet:
                               _scale>0,_radius>=0,_pattern_type={ 0=straight | 1=curved }

               Fill selected images with random truchet patterns.
               Default values: 'scale=32', 'radius=5' and 'pattern_type=1'.

           -turbulence:
                               _radius>0,_octaves={1,2,3...,12},_alpha>0,_difference={-10,10},_mode={0,1,2,3}

               Render fractal noise or turbulence on selected images.
               Default values: 'radius=32', 'octaves=6', 'alpha=3', 'difference=0' and 'mode=0'.

           -yinyang:

               Draw a yin-yang symbol on selected images.

        ** Matrix computation:

           -dijkstra (+):
                               starting_node>=0,ending_node>=0

               Compute  minimal  distances  and  pathes  from specified adjacency matrices by the
       Dijkstra
                 algorithm.

           -eigen (+):

               Compute the eigenvalues and eigenvectors of selected symmetric matrices or  matrix
       fields.
               If one selected image has 3 or 6 channels, it is regarded as a field of 2x2 or 3x3
       symmetric
                 matrices,
               whose eigen elements are computed at each point of the field.

           -invert (+):

               Compute the inverse of the selected matrices.

           -solve (+):
                               [image]

               Solve linear system AX = B for selected B-matrices and specified A-matrix.
               If the system is under- or over-determined, the least square solution is returned.

           -svd (+):

               Compute SVD decomposition of selected matrices.

           -transpose:

               Transpose selected matrices.

           -trisolve (+):
                               [image]

               Solve tridiagonal system AX = B for selected B-vectors and  specified  tridiagonal
       A-matrix.
               Tridiagonal  matrix must be stored as a 3 column vector, where 2nd column contains
       the
               diagonal coefficients, while 1st and  3rd  columns  contain  the  left  and  right
       coefficients.

        ** 3d rendering:

           -add3d (+):
                               tx,_ty,_tz |
                               [object3d] |
                               (no arg)

               Shift  selected  3d objects with specified displacement vector, or merge them with
       specified
               3d object, or merge all selected 3d objects together.
               (eq. to '-+3d').
               Default values: 'ty=tz=0'.

           -animate3d:
                               _width>0,_height>0,_angle_dx,_angle_dy,_angle_dz,_zoom_factor>=0,_filename

               Animate selected 3d objects in a window.
               If  argument  'filename'  is  provided,  each frame of the animation is saved as a
       numbered filename.
               Default   values:   'width=640',   'height=480',    'angle_dx=0',    'angle_dy=1',
       'angle_dz=0',
                 'zoom_factor=1' and 'filename=(undefined)'.

           -apply_camera3d:
                               pos_x,pos_y,pos_z,target_x,target_y,target_z,up_x,up_y,up_z

               Apply 3d camera matrix to selected 3d objects.
               Default  values: 'target_x=0', 'target_y=0', 'target_z=0', 'up_x=0', 'up_y=-1' and
       'up_z=0'.

           -array3d:
                               size_x>=1,_size_y>=1,_size_z>=1,_offset_x[%],_offset_y[%],_offset_y[%]

               Duplicate a 3d object along the X,Y and Z axes.
               Default values: 'size_y=1', 'size_z=1' and 'offset_x=offset_y=offset_z=100%'.

           -arrow3d:
                               x0,y0,z0,x1,y1,z1,_radius[%]>=0,_head_length[%]>=0,_head_radius[%]>=0

               Input 3d arrow with specified starting and ending 3d points.
               Default values: 'radius=5%', 'head_length=25%' and 'head_radius=15%'.

           -axes3d:
                               _size_x,_size_y,_size_z,_font_size>0,_label_x,_label_y,_label_z

               Input 3d axes with specified sizes along the x,y and z orientations.
               Default values: 'size_x=size_y=size_z=1', 'font_size=23', 'label_x=X', 'label_y=Y'
       and
                 'label_z=Z'.

           -box3d:
                               _size_x,_size_y,_size_z

               Input 3d box at (0,0,0), with specified geometry.
               Default values: 'size_x=1' and 'size_z=size_y=size_x'.

           -center3d:

               Center selected 3d objects at (0,0,0).
               (eq. to '-c3d').

           -circle3d:
                               _x0,_y0,_z0,_radius>=0

               Input 3d circle at specified coordinates.
               Default values: 'x0=y0=z0=0' and 'radius=1'.

           -circles3d:
                               _radius>=0,_is_filled={ 0 | 1 }

               Convert specified 3d objects to sets of 3d circles with specified radius.
               Default values: 'radius=1' and 'is_filled=1'.

           -color3d (+):
                               R,_G,_B,_opacity

               Set color and opacity of selected 3d objects.
               (eq. to '-col3d').
               Default value: 'B=G=R' and 'opacity=(undefined)'.

           -colorcube3d:

               Input 3d color cube.

           -cone3d:
                               _radius,_height,_nb_subdivisions>0

               Input 3d cone at (0,0,0), with specified geometry.
               Default value: 'radius=1','height=1' and 'nb_subdivisions=24'.

           -cubes3d:
                               _size>=0

               Convert specified 3d objects to sets of 3d cubes with specified size.
               Default value: 'size=1'.

           -cup3d:
                               _resolution>0

               Input 3d cup object.

           -cylinder3d:
                               _radius,_height,_nb_subdivisions>0

               Input 3d cylinder at (0,0,0), with specified geometry.
               Default value: 'radius=1','height=1' and 'nb_subdivisions=24'.

           -delaunay3d:

               Generate 3d delaunay triangulations from selected images.
               One assumes that the selected input images are binary images containing the set of
       points to
                 mesh.
               The output 3d object is a mesh composed of non-oriented triangles.

           -distribution3d:

               Get 3d color distribution of selected images.

           -div3d (+):
                               factor |
                               factor_x,factor_y,_factor_z

               Scale selected 3d objects isotropically or anisotropically, with  the  inverse  of
       specified
               factors.
               (eq. to '-/3d').
               Default value: 'factor_z=0'.

           -double3d (+):
                               _is_double_sided={ 0 | 1 }

               Enable/disable double-sided mode for 3d rendering.
               (eq. to '-db3d').
               Default value: 'is_double_sided=1'.

           -elevation3d (+):
                               z-factor |
                               [elevation_map] |
                               'formula' |
                               (no arg)

               Build 3d elevation of selected images, with a specified elevation map.
               When  invoked  with  (no  arg) or 'z-factor', the elevation map is computed as the
       pointwise L2
                 norm of the
               pixel values. Otherwise, the elevation map is taken from the  specified  image  or
       formula.

           -empty3d:

               Input empty 3d object.

           -extrude3d:
                               _depth>0,_resolution>0,_smoothness[%]>=0

               Generate extruded 3d object from selected binary XY-profiles.
               Default values: 'depth=16', 'resolution=1024' and 'smoothness=0.5%'.

           -focale3d (+):
                               focale

               Set 3d focale.
               (eq. to '-f3d').
               Set 'focale' to 0 to enable parallel projection (instead of perspective).
               Set negative 'focale' will disable 3d sprite zooming.
               Default value: 'focale=700'.

           -gaussians3d:
                               _size>0,_opacity

               Convert selected 3d objects into set of 3d gaussian-shaped sprites.

           -gmic3d:

               Input a 3d G'MIC logo.

           -gyroid3d:
                               _resolution>0,_zoom

               Input 3d gyroid at (0,0,0), with specified resolution.
               Default values: 'resolution=32' and 'zoom=5'.

           -histogram3d:

               Get 3d color histogram of selected images.

           -image6cube3d:

               Generate 3d mapped cubes from 6-sets of selected images.

           -imageblocks3d:
                               _maximum_elevation,_smoothness[%]>=0

               Generate 3d blocks from selected images.
               Transparency of selected images is taken into account.
               Default values: 'maximum_elevation=10' and 'smoothness=0'.

           -imagecube3d:

               Generate 3d mapped cubes from selected images.

           -imageplane3d:

               Generate 3d mapped planes from selected images.

           -imagepyramid3d:

               Generate 3d mapped pyramides from selected images.

           -imagerubik3d:
                               _xy_tiles>=1,0<=xy_shift<=100,0<=z_shift<=100

               Generate 3d mapped rubik's cubes from selected images.
               Default values: 'xy_tiles=3', 'xy_shift=5' and 'z_shift=5'.

           -imagesphere3d:
                               _resolution1>=3,_resolution2>=3

               Generate 3d mapped sphere from selected images.
               Default values: 'resolution1=32' and 'resolutions2=16'.

           -isoline3d (+):
                               isovalue[%] |
                               'formula',value,_x0,_y0,_x1,_y1,_size_x>0[%],_size_y>0[%]

               Extract  3d  isolines  with specified value from selected images or from specified
       formula.
               Default values: 'x0=y0=-3', 'x1=y1=3' and 'size_x=size_y=256'.

           -isosurface3d (+):
                               isovalue[%] |
                               'formula',value,_x0,_y0,_z0,_x1,_y1,_z1,_size_x>0[%],_size_y>0[%],_size_z>0[%]

               Extract 3d isosurfaces with specified value from selected images or from specified
       formula.
               Default values: 'x0=y0=z0=-3', 'x1=y1=z1=3' and 'size_x=size_y=size_z=32'.

           -label3d:
                               "text",font_height>=0,_opacity,_color1,...

               Generate 3d text label.
               Default values: 'font_height=13', 'opacity=1' and 'color=255,255,255'.

           -label_points3d:
                               _label_size>0,_opacity

               Add a numbered label to all vertices of selected 3d objects.
               Default values: 'label_size=13' and 'opacity=0.8'.

           -lathe3d:
                               _resolution>0,_smoothness[%]>=0,_max_angle>=0

               Generate 3d object from selected binary XY-profiles.
               Default values: 'resolution=128', 'smoothness=0.5%' and 'max_angle=361'.

           -light3d (+):
                               position_x,position_y,position_z |
                               [texture] |
                               (no arg)

               Set the light coordinates or the light texture for 3d rendering.
               (eq. to '-l3d').
               (no arg) resets the 3d light to default.

           -line3d:
                               x0,y0,z0,x1,y1,z1

               Input 3d line at specified coordinates.

           -lissajous3d:
                               resolution>1,a,A,b,B,c,C

               Input                    3d                    lissajous                    curves
       (x(t)=sin(a*t+A*2*pi),y(t)=sin(b*t+B*2*pi),z(t)=sin(c*t+C*2*pi)).
               Default values: 'resolution=1024', 'a=2', 'A=0', 'b=1', 'B=0', 'c=0' and 'C=0'.

           -mode3d (+):
                               _mode

               Set static 3d rendering mode.
               (eq. to '-m3d').
               'mode' can be { -1=bounding-box | 0=dots | 1=wireframe | 2=flat | 3=flat-shaded |
                 4=gouraud-shaded | 5=phong-shaded }.");
               Bounding-box mode ('mode==-1') is active only for the interactive 3d viewer.
               Default value: 'mode=4'.

           -moded3d (+):
                               _mode

               Set dynamic 3d rendering mode for interactive 3d viewer.
               (eq. to '-md3d').
               'mode' can be { -1=bounding-box | 0=dots | 1=wireframe | 2=flat | 3=flat-shaded |
                 4=gouraud-shaded | 5=phong-shaded }.
               Default value: 'mode=-1'.

           -mul3d (+):
                               factor |
                               factor_x,factor_y,_factor_z

               Scale  selected  3d  objects  isotropically  or  anisotropically,  with  specified
       factors.
               (eq. to '-*3d').
               Default value: 'factor_z=0'.

           -normalize3d:

               Normalize selected 3d objects to unit size.
               (eq. to '-n3d').

           -opacity3d (+):
                               _opacity

               Set opacity of selected 3d objects.
               (eq. to '-o3d').
               Default value: 'opacity=1'.

           -parametric3d:
                               _x(a,b),_y(a,b),_z(a,b),_amin,_amax,_bmin,_bmax,_res_a>0,_res_b>0,_res_x>0,
                                 _res_y>0,_res_z>0,_smoothness>=0,_isovalue>=0

               Input 3d object from specified parametric surface (x(a,b),y(a,b),z(a,b)).
               Default    values:   'x=(2+cos(b))*sin(a)',   'y=(2+cos(b))*cos(a)',   'c=sin(b)',
       'amin=-pi',
                 'amax='pi', 'bmin=-pi', 'bmax='pi',
               'res_a=512',    'res_b=res_a',    'res_x=64',    'res_y=res_x',     'res_z=res_y',
       'smoothness=2%' and
                 'isovalue=10%'.

           -pca_patch3d:
                               _patch_size>0,_M>0,_N>0,_normalize_input={       0       |       1
       },_normalize_output={ 0 | 1 },
                                 _lambda_xy

               Get 3d patch-pca representation of selected images.
               The 3d patch-pca is estimated from M patches on the input image, and displayed  as
       a cloud of N
                 3d points.
               Default   values:   'patch_size=7',   'M=1000',   'N=3000',   'normalize_input=1',
       'normalize_output=0',
                 and 'lambda_xy=0'.

           -plane3d:
                               _size_x,_size_y,_nb_subdivisions_x>0,_nb_subdisivions_y>0

               Input 3d plane at (0,0,0), with specified geometry.
               Default         values:          'size_x=1',          'size_y=size_x'          and
       'nb_subdivisions_x=nb_subdivisions_y=24'.

           -point3d:
                               x0,y0,z0

               Input 3d point at specified coordinates.

           -pointcloud3d:

               Convert selected planar or volumetric images to 3d point clouds.

           -pose3d:
                               p1,...,p12

               Apply 3d pose matrix to selected 3d objects.

           -primitives3d (+):
                               mode

               Convert primitives of selected 3d objects.
               (eq. to '-p3d').
               'mode' can be { 0=points | 1=segments | 2=non-textured }.

           -projections3d:
                               _x[%],_y[%],_z[%],_is_bounding_box={ 0 | 1 }

               Generate 3d xy,xz,yz projection planes from specified volumetric images.

           -pyramid3d:
                               width,height

               Input 3d pyramid at (0,0,0), with specified geometry.

           -quadrangle3d:
                               x0,y0,z0,x1,y1,z1,x2,y2,z2,x3,y3,z3

               Input 3d quadrangle at specified coordinates.

           -random3d:
                               nb_points>=0

               Input random 3d point cloud in [0,1]^3.

           -reverse3d (+):

               Reverse primitive orientations of selected 3d objects.
               (eq. to '-rv3d').

           -rotate3d (+):
                               u,v,w,angle

               Rotate selected 3d objects around specified axis with specified angle (in deg.).
               (eq. to '-r3d').

           -rotation3d:
                               u,v,w,angle

               Input 3x3 rotation matrix with specified axis and angle (in deg).

           -sierpinski3d:
                               _recursion_level>=0,_width,_height

               Input 3d Sierpinski pyramid.

           -size3d:

               Return bounding box size of the last selected 3d object.

           -skeleton3d:
                               _metric,_frame_type={  0=squares | 1=diamonds | 2=circles | 3=auto
       },
                                 _skeleton_opacity,_frame_opacity,_is_frame_wireframe={ 0 | 1 }

               Build 3d skeletal structure object from  2d  binary  shapes  located  in  selected
       images.
               'metric' can be { 0=chebyshev | 1=manhattan | 2=euclidean }.
               Default    values:    'metric=2',    'bones_type=3',    'skeleton_opacity=1'   and
       'frame_opacity=0.1'.

           -snapshot3d:
                               _size>0,_zoom>=0,_backgroundR,_backgroundG,_backgroundB,_backgroundA
       |
                               [background_image],zoom>=0

               Take 2d snapshots of selected 3d objects.
               Set 'zoom' to 0 to disable object auto-scaling.
               Default values: 'size=512', 'zoom=1' and '[background_image]=(default)'.

           -specl3d (+):
                               value>=0

               Set lightness of 3d specular light.
               (eq. to '-sl3d').
               Default value: 'value=0.15'.

           -specs3d (+):
                               value>=0

               Set shininess of 3d specular light.
               (eq. to '-ss3d').
               Default value: 'value=0.8'.

           -sphere3d (+):
                               radius,_nb_recursions>=0

               Input 3d sphere at (0,0,0), with specified geometry.
               Default value: 'nb_recursions=3'.

           -spherical3d:
                               _nb_azimuth>=3,_nb_zenith>=3,_radius_function(phi,theta)

               Input 3d spherical object at (0,0,0), with specified geometry.
               Default              values:              'nb_zenith=nb_azimut=64'             and
       'radius_function="abs(1+0.5*cos(3*phi)*sin(4*
                 theta))"'.

           -spline3d:
                               x0[%],y0[%],z0[%],u0[%],v0[%],w0[%],x1[%],y1[%],z1[%],u1[%],v1[%],w1[%],
                                 _nb_vertices>=2

               Input 3d spline with specified geometry.
               Default values: 'nb_vertices=128'.

           -split3d (+):
                               _keep_shared_data={ 0 | 1 }

               Split selected 3d objects into 6 feature vectors :
               { header, sizes, vertices, primitives, colors, opacities }.
               (eq. to '-s3d').
               To recreate the 3d object, append these 6 images along the y-axis.
               Default value: 'keep_shared_data=1'.

           -sprite3d:

               Convert selected images as 3d sprites.
               Selected image with alpha channels are managed.

           -sprites3d:
                               [sprite],_sprite_has_alpha_channel={ 0 | 1 }

               Convert selected 3d objects as a sprite cloud.
               Set  'sprite_has_alpha_channel'  to  1  to  make  the last channel of the selected
       sprite be a
                 transparency mask.
               Default value: 'mask_has_alpha_channel=0'.

           -star3d:
                               _nb_branches>0,0<=_thickness<=1

               Input 3d star at (0,0,0), with specified geometry.
               Default values: 'nb_branches=5' and 'thickness=0.38'.

           -streamline3d (+):
                               x[%],y[%],z[%],_L>=0,_dl>0,_interpolation,_is_backward={  0  |   1
       },_is_oriented={
                                 0 | 1 } |
                               'formula',x,y,z,_L>=0,_dl>0,_interpolation,_is_backward={ 0 | 1 },
                                 _is_oriented={ 0 | 1 }

               Extract 3d streamlines from selected vector fields or from specified formula.
               'interpolation'  can  be  { 0=nearest integer | 1=1st-order | 2=2nd-order | 3=4th-
       order }.
               Default values: 'dl=0.1', 'interpolation=2', 'is_backward=0' and 'is_oriented=0'.

           -sub3d (+):
                               tx,_ty,_tz

               Shift selected 3d objects with the opposite of specified displacement vector.
               (eq. to '--3d').
               Default values: 'ty=tz=0'.

           -superformula3d:
                               resolution>1,m>=1,n1,n2,n3

               Input 2d superformula curve as a 3d object.
               Default values: 'resolution=1024', 'm=8', 'n1=1', 'n2=5' and 'n3=8'.

           -text_pointcloud3d:
                               _"text1",_"text2",_smoothness

               Input 3d text pointcloud from the two specified strings.
               Default values: 'text1="text1"', 'text2="text2"' and 'smoothness=1'.

           -text3d:
                               text,_font_height>0,_depth>0,_smoothness

               Input a 3d text object from specified text.
               Default values: 'font_height=53', 'depth=10' and 'smoothness=1.5'.

           -texturize3d (+):
                               [ind_texture],_[ind_coords]

               Texturize selected 3d objects with specified texture and coordinates.
               (eq. to '-t3d').
               When '[ind_coords]' is omitted, default XY texture projection is performed.
               Default value: 'ind_coords=(undefined)'.

           -torus3d:
                               _radius1,_radius2,_nb_subdivisions1>2,_nb_subdivisions2>2

               Input 3d torus at (0,0,0), with specified geometry.
               Default   values:   'radius1=1',    'radius2=0.3',    'nb_subdivisions1=24'    and
       'nb_subdivisions2=12'.

           -triangle3d:
                               x0,y0,z0,x1,y1,z1,x2,y2,z2

               Input 3d triangle at specified coordinates.

           -volume3d:

               Transform selected 3d volumetric images as 3d parallelepipedic objects.

           -weird3d:
                               _resolution>0

               Input 3d weird object at (0,0,0), with specified resolution.
               Default value: 'resolution=32'.

        ** Program control:

           -apply_parallel:
                               "command"

               Apply  specified  command  on each of the selected images, by parallelizing it for
       all image of
                 the list.
               (eq. to '-ap').

           -apply_parallel_channels:
                               "command"

               Apply specified command on each of the selected images, by  parallelizing  it  for
       all channel of
                 the images independently.
               (eq. to '-apc').

           -apply_parallel_overlap:
                               "command",overlap[%],nb_threads={ 0=auto | 1 | 2 | 4 | 8 | 16 }

               Apply  specified  command  on  each of the selected images, by parallelizing it on
       'nb_threads'
                 overlapped sub-images.
               (eq. to '-apo').
               'nb_threads' must be a power of 2.
               Default values: 'overlap=0','nb_threads=0'.

           -apply_timeout:
                               "command",_timeout={ 0=no timeout | >0=with specified timeout  (in
       seconds) }

               Apply a command with a timeout.

           -check (+):
                               expression

               Evaluate specified expression and display an error message if evaluated to false.
               If  'expression'  is not evaluable, it is regarded as a filename and checked if it
       exists.

           -check3d (+):
                               _is_full_check={ 0 | 1 }

               Check validity of selected 3d vector objects, and display an error message
               if one of the selected image is not a valid 3d vector object.
               Full 3d object check is slower but more precise.
               Default value: 'is_full_check=1'.

           -continue (+):

               Go to end of current block 'repeat...done', 'do...while' or 'local...endlocal'.

           -break (+):

               Break current 'repeat...done', 'do...while' or 'local...endlocal' block.

           -do (+):

               Start a 'do...while' block.

           -done (+):

               End  a  'repeat...done'  block,  and  go  to  associated  '-repeat'  position,  if
       iterations remain.

           -elif (+):
                               boolean |
                               filename

               Start a 'elif...[else]...endif' block if previous '-if' was not verified
               and test if specified boolean is true, or if specified filename exists.
               'boolean' can be a float number standing for { 0=false | other=true }.

           -else (+):

               Execute following commands if previous '-if' or '-elif' conditions failed.

           -endif (+):

               End a 'if...[elif]...[else]...endif' block.

           -endlocal (+):

               End a 'local...endlocal' block.
               (eq. to '-endl').

           -error (+):
                               message

               Print specified error message on the standard error (stderr) and exit interpreter,
       except
               if error is caught by a '-onfail' command.
               Command selection (if any) stands for displayed call stack subset instead of image
       indices.

           -exec (+):
                               command

               Execute external command using a system call.
               The status value is then set to the error code returned by the system call.
               (eq. to '-x').

           -if (+):
                               boolean |
                               filename

               Start  a  'if...[elif]...[else]...endif'  block  and  test if specified boolean is
       true,
               or if specified filename exists.
               'boolean' can be a float number standing for { 0=false | other=true }.

           -local (+):

               Start a 'local...[onfail]...endlocal' block, with selected images.
               (eq. to '-l').

           -mutex (+):
                               indice,_action={ 0=unlock | 1=lock }

               Lock or unlock specified mutex for multi-threaded programming.
               A locked mutex can be unlocked only by the same thread. All mutexes  are  unlocked
       by default.
               'indice' designates the mutex indice, in [0,255].
               Default value: 'action=1'.

           -noarg (+):

               Used  in  a custom command, '-noarg' tells the command that its argument list have
       not been used
               finally, and so they must be evaluated next in the G'MIC pipeline, just as if  the
       custom
               command takes no arguments at all.
               Use  this command to write a custom command which can decide if it takes arguments
       or not.

           -onfail (+):

               Execute following commands when an  error  is  encountered  in  the  body  of  the
       'local...endlocal'
                 block.
               The status value is set with the corresponding error message.

           -parallel (+):
                               _wait_threads,"command1","command2",...

               Execute specified commands in parallel, each in a different thread.
               Parallel threads share the list of images.
               'wait_threads' can be { 0=when current environment ends | 1=immediately }.
               Default value: 'wait_threads=1'.

           -progress (+):
                               0<=value<=100 |
                               -1

               Set the progress indice of the current processing pipeline.
               This command is useful only when G'MIC is used by an embedding application.

           -quit (+):

               Quit interpreter.
               (eq. to '-q').

           -repeat (+):
                               nb_iterations,_variable_name

               Start iterations of a 'repeat...done' block.

           -return (+):

               Return from current custom command.

           -rprogress:
                               0<=value<=100 | -1 | "command",0<=value_min<=100,0<=value_max<=100

               Set the progress indice of the current processing pipeline (relatively to
               previously defined progress bounds), or call the specified command with
               specified progress bounds.

           -skip (+):
                               item

               Do nothing but skip specified item.

           -status (+):
                               status_string

               Set the current status. Used to define a returning value in a function.
               (eq. to '-u').

           -while (+):
                               boolean |
                               filename

               End a 'do...while' block and go back to associated '-do'
               if specified boolean is true or if specified filename exists.
               'boolean' can be a float number standing for { 0=false | other=true }.

        ** Arrays, tiles and frames:

           -array:
                               M>0,_N>0,_expand_type={ 0=min | 1=max | 2=all }

               Create MxN array from selected images.
               Default values: 'N=M' and 'expand_type=0'.

           -array_fade:
                               M>0,_N>0,0<=_fade_start<=100,0<=_fade_end<=100,_expand_type={0=min
       | 1=max |
                                 2=all}

               Create MxN array from selected images.
               Default values: 'N=M', 'fade_start=60', 'fade_end=90' and 'expand_type=1'.

           -array_mirror:
                               N>=0,_dir={ 0=x | 1=y | 2=xy | 3=tri-xy },_expand_type={ 0 | 1 }

               Create 2^Nx2^N array from selected images.
               Default values: 'dir=2' and 'expand_type=0'.

           -array_random:
                               Ms>0,_Ns>0,_Md>0,_Nd>0

               Create MdxNd array of tiles from selected MsxNs source arrays.
               Default values: 'Ns=Ms', 'Md=Ms' and 'Nd=Ns'.

           -frame_blur:
                               _sharpness>0,_size>=0,_smoothness,_shading,_blur

               Draw RGBA-colored round frame in selected images.
               Default  values:  'sharpness=10',  'size=30',  'smoothness=0',   'shading=1'   and
       'blur=3%'.

           -frame_cube:
                               _depth>=0,_centering_x,_centering_y,_left_side={0=normal         |
       1=mirror-x |
                                 2=mirror-y | 3=mirror-xy},_right_side,_lower_side,_upper_side

               Insert 3d frames in selected images.
               Default values: 'depth=1', 'centering_x=centering_y=0' and 'left_side=right_side,
                 lower_side=upper_side=0'.

           -frame_fuzzy:
                               size_x[%]>=0,_size_y[%]>=0,_fuzzyness>=0,_smoothness[%]>=0,_R,_G,_B,_A

               Draw RGBA-colored fuzzy frame in selected images.
               Default values: 'size_y=size_x', 'fuzzyness=5', 'smoothness=1' and 'R=G=B=A=255'.

           -frame_painting:
                               _size[%]>=0,0<=_contrast<=1,_profile_smoothness[%]>=0,_R,_G,_B,
                                 _vignette_size[%]>=0,_vignette_contrast>=0,_defects_contrast>=0,
                                 0<=_defects_density<=100,_defects_size>=0,_defects_smoothness[%]>=0,
                                 _serial_number

               Add a painting frame to selected images.
               Default  values:  'size=10%',  'contrast=0.4',  'profile_smoothness=6%',  'R=225',
       'G=200', 'B=120',
                 'vignette_size=2%',        'vignette_contrast=400',       'defects_contrast=50',
       'defects_density=10',
                 'defects_size=1', 'defects_smoothness=0.5%' and 'serial_number=123456789'.

           -frame_pattern:
                               M>=3,_constrain_size={ 0 | 1 } |
                               M>=3,_[frame_image],_constrain_size={ 0 | 1 }

               Insert selected pattern frame in selected images.
               Default values: 'pattern=0' and 'constrain_size=0'.

           -frame_round:
                               _sharpness>0,_size>=0,_smoothness,_shading,_R,_G,_B,_A

               Draw RGBA-colored round frame in selected images.
               Default  values:  'sharpness=10',  'size=10',  'smoothness=0',   'shading=0'   and
       'R=G=B=A=255'.

           -frame_seamless:
                               frame_size>=0,_patch_size>0,_blend_size>=0,_frame_direction={
       0=inner (preserve
                                 image size) | 1=outer }

               Insert frame in selected images, so that tiling the  resulting  image  makes  less
       visible seams.
               Default values: 'patch_size=7', 'blend_size=5' and 'frame_direction=1'.

           -frame_x:
                               size_x[%],_col1,...,_colN

               Insert colored frame along the x-axis in selected images.
               Default values: 'col1=col2=col3=255' and 'col4=255'.

           -frame_xy:
                               size_x[%],_size_y[%],_col1,...,_colN

               Insert colored frame along the x-axis in selected images.
               Default values: 'size_y=size_x', 'col1=col2=col3=255' and 'col4=255'.
               (eq. to '-frame').

           -frame_xyz:
                               size_x[%],_size_y[%],_size_z[%]_col1,...,_colN

               Insert colored frame along the x-axis in selected images.
               Default values: 'size_y=size_x=size_z', 'col1=col2=col3=255' and 'col4=255'.

           -frame_y:
                               size_y[%],_col1,...,_colN

               Insert colored frame along the y-axis in selected images.
               Default values: 'col1=col2=col3=255' and 'col4=255'.

           -img2ascii:
                               _charset,_analysis_scale>0,_analysis_smoothness[%]>=0,_synthesis_scale>0,
                                 _output_ascii_filename

               Render selected images as binary ascii art.
               This command returns the corresponding the list of widths and  heights  (expressed
       as a number of
                 characters) for each selected image.
               Default      values:      'charset=[ascii      charset]',     'analysis_scale=16',
       'analysis_smoothness=20%',
                 'synthesis_scale=16' and '_output_ascii_filename=[undefined]'.

           -imagegrid:
                               M>0,_N>0

               Create MxN image grid from selected images.
               Default value: 'N=M'.

           -imagegrid_hexagonal:
                               _resolution>0,0<=_outline<=1

               Create hexagonal grids from selected images.
               Default values: 'resolution=32', 'outline=0.1' and 'is_antialiased=1'.

           -imagegrid_triangular:
                               pattern_width>=1,_pattern_height>=1,_pattern_type,0<=_outline_opacity<=1,
                                 _outline_color1,...

               Create triangular grids from selected images.
               'pattern  type'  can  be  {  0=horizontal  |  1=vertical  |  2=crossed  | 3=cube |
       4=decreasing |
                 5=increasing }.
               Default      values:      'pattern_width=24',      'pattern_height=pattern_width',
       'pattern_type=0',
                 'outline_opacity=0.1' and 'outline_color1=0'.

           -linearize_tiles:
                               M>0,_N>0

               Linearize MxN tiles on selected images.
               Default value: 'N=M'.

           -map_sprites:
                               _nb_sprites>=1,_allow_rotation={ 0=none | 1=90 deg. | 2=180 deg. }

               Map set of sprites (defined as the 'nb_sprites' latest images of the selection) to
       other
                 selected images,
               according to the luminosity of their pixel values.

           -pack:
                               is_ratio_constraint={ 0 | 1 },_sort_criterion

               Pack selected images into a single image.
               The returned status contains the list of new (x,y) offsets for each input image.
               Parameter 'is_ratio_constraint' tells if the resulting image must tend to a square
       image.
               Default values: 'is_ratio_constraint=0' and 'sort_criterion=max(w,h)'.

           -puzzle:
                               _width>0,_height>0,_M>=1,_N>=1,_curvature,_centering,_connectors_variability,
                                 _resolution>=1

               Input puzzle binary mask with specified size and geometry.
               Default values: 'width=height=512', 'M=N=5', 'curvature=0.5', 'centering=0.5',
                 'connectors_variability=0.5' and 'resolution=64'.

           -quadratize_tiles:
                               M>0,_N>0

               Quadratize MxN tiles on selected images.
               Default value: 'N=M'.

           -rotate_tiles:
                               angle,_M>0,N>0

               Apply MxN tiled-rotation effect on selected images.
               Default values: 'M=8' and 'N=M'.

           -shift_tiles:
                               M>0,_N>0,_amplitude

               Apply MxN tiled-shift effect on selected images.
               Default values: 'N=M' and 'amplitude=20'.

           -taquin:
                               M>0,_N>0,_remove_tile={ 0=none  |  1=first  |  2=last  |  3=random
       },_relief,
                                 _border_thickness[%],_border_outline[%],_outline_color

               Create MxN taquin puzzle from selected images.
               Default  value:  'N=M',  'relief=50', 'border_thickness=5', 'border_outline=0' and
       'remove_tile=0'.

           -tunnel:
                               _level>=0,_factor>0,_centering_x,_centering_y,_opacity,_angle

               Apply tunnel effect on selected images.
               Default   values:    'level=9',    'factor=80%',    'centering_x=centering_y=0.5',
       'opacity=1' and
                 'angle=0'

        ** Artistic:

           -boxfitting:
                               _min_box_size>=1,_max_box_size>=0,_initial_density>=0,_nb_attempts>=1

               Apply box fitting effect on selected images, as displayed the web page:
               [http://www.complexification.net/gallery/machines/boxFittingImg/]
               Default  values:  'min_box_size=1',  'max_box_size=0',  'initial_density=0.1'  and
       'nb_attempts=3'.

           -brushify:
                               [brush],_brush_nb_sizes>=1,0<=_brush_min_size_factor<=1,
                                 _brush_nb_orientations>=1,_brush_light_type,0<=_brush_light_strength<=1,
                                 _brush_opacity,_painting_density[%]>=0,0<=_painting_contours_coherence<=1,
                                 0<=_painting_orientation_coherence<=1,_painting_coherence_alpha[%]>=0,
                                 _painting_coherence_sigma[%]>=0,_painting_primary_angle,
                                 0<=_painting_angle_dispersion<=1

               Apply specified brush to create painterly versions of specified images.
               'brush_light_type' can be { 0=none | 1=flat | 2=darken | 3=lighten | 4=full }.
               Default      values:       'brush_nb_sizes=3',       'brush_min_size_factor=0.66',
       'brush_nb_orientations=12',
                 'brush_light_type=0',      'brush_light_strength=0.25',     'brush_opacity=0.8',
       'painting_density=20%',
                 'painting_contours_coherence=0.9', 'painting_orientation_coherence=0.9',
                 'painting_coherence_alpha=1',                      'painting_coherence_sigma=1',
       'painting_primary_angle=0',
                 'painting_angle_dispersion=0.2'

           -cartoon:
                               _smoothness,_sharpening,_threshold>=0,_thickness>=0,_color>=0,quantization>0

               Apply cartoon effect on selected images.
               Default     values:     'smoothness=3',     'sharpening=150',      'threshold=20',
       'thickness=0.25', 'color=1.5'
                 and 'quantization=8'.

           -color_ellipses:
                               _count>0,_radius>=0,_opacity>=0

               Add random color ellipses to selected images.
               Default values: 'count=400', 'radius=5' and 'opacity=0.1'.

           -cubism:
                               _density>=0,0<=_thickness<=50,_max_angle,_opacity,_smoothness>=0

               Apply cubism effect on selected images.
               Default  values:  'density=50',  'thickness=10', 'max_angle=75', 'opacity=0.7' and
       'smoothness=0'.

           -draw_whirl:
                               _amplitude>=0

               Apply whirl drawing effect on selected images.
               Default value: 'amplitude=100'.

           -drawing:
                               _amplitude>=0

               Apply drawing effect on selected images.
               Default value: 'amplitude=200'.

           -drop_shadow:
                               _offset_x[%],_offset_y[%],_smoothness[%]>=0,0<=_curvature<=1,_expand_size={
       0 |
                                 1 }

               Drop shadow behind selected images.
               Default  values: 'offset_x=20', 'offset_y=offset_x', 'smoothness=5', 'curvature=0'
       and
                 'expand_size=1'.

           -ellipsionism:
                               _R>0[%],_r>0[%],_smoothness>=0[%],_opacity,_outline>0,_density>0

               Apply ellipsionism filter to selected images.
               Default values: 'R=10', 'r=3',  'smoothness=1%',  'opacity=0.7',  'outlise=8'  and
       'density=0.6'.

           -fire_edges:
                               _edges>=0,0<=_attenuation<=1,_smoothness>=0,_threshold>=0,_nb_frames>0,
                                 _starting_frame>=0,frame_skip>=0

               Generate fire effect from edges of selected images.
               Default values: 'edges=0.7', 'attenuation=0.25', 'smoothness=0.5', 'threshold=25',
                 'nb_frames=1', 'starting_frame=20' and 'frame_skip=0'.

           -fractalize:
                               0<=detail_level<=1

               Randomly fractalize selected images.
               Default value: 'detail_level=0.8'

           -glow:
                               _amplitude>=0

               Add soft glow on selected images.
               Default value: 'amplitude=1%'.

           -halftone:
                               nb_levels>=2,_size_dark>=2,_size_bright>=2,_shape={   0=square   |
       1=diamond |
                                 2=circle   |   3=inv-square   |   4=inv-diamond  |  5=inv-circle
       },_smoothness[%]>=0

               Apply halftone dithering to selected images.
               Default  values:  'nb_levels=5',  'size_dark=8',  'size_bright=8',  'shape=5'  and
       'smoothnesss=0'.

           -hardsketchbw:
                               _amplitude>=0,_density>=0,_opacity,0<=_edge_threshold<=100,_is_fast={
       0 | 1 }

               Apply hard B&W sketch effect on selected images.
               Default values: 'amplitude=1000', 'sampling=3', 'opacity=0.1', 'edge_threshold=20'
       and
                 'is_fast=0'.

           -hearts:
                               _density>=0

               Apply heart effect on selected images.
               Default value: 'density=10'.

           -houghsketchbw:
                               _density>=0,_radius>0,0<=_threshold<=100,0<=_opacity<=1,_votesize[%]>0

               Apply hough B&W sketch effect on selected images.
               Default  values:  'density=8',  'radius=5',  'threshold=80',   'opacity=0.1'   and
       'votesize=100%'.

           -lightrays:
                               100<=_density<=0,_center_x[%],_center_y[%],_ray_length>=0,_ray_attenuation>=0

               Generate ray lights from the edges of selected images.
               Defaults values : 'density=50%', 'center_x=50%', 'center_y=50%',  'ray_length=0.9'
       and
                 'ray_attenuation=0.5'.

           -light_relief:
                               _ambient_light,_specular_lightness,_specular_size,_light_smoothness,_darkness,
                                 _xl,_yl,_zl,_zscale,_opacity_is_heightmap={ 0 | 1 }

               Apply relief light to selected images.
               Default     values(s)     :     'ambient_light=0.3',     'specular_lightness=0.5',
       'specular_size=0.2',
                 'darkness=0', 'xl=0.2', 'yl=zl=0.5',
               'zscale=1', 'opacity=1' and 'opacity_is_heightmap=0'.

           -mosaic:
                               0<=_density<=100

               Create random mosaic from selected images.
               Default values: 'density=30'.

           -old_photo:

               Apply old photo effect on selected images.

           -pencilbw:
                               _size>=0,_amplitude>=0

               Apply B&W pencil effect on selected images.
               Default values: 'size=0.3' and 'amplitude=60'.

           -pixelsort:
                               _ordering={   +   |   -   },_axis={   x   |  y  |  z  |  xy  |  yx
       },_[sorting_criterion],_[mask]

               Apply a 'pixel sorting' algorithm on selected images, as described in the page :
               http://satyarth.me/articles/pixel-sorting/

           -polaroid:
                               _size1>=0,_size2>=0

               Create polaroid effect in selected images.
               Default values: 'size1=10' and 'size2=20'.

           -polygonize:
                               _warp_amplitude>=0,_smoothness[%]>=0,_min_area[%]>=0,_resolution_x[%]>0,
                                 _resolution_y[%]>0

               Apply polygon effect on selected images.
               Default values: 'warp_amplitude=300', 'smoothness=2%', 'min_area=0.1%',
                 'resolution_x=resolution_y=10%'.

           -poster_edges:
                               0<=_edge_threshold<=100,0<=_edge_shade<=100,_edge_thickness>=0,
                                 _edge_antialiasing>=0,0<=_posterization_level<=15,_posterization_antialiasing>=0

               Apply poster edges effect on selected images.
               Default values: 'edge_threshold=40', 'edge_shade=5', 'edge_thickness=0.5',
                 'edge_antialiasing=10',               'posterization_level=12'               and
       'posterization_antialiasing=0'.

           -poster_hope:
                               _smoothness>=0

               Apply Hope stencil poster effect on selected images.
               Default value: 'smoothness=3'.

           -rodilius:
                               0<=_amplitude<=100,_0<=thickness<=100,_sharpness>=0,_nb_orientations>0,_offset,
                                 _color_mode={ 0=darker | 1=brighter }

               Apply rodilius (fractalius-like) filter on selected images.
               Default     values:     'amplitude=10',      'thickness=10',      'sharpness=400',
       'nb_orientations=7',
                 'offset=0' and 'color_mode=1'.

           -stained_glass:
                               _edges[%]>=0, shading>=0, is_thin_separators={ 0 | 1 }

               Generate stained glass from selected images.
               Default values: 'edges=40%', 'shading=0.2' and 'is_precise=0'.

           -stars:
                               _density[%]>=0,_depth>=0,_size>0,_nb_branches>=1,0<=_thickness<=1,
                                 _smoothness[%]>=0,_R,_G,_B,_opacity

               Add random stars to selected images.
               Default    values:    'density=10%',    'depth=1',   'size=32',   'nb_branches=5',
       'thickness=0.38',
                 'smoothness=0.5', 'R=G=B=200' and 'opacity=1'.

           -sketchbw:
                               _nb_orients>0,_start_angle,_angle_range>=0,_length>=0,_threshold>=0,_opacity,
                                 _bgfactor>=0,_density>0,_sharpness>=0,_anisotropy>=0,_smoothness>=0,
                                 _coherence>=0,_is_boost={ 0 | 1 },_is_curved={ 0 | 1 }

               Apply sketch effect to selected images.
               Default values: 'nb_orients=2', 'start_angle=45', 'angle_range=180',  'length=30',
       'threshold=1',
                  'opacity=0.03',
               'bgfactor=0', 'density=0.6', 'sharpness=0.1', 'anisotropy=0.6', 'smoothness=0.25',
                 'coherence=1', 'is_boost=0' and 'is_curved=1'.

           -sponge:
                               _size>0

               Apply sponge effect on selected images.
               Default value: 'size=13'.

           -stencil:
                               _radius[%]>=0,_smoothness>=0,_iterations>=0

               Apply stencil filter on selected images.
               Default values: 'radius=3', 'smoothness=1' and 'iterations=8'.

           -stencilbw:
                               _edges>=0,_smoothness>=0

               Apply B&W stencil effect on selected images.
               Default values: 'edges=15' and 'smoothness=10'.

           -tetris:
                               _scale>0

               Apply tetris effect on selected images.
               Default value: 'scale=10'.

           -warhol:
                               _M>0,_N>0,_smoothness>=0,_color>=0

               Create MxN Andy Warhol-like artwork from selected images.
               Default values: 'M=3', 'N=M', 'smoothness=2' and 'color=20'.

           -weave:
                               _density>=0,0<=_thickness<=100,0<=_shadow<=100,_shading>=0,_fibers_amplitude>=0,
                                 _fibers_smoothness>=0,_angle,-1<=_x_curvature<=1,-1<=_y_curvature<=1

               Apply weave effect to the selected images.
               'angle' can be { 0=0 deg. | 1=22.5 deg. | 2=45 deg. | 3=67.5 deg. }.
               Default   values:   'density=6',   'thickness=65',   'shadow=40',   'shading=0.5',
       'fibers_amplitude=0',
                 'fibers_smoothness=0', 'angle=0' and 'curvature_x=curvature_y=0'

           -whirls:
                               _texture>=0,_smoothness>=0,_darkness>=0,_lightness>=0

               Add random whirl texture to selected images.
               Default values: 'texture=3', 'smoothness=6', 'darkness=0.5' and 'lightness=1.8'.

        ** Warpings:

           -deform:
                               _amplitude>=0

               Apply random smooth deformation on selected images.
               Default value: 'amplitude=10'.

           -euclidean2polar:
                               _center_x[%],_center_y[%],_stretch_factor>0,_boundary={
       0=dirichlet | 1=neumann
                                 | 2=periodic }

               Apply euclidean to polar transform on selected images.
               Default values: 'center_x=center_y=50%', 'stretch_factor=1' and 'boundary=1'.

           -equirectangular2nadirzenith:

               Transform selected equirectangular images to nadir/zenith rectilinear projections.

           -fisheye:
                               _center_x,_center_y,0<=_radius<=100,_amplitude>=0

               Apply fish-eye deformation on selected images.
               Default values: 'x=y=50', 'radius=50' and 'amplitude=1.2'.

           -flower:
                               _amplitude,_frequency,_offset_r[%],_angle,_center_x[%],_center_y[%],_boundary={
                                 0=dirichlet | 1=neumann | 2=periodic }

               Apply flower deformation on selected images.
               Default   values:   'amplitude=30',   'frequency=6',   'offset_r=0',    'angle=0',
       'center_x=center_y=50%'
                 and 'boundary=2'.

           -kaleidoscope:
                               _center_x[%],_center_y[%],_radius,_angle,_boundary={ 0=dirichlet |
       1=neumann |
                                 2=periodic }

               Create kaleidoscope effect from selected images.
               Default   values:   'center_x=center_y=50%',    'radius=100',    'angle=30'    and
       'boundary=1'.

           -map_sphere:
                               _width>0,_height>0,_radius,_dilation>0,_fading>=0,_fading_power>=0

               Map selected images on a sphere.
               Default values: 'width=height=512', 'radius=100', 'dilation=0.5', 'fading=0' and
                 'fading_power=0.5'.

           -nadirzenith2equirectangular:

               Transform selected nadir/zenith rectilinear projections to equirectangular images.

           -polar2euclidean:
                               _center_x[%],_center_y[%],_stretch_factor>0,_boundary={
       0=dirichlet | 1=neumann
                                 | 2=periodic }

               Apply euclidean to polar transform on selected images.
               Default values: 'center_x=center_y=50%', 'stretch_factor=1' and 'boundary=1'.

           -raindrops:
                               _amplitude,_density>=0,_wavelength>=0,_merging_steps>=0

               Apply raindrops deformation on selected images.
               Default     values:     'amplitude=80','density=0.1',      'wavelength=1'      and
       'merging_steps=0'.

           -ripple:
                               _amplitude,_bandwidth,_shape={  0=bloc  |  1=triangle  |  2=sine |
       3=sine+ |
                                 4=random },_angle,_offset

               Apply ripple deformation on selected images.
               Default  values:  'amplitude=10',   'bandwidth=10',   'shape=2',   'angle=0'   and
       'offset=0'.

           -rotoidoscope:
                               _center_x[%],_center_y[%],_tiles>0,_smoothness[%]>=0,_boundary={
       0=dirichlet |
                                 1=neumann | 2=periodic }

               Create rotational kaleidoscope effect from selected images.
               Default values: 'cx=cy=50%', 'tiles=10', 'smoothness=1' and 'boundary=1'.

           -symmetrize:
                               _x[%],_y[%],_angle,_boundary={   0=dirichlet   |    1=neumann    |
       2=periodic },
                                 _is_antisymmetry={ 0 | 1 },_swap_sides={ 0 | 1 }

               Symmetrize selected image regarding specified axis.
               Default  values:  'x=y=50%',  'angle=90',  'boundary=1',  'is_antisymmetry=0'  and
       'swap_sides=0'.

           -transform_polar:
                               "expr_radius",_"expr_angle",_center_x[%],_center_y[%],_boundary={
       0=dirichlet |
                                 1=neumann }

               Apply user-defined transform on polar representation of selected images.
               Default  values:  'expr_radius=R-r',  'expr_rangle=a', 'center_x=center_y=50%' and
       'boundary=1'.

           -twirl:
                               _amplitude,_center_x[%],_center_y[%],_boundary={   0=dirichlet   |
       1=neumann |
                                 2=periodic }

               Apply twirl deformation on selected images.
               Default values: 'amplitude=1', 'center_x=center_y=50%' and 'boundary=1'.

           -warp_perspective:
                               _x-angle,_y-angle,_zoom>0,_x-center,_y-center,_boundary={
       0=dirichlet |
                                 1=neumann | 2=periodic }

               Warp selected images with perspective deformation.
               Default values: 'x-angle=1.5', 'y-angle=0', 'zoom=1',  'x-center=y-center=50'  and
       'boundary=2'.

           -water:
                               _amplitude,_smoothness>=0,_angle

               Apply water deformation on selected images.
               Default values: 'amplitude=30', 'smoothness=1.5' and 'angle=45'.

           -wave:
                               _amplitude>=0,_frequency>=0,_center_x,_center_y

               Apply wave deformation on selected images.
               Default values: 'amplitude=4', 'frequency=0.4' and 'center_x=center_y=50'.

           -wind:
                               _amplitude>=0,_angle,0<=_attenuation<=1,_threshold

               Apply wind effect on selected images.
               Default values: 'amplitude=20', 'angle=0', 'attenuation=0.7' and 'threshold=20'.

           -zoom:
                               _factor,_cx,_cy,_cz,_boundary={    0=dirichlet   |   1=neumann   |
       2=periodic }

               Apply zoom factor to selected images.
               Default values: 'factor=1', 'cx=cy=cz=0.5' and 'boundary=0'.

        ** Degradations:

           -cracks:
                               0<=_density<=100,_is_relief={ 0 | 1 },_opacity,_color1,...

               Draw random cracks on selected images with specified color.
               Default values: 'density=25', 'is_relief=0', 'opacity=1' and 'color1=0'.

           -light_patch:
                               _density>0,_darkness>=0,_lightness>=0

               Add light patches to selected images.
               Default values: 'density=10', 'darkness=0.9' and 'lightness=1.7'.

           -noise_hurl:
                               _amplitude>=0

               Add hurl noise to selected images.
               Default value: 'amplitude=10'.

           -pixelize:
                               _scale_x>0,_scale_y>0,_scale_z>0

               Pixelize selected images with specified scales.
               Default values: 'scale_x=20' and 'scale_y=scale_z=scale_x'.

           -scanlines:
                               _amplitude,_bandwidth,_shape={ 0=bloc  |  1=triangle  |  2=sine  |
       3=sine+ |
                                 4=random },_angle,_offset

               Apply ripple deformation on selected images.
               Default   values:   'amplitude=60',   'bandwidth=2',   'shape=0',   'angle=0'  and
       'offset=0'.

           -shade_stripes:
                               _frequency>=0,_direction={     0=horizontal      |      1=vertical
       },_darkness>=0,
                                 _lightness>=0

               Add shade stripes to selected images.
               Default values: 'frequency=5', 'direction=1', 'darkness=0.8' and 'lightness=2'.

           -shadow_patch:
                               _opacity>=0

               Add shadow patches to selected images.
               Default value: 'opacity=0.7'.

           -spread:
                               _dx>=0,_dy>=0,_dz>=0

               Spread pixel values of selected images randomly along x,y and z.
               Default values: 'dx=3', 'dy=dx' and 'dz=0'.

           -stripes_y:
                               _frequency>=0

               Add vertical stripes to selected images.
               Default value: 'frequency=10'.

           -texturize_canvas:
                               _amplitude>=0,_fibrousness>=0,_emboss_level>=0

               Add paint canvas texture to selected images.
               Default values: 'amplitude=20', 'fibrousness=3' and 'emboss_level=0.6'.

           -texturize_paper:

               Add paper texture to selected images.

           -vignette:
                               _strength>=0,0<=_radius_min<=100,0<=_radius_max<=100

               Add vignette effect to selected images.
               Default values: 'strength=100', 'radius_min=70' and 'radius_max=90'.

           -watermark_visible:
                               _text,0<_opacity<1,_size>0,_angle,_mode={    0=remove    |   1=add
       },_smoothness>=0

               Add or remove a  visible  watermark  on  selected  images  (value  range  must  be
       [0,255]).
               Default  values:  'text=(c) G'MIC', 'opacity=0.3', 'size=53', 'angle=25', 'mode=1'
       and
                 'smoothness=0'.

        ** Blending and fading:

           -blend:
                               [layer],blending_mode,0<=_opacity<=1,_selection_is={ 0=base-layers
       |
                                 1=top-layers } |
                               blending_mode,0<=_opacity<=1

               Blend  selected  G,GA,RGB  or RGBA images by specified layer or blend all selected
       images together,
                  using specified blending mode.
               'blending_mode' can be { add | alpha | and | average | blue  |  burn  |  darken  |
       difference |
               divide  | dodge | edges | exclusion | freeze | grainextract | grainmerge | green |
       hardlight |
               hardmix | hue | interpolation | lighten | lightness | linearburn |  linearlight  |
       luminance |
               multiply  |  negation  |  or  |  overlay | pinlight | red | reflect | saturation |
       seamless |
                 seamless_mixed |
               screen | shapeaverage | shapeaverage0 | softburn | softdodge | softlight | stamp |
       subtract |
                 value |
               vividlight | xor }.
               Default values: 'blending_mode=alpha', 'opacity=1' and 'selection_is=0'.

           -blend_edges:
                               smoothness[%]>=0

               Blend selected images togethers using 'edges' mode.

           -blend_fade:
                               [fading_shape]

               Blend selected images together using specified fading shape.

           -blend_median:

               Blend selected images together using 'median' mode.

           -blend_seamless:
                               _is_mixed_mode={ 0 | 1 },_inner_fading[%]>=0,_outer_fading[%]>=0

               Blend selected images using a seamless blending mode (Poisson-based).
               Default values: 'is_mixed=0', 'inner_fading=0' and 'outer_fading=100%'.

           -fade_diamond:
                               0<=_start<=100,0<=_end<=100

               Create diamond fading from selected images.
               Default values: 'start=80' and 'end=90'.

           -fade_linear:
                               _angle,0<=_start<=100,0<=_end<=100

               Create linear fading from selected images.
               Default values: 'angle=45', 'start=30' and 'end=70'.

           -fade_radial:
                               0<=_start<=100,0<=_end<=100

               Create radial fading from selected images.
               Default values: 'start=30' and 'end=70'.

           -fade_x:
                               0<=_start<=100,0<=_end<=100

               Create horizontal fading from selected images.
               Default values: 'start=30' and 'end=70'.

           -fade_y:
                               0<=_start<=100,0<=_end<=100

               Create vertical fading from selected images.
               Default values: 'start=30' and 'end=70'.

           -fade_z:
                               0<=_start<=100,0<=_end<=100

               Create transversal fading from selected images.
               Default values: 'start=30' and 'end=70'.

           -sub_alpha:
                               [base_image],_opacity_gain>=1

               Compute  the minimal alpha-channel difference (opposite of alpha blending) between
       the selected
                 images and the specified base image.
               The alpha difference A-B is defined as the image having minimal opacity, such that
                 alpha_blend(B,A-B) = A.
               Default value: 'opacity_gain=1'.

        ** Image sequences and videos:

           -animate:
                               filter_name,"param1_start,...,paramN_start","param1_end,...,paramN_end",
                                 nb_frames>=0,_output_frames={ 0 | 1 },_output_filename |
                               delay>0

               Animate  filter  from starting parameters to ending parameters or animate selected
       images
               in a display window.
               Default value: 'delay=30'.

           -apply_camera:
                               _"command",_camera_index>=0,_skip_frames>=0,_output_filename

               Apply specified command on live camera stream, and display it  on  display  window
       [0].
               Default  values:  'command=""', 'camera_index=0' (default camera), 'skip_frames=0'
       and
                 'output_filename=""'.

           -apply_files:
                               "filename_pattern",_"command",_first_frame>=0,_last_frame={ >=0  |
       -1=last },
                                 _frame_step>=1,_output_filename

               Apply a G'MIC command on specified input image files, in a streamed way.
               If  a  display  window  is  opened,  rendered  frames  are  displayed in it during
       processing.
               The output filename may have extension '.avi' (saved as a  video),  or  any  other
       usual image file
                 extension (saved as a sequence of images).
               Default    values:    'command=(undefined)',   'first_frame=0',   'last_frame=-1',
       'frame_step=1' and
                 'output_filename=(undefined)'.

           -apply_video:
                               video_filename,_"command",_first_frame>=0,_last_frame={   >=0    |
       -1=last },
                                 _frame_step>=1,_output_filename

               Apply  a  G'MIC  command  on  all  frames  of the specified input video file, in a
       streamed way.
               If a display window  is  opened,  rendered  frames  are  displayed  in  it  during
       processing.
               The  output  filename  may  have extension '.avi' (saved as a video), or any other
       usual image file
                 extension (saved as a sequence of images).
               Default values: 'first_frame=0', 'last_frame=-1', 'frame_step=1' and
                 'output_filename=(undefined)'.

           -average_files:
                               "filename_pattern",_first_frame>=0,_last_frame={  >=0  |   -1=last
       },_frame_step>=1,
                                 _output_filename

               Average specified input image files, in a streamed way.
               If  a  display  window  is  opened,  rendered  frames  are  displayed in it during
       processing.
               The output filename may have extension '.avi' (saved as a  video),  or  any  other
       usual image file
                 extension (saved as a sequence of images).
               Default values: 'first_frame=0', 'last_frame=-1', 'frame_step=1' and
                 'output_filename=(undefined)'.

           -average_video:
                               video_filename,_first_frame>=0,_last_frame={    >=0    |   -1=last
       },_frame_step>=1,
                                 _output_filename

               Average frames of specified input video file, in a streamed way.
               If a display window  is  opened,  rendered  frames  are  displayed  in  it  during
       processing.
               The  output  filename  may  have extension '.avi' (saved as a video), or any other
       usual image file
                 extension (saved as a sequence of images).
               Default values: 'first_frame=0', 'last_frame=-1', 'frame_step=1' and
                 'output_filename=(undefined)'.

           -fade_files:
                               "filename_pattern",_nb_inner_frames>0,_first_frame>=0,_last_frame={
       >=0 |
                                 -1=last },_frame_step>=1,_output_filename

               Generate a temporal fading from specified input image files, in a streamed way.
               If  a  display  window  is  opened,  rendered  frames  are  displayed in it during
       processing.
               The output filename may have extension 'avi' (saved as  a  video),  or  any  other
       usual image file
                 extension (saved as a sequence of images).
               Default    values:    'nb_inner_frames=10',    'first_frame=0',   'last_frame=-1',
       'frame_step=1' and
                 'output_filename=(undefined)'.

           -fade_video:
                               video_filename,_nb_inner_frames>0,_first_frame>=0,_last_frame={
       >=0 | -1=last },
                                 _frame_step>=1,_output_filename

               Create  a  temporal fading sequence from specified input video file, in a streamed
       way.
               If a display window  is  opened,  rendered  frames  are  displayed  in  it  during
       processing.
               Default    values:    'nb_inner_frames=10',    'first_frame=0',   'last_frame=-1',
       'frame_step=1' and
                 'output_filename=(undefined)'.

           -files2video:
                               "filename_pattern",_output_filename,_fps>0,_codec

               Convert several files into a single video file.
               Default values: 'output_filename=output.avi', 'fps=25' and 'codec=mp4v'.

           -median_files:
                               "filename_pattern",_first_frame>=0,_last_frame={  >=0  |   -1=last
       },_frame_step>=1,
                                 _frame_rows[%]>=1,_is_fast_approximation={ 0 | 1 }

               Compute the median frame of specified input image files, in a streamed way.
               If  a  display  window  is  opened,  rendered  frame  is  displayed  in  it during
       processing.
               Default values: 'first_frame=0', 'last_frame=-1', 'frame_step=1', 'frame_rows=20%'
       and
                 'is_fast_approximation=0'.

           -median_video:
                               video_filename,_first_frame>=0,_last_frame={    >=0    |   -1=last
       },_frame_step>=1,
                                 _frame_rows[%]>=1,_is_fast_approximation={ 0 | 1 }

               Compute the median of all frames of an input video file, in a streamed way.
               If a  display  window  is  opened,  rendered  frame  is  displayed  in  it  during
       processing.
               Default      values:     'first_frame=0',     'last_frame=-1',     'frame_step=1',
       'frame_rows=100%' and
                 'is_fast_approximation=1'.

           -morph:
                               nb_inner_frames>=1,_smoothness>=0,_precision>=0

               Create morphing sequence between selected images.
               Default values: 'smoothness=0.1' and 'precision=4'.

           -morph_files:
                               "filename_pattern",_nb_inner_frames>0,_smoothness>=0,_precision>=0,
                                 _first_frame>=0,_last_frame={        >=0        |        -1=last
       },_frame_step>=1,_output_filename

               Generate a temporal morphing from specified input image files, in a streamed way.
               If a display window  is  opened,  rendered  frames  are  displayed  in  it  during
       processing.
               The  output  filename  may  have extension '.avi' (saved as a video), or any other
       usual image file
                 extension (saved as a sequence of images).
               Default    values:    'nb_inner_frames=10',    'smoothness=0.1',    'precision=4',
       'first_frame=0',
                 'last_frame=-1', 'frame_step=1' and 'output_filename=(undefined)'.

           -morph_video:
                               video_filename,_nb_inner_frames>0,_smoothness>=0,_precision>=0,_first_frame>=0,
                                 _last_frame={ >=0 | -1=last },_frame_step>=1,_output_filename

               Generate a temporal morphing from specified input video file, in a streamed way.
               If a display window  is  opened,  rendered  frames  are  displayed  in  it  during
       processing.
               The  output  filename  may  have extension '.avi' (saved as a video), or any other
       usual image file
                 extension (saved as a sequence of images).
               Default    values:    'nb_inner_frames=10',    'smoothness=0.1',    'precision=4',
       'first_frame=0',
                 'last_frame=-1', 'frame_step=1' and 'output_filename=(undefined)'.

           -register_nonrigid:
                               [destination],_smoothness>=0,_precision>0,_nb_scale>=0

               Register  selected source images with specified destination image, using non-rigid
       warp.
               Default values: 'smoothness=0.2', 'precision=6' and 'nb_scale=0(auto)'.

           -register_rigid:
                               [destination],_smoothness>=0,_boundary={ 0=dirichlet | 1=neumann |
       2=periodic }

               Register selected source images with specified destination image, using rigid warp
       (shift).
               Default values: 'smoothness=1' and 'boundary=0'.

           -transition:
                               [transition_shape],nb_added_frames>=0,100>=shading>=0,_single_frame_only={
                                 -1=disabled | >=0 }

               Generate a transition sequence between selected images.
               Default values: 'shading=0' and 'single_frame_only=-1'.

           -transition3d:
                               _nb_frames>=2,_nb_xtiles>0,_nb_ytiles>0,_axis_x,_axis_y,_axis_z,_is_antialias={
                                 0 | 1 }

               Create 3d transition sequence between selected consecutive images.
               'axis_x', 'axis_y' and 'axis_z' can be set as mathematical expressions,  depending
       on 'x' and
                 'y'.
               Default  values:  'nb_frames=10', 'nb_xtiles=nb_ytiles=3', 'axis_x=1', 'axis_y=1',
       'axis_z=0' and
                 'is_antialias=1'.

           -video2files:
                               input_filename,_output_filename,_first_frame>=0,_last_frame={  >=0
       | -1=last },
                                 _frame_step>=1

               Split specified input video file into image files, one for each frame.
               First and last frames as well as step between frames can be specified.
               Default values: 'output_filename=frame.png', 'first_frame=0', 'last_frame=-1' and
                 'frame_step=1'.

        ** PINK-library operators:

           -output_pink3d:
                               filename

               Save  selected  images  as  P5-coded  PPM  files (PINK extension for 3d volumetric
       images).

           -pink:

               Pink wrapper name,p1,...,pn (requires the PINK library to be installed).
               (http://pinkhq.com/)
               prepares input, calls external "name input p1...pn output" and reads output (/tmp)

           -pink_grayskel:
                               _connectivity={ 4 | 8 | 6 | 26 }, _lambda=0

               (http://pinkhq.com/doxygen/grayskel_8c.html)
               Grayscale homotopic skeleton (requires the PINK library to be installed).
               Default values: 'connectivity=4' and 'lambda=0'.

           -pink_heightmaxima:
                               _connectivity={ 4 | 8 | 6 | 26 },_height=1

               (http://pinkhq.com/doxygen/heightmaxima_8c.html)
               Heightmaxima filtering (requires the PINK library to be installed).
               Default values: 'connectivity=4' and 'height=1'.

           -pink_heightminima:
                               _connectivity={ 4 | 8 | 6 | 26 },_height=1

               (http://pinkhq.com/doxygen/heightminima_8c.html)
               Heightminima filtering (requires the PINK library to be installed).
               Default values: 'connectivity=4' and 'height=1'.

           -pink_htkern:
                               _connectivity={ 4 | 8 | 6 | 26 }, _type={""|u}

               (http://pinkhq.com/doxygen/htkern_8c.html)
               (http://pinkhq.com/doxygen/htkernu_8c.html)
               Grayscale ultimate homotopic thinning/thickening without condition  (requires  the
       PINK library
                 to be installed).
               Default values: 'connectivity=4' and 'type=""'.

           -pink_lvkern:
                               _connectivity={ 4 | 8 | 6 | 26 }, _type={""|u}

               (http://pinkhq.com/doxygen/lvkern_8c.html)
               (http://pinkhq.com/doxygen/lvkernu_8c.html)
               Grayscale  ultimate  leveling  thinning/thickening without condition (requires the
       PINK library to
                 be installed).
               Default values: 'connectivity=4' and 'type=""'.

           -pink_reg_minima:
                               _connectivity={ 4 | 8 | 6 | 26 }

               (http://pinkhq.com/doxygen/minima_8c.html)
               Regional minima (requires the PINK library to be installed).
               Default values: 'connectivity=4'.

           -pink_skelcurv:
                               _prio={0|1|2|3|4|8|6|26},_connectivity={  4  |  8   |   6   |   26
       },_inhibit={""}

               (http://pinkhq.com/doxygen/skelcurv_8c.html)
               Curvilinear  binary  skeleton guided by a priority function or image (requires the
       PINK library
                 to be installed).
               Default values: 'prio=0', 'connectivity=4' and 'inhibit=""'.

           -pink_skelend:
                               _connectivity={ 4 | 8 | 6 | 26 },_n=0

               (http://pinkhq.com/doxygen/skelend_8c.html)
               Homotopic skeleton of a 2d or 3d binary image with dynamic detection of end points
       (requires
                 the PINK library to be installed).
               Default values: 'connectivity=4' and 'n=0'.

           -pink_skeleton:
                               _prio={0|1|2|3|4|8|6|26},_connectivity={   4   |   8   |  6  |  26
       },_inhibit={""}

               (http://pinkhq.com/doxygen/skeleton_8c.html)
               Ultimate binary skeleton guided by a priority image (requires the PINK library  to
       be installed).
               Default values: 'prio=0', 'connectivity=4' and 'inhibit=""'.

           -pink_skelpar:
                               _algorithm={0...29},_nsteps=_1,_inhibit=""

               (http://pinkhq.com/doxygen/skelpar_8c.html)
               Parallel binary skeleton (requires the PINK library to be installed).
               Default values: 'algorithm=4', 'nsteps=-1' and 'inhibit=""'.

           -pink_wshed:
                               _connectivity={ 4 | 8 | 6 | 26 },_inverse={ 0 | 1 },_height=0

               (http://pinkhq.com/doxygen/wshedtopo_8c.html)
               Watershed (requires the PINK library to be installed).
               Default values: 'connectivity=4', 'inverse=0' and 'height=0'.

        ** Convenience functions:

           -alert:
                               _title,_message,_label_button1,_label_button2,...

               Display an alert box and wait for user's choice.
               If a single image is in the selection, it is used as an icon for the alert box.
               Default values: 'title=[G'MIC Alert]' and 'message=This is an alert box.'.

           -arg:
                               n>=1,_arg1,...,_argN

               Return the n-th argument of the specified argument list.

           -arg2var:
                               variable_name,argument_1,...,argument_N

               For each i in [1...N], set 'variable_name$i=argument_i'.
               The  variable name should be global to make this command useful (i.e. starts by an
       underscore).

           -autocrop_coords:
                               value1,value2,... | auto

               Return coordinates (x0,y0,z0,x1,y1,z1) of the autocrop that could be performed  on
       the latest of
                 the selected images.
               Default value: 'auto'

           -average_color:

               Return the average color of the latest of the selected images.

           -basename:
                               file_path,_variable_name_for_folder

               Return the basename of a file path, and opt. its folder location.
               When specified 'variable_name_for_folder' must starts by an underscore
               (global variable accessible from calling function).

           -bin:
                               binary_int1,...

               Print specified binary integers into their octal, decimal, hexadecimal and string
                 representations.

           -bin2dec:
                               binary_int1,...

               Convert specified binary integers into their decimal representations.

           -dec:
                               decimal_int1,...

               Print specified decimal integers into their binary, octal, hexadecimal and string
                 representations.

           -dec2str:
                               decimal_int1,...

               Convert specifial decimal integers into its string representation.

           -dec2bin:
                               decimal_int1,...

               Convert specified decimal integers into their binary representations.

           -dec2hex:
                               decimal_int1,...

               Convert specified decimal integers into their hexadecimal representations.

           -dec2oct:
                               decimal_int1,...

               Convert specified decimal integers into their octal representations.

           -fact:
                               value

               Return the factorial of the specified value.

           -fibonacci:
                               N>=0

               Return the Nth number of the Fibonacci sequence.

           -file_mv:
                               filename_src,filename_dest

               Rename or move a file from a location $1 to another location $2.

           -file_rand:

               Return a random filename for storing temporary data.

           -file_rm:
                               filename

               Delete a file.

           -filename:
                               filename,_number1,_number2,...,_numberN

               Return a filename numbered with specified indices.

           -files (+):
                               _mode,path

               Return the list of files and/or subfolders from specified path.
               'path' can be eventually a matching pattern.
               'mode' can be { 0=files only | 1=folders only | 2=files + folders }.
               Add '3' to 'mode' to return full paths instead of filenames only.
               Default value: 'mode=5'.

           -fitratio_wh:
                               min_width,min_height,ratio_wh

               Return  a  2d  size 'width,height' which is bigger than 'min_width,min_height' and
       has the
                 specified w/h ratio.

           -fitscreen:
                               width,height,_depth,_minimal_size[%],_maximal_size[%]

               Return the 'ideal' size WxH for a window intended to display an image of specified
       size on
                 screen.
               Default values: 'depth=1', 'minimal_size=128' and 'maximal_size=85%'.

           -fps:

               Return  the  number of time this function is called per second, or -1 if this info
       is not yet
                 available.
               Useful to display the framerate when displaying animations.

           -gcd:
                               a,b

               Return the GCD (greatest common divisor) between a and b.

           -hex:
                               hexadecimal_int1,...

               Print specified hexadecimal integers into their binary, octal, decimal and string
                 representations.

           -hex2dec:
                               hexadecimal_int1,...

               Convert specified hexadecimal integers into their decimal representations.

           -hex2img:
                               "hexadecimal_string"

               Insert new image 1xN at the end of the list with values specified by the given
                 hexadecimal-encoded string.

           -hex2str:
                               hexadecimal_string

               Convert specified hexadecimal string into a string.

           -img2hex:

               Return representation of last image as an hexadecimal-encoded string.
               Input image must have values that are integers in [0,255].

           -img2str:

               Return the content of the latest of the selected image as a  special  G'MIC  input
       string.

           -img2text:
                               _line_separator

               Return text contained in a multi-line image.
               Default value: 'line_separator= '.

           -img82hex:

               Convert  selected  8bits-valued  vectors  into  their  hexadecimal representations
       (ascii-encoded).

           -hex2img8:

               Convert selected hexadecimal  representations  (ascii-encoded)  into  8bits-valued
       vectors.

           -is_3d:

               Return 1 if all of the selected image are 3d objects, 0 otherwise.

           -is_ext:
                               filename,_extension

               Return 1 if specified filename has a given extensioin.

           -is_image_arg:
                               string

               Return 1 if specified string looks like '[ind]'.

           -is_pattern:
                               string

               Return 1 if specified string looks like a drawing pattern '0x......'.

           -is_percent:
                               string

               Return 1 if specified string ends with a '%', 0 otherwise.

           -is_videofilename:

               Return 1 if extension of specified filename is typical from video files.

           -is_windows:

               Return 1 if current computer OS is Windows, 0 otherwise.

           -math_lib:

               Return  string  that  defines a set of several useful macros for the embedded math
       evaluator.

           -mad:

               Return the MAD (Maximum Absolute Deviation) of the last selected image.
               The MAD is defined as MAD = med_i|x_i-med_j(x_j)|

           -max_w:

               Return the maximal width between selected images.

           -max_h:

               Return the maximal height between selected images.

           -max_d:

               Return the maximal depth between selected images.

           -max_s:

               Return the maximal spectrum between selected images.

           -max_wh:

               Return the maximal wxh size of selected images.

           -max_whd:

               Return the maximal wxhxd size of selected images.

           -max_whds:

               Return the maximal wxhxdxs size of selected images.

           -med:

               Return the median value of the last selected image.

           -color_med:

               Return the median color value of the last selected image.

           -min_w:

               Return the minimal width between selected images.

           -min_h:

               Return the minimal height between selected images.

           -min_d:

               Return the minimal depth between selected images.

           -min_s:

               Return the minimal s size of selected images.

           -min_wh:

               Return the minimal wxh size of selected images.

           -min_whd:

               Return the minimal wxhxd size of selected images.

           -min_whds:

               Return the minimal wxhxdxs size of selected images.

           -normalize_filename:
                               filename

               Return a "normalized" version  of  the  specified  filename,  without  spaces  and
       capital letters.

           -oct:
                               octal_int1,...

               Print specified octal integers into their binary, decimal, hexadecimal and string
                 representations.

           -oct2dec:
                               octal_int1,...

               Convert specified octal integers into their decimal representations.

           -padint:
                               number,_size>0

               Return a integer with 'size' digits (eventually left-padded with '0').

           -path_gimp:

               Return  a  path to store GIMP configuration files for one user (whose value is OS-
       dependent).

           -path_tmp:

               Return a path to store temporary files (whose value is OS-dependent).

           -region_feature:
                               region_label,feature,_default_value

               Return feature for a specified region.
               This function requires two images [img,region_label] in the selection.
               Argument 'feature' is a string that corresponds to the way the feature would
               be asked for the entire image.
               Default value: 'default_value=0'.

           -reset:

               Reset global parameters of the interpreter environment.

           -RGB:

               Return a random int-valued RGB color.

           -RGBA:

               Return a random int-valued RGBA color.

           -str:
                               string

               Print  specified  string  into  its  binary,  octal,   decimal   and   hexadecimal
       representations.

           -str2hex:
                               string

               Convert specified string into a sequence of hexadecimal values.

           -stresc:
                               val1,...,valN

               Return escaped string from specified ascii codes.

           -strcat:
                               "string1","string2",...

               Return the concatenation of all strings passed as arguments.

           -strcmp:
                               "string1","string2",_nb_characters>=0

               Return '1' if the two specified strings are equals, '0' otherwise.
               If   'nb_characters'   is   specified,   the  comparison  is  done  only  for  the
       'nb_characters' first
                 characters.

           -strcontains:
                               string1,string2

               Return 1 if the first string contains the second one.

           -strlen:
                               string1

               Return the length of specified string argument.

           -strreplace:
                               string,search,replace

               Search and replace substrings in an input string.

           -strlowercase:
                               string

               Return a lower-case version of the specified string.

           -strvar:
                               string

               Return a simplified version of the  specified  string,  that  can  be  used  as  a
       variable name.

           -strver:
                               _version

               Return the specified version number of the G'MIC interpreter, as a string.
               Default value: 'version=$_version'.

           -tic:

               Initialize tic-toc timer.
               Use it in conjunction with '-toc'.

           -toc:

               Display elapsed time of the tic-toc timer since the last call to '-tic'.
               This command returns the elapsed time in the status value.
               Use it in conjunction with '-tic'.

           -std_noise:

               Return the estimated noise standard deviation of the last selected image.

        ** Other interactive commands:

           -demo:
                               _run_in_parallel={ 0=no | 1=yes | 2=auto }

               Show a menu to select and view all G'MIC interactive demos.

           -x_2048:

               Launch the 2048 game.

           -x_blobs:

               Launch the blobs editor.

           -x_bouncing:

               Launch the bouncing balls demo.

           -x_color_curves:
                               _colorspace={  rgb  |  cmy  | cmyk | hsi | hsl | hsv | lab | lch |
       ycbcr | last }

               Apply color curves on selected RGB[A] images, using an interactive window.
               Set 'colorspace' to 'last' to apply last  defined  color  curves  without  opening
       interactive
                 windows.
               Default value: 'colorspace=rgb'.

           -x_colorize:
                               _is_lineart={    0    |    1   },_max_resolution={   0   |   >=128
       },_multichannels_output={ 0 |
                                 1 },_[palette1],_[palette2],_[grabber1]

               Colorized selected B&W images, using an interactive window.
               When >0, argument 'max_resolution' defines the maximal image  resolution  used  in
       the interactive
                 window.
               Default        values:       'is_lineart=1',       'max_resolution=1024'       and
       'multichannels_output=0'.

           -x_fire:

               Launch the fire effect demo.

           -x_fireworks:

               Launch the fireworks demo.

           -x_fisheye:

               Launch the fish-eye effect demo.

           -x_fourier:

               Launch the fourier filtering demo.

           -x_grab_color:
                               _variable_name

               Open a color grabber widget from the first selected image.
               Argument 'variable_name' specifies the variable that contains the  selected  color
       values at any
                 time.
               Assigning '-1' to it forces the interactive window to close.
               Default values: 'variable_name=xgc_variable'.

           -x_histogram:

               Launch the histogram demo.

           -x_hough:

               Launch the hough transform demo.

           -x_jawbreaker:
                               0<_width<20,0<_height<20,0<_balls<=8

               Launch the Jawbreaker game.

           -x_landscape:

               Launch the virtual landscape demo.

           -x_life:

               Launch the game of life.

           -x_light:

               Launch the light effect demo.

           -x_mandelbrot:
                               _julia={ 0 | 1 },_c0r,_c0i

               Launch Mandelbrot/Julia explorer.

           -x_metaballs3d:

               Launch the 3d metaballs demo.

           -x_minesweeper:
                               8<=_width=<20,8<=_height<=20

               Launch the Minesweeper game.

           -x_minimal_path:

               Launch the minimal path demo.

           -x_pacman:

               Launch pacman game.

           -x_paint:

               Launch the interactive painter.

           -x_plasma:

               Launch the plasma effect demo.

           -x_quantize_rgb:
                               _nbcolors>=2

               Launch the RGB color quantization demo.

           -x_reflection3d:

               Launch the 3d reflection demo.

           -x_rubber3d:

               Launch the 3d rubber object demo.

           -x_segment:
                               _max_resolution={ 0 | >=128 }

               Segment foreground from background in selected opaque RGB images, interactively.
               Return RGBA images with binary alpha-channels.
               Default value: 'max_resolution=1024'.

           -x_select_color:
                               _variable_name

               Display a RGB or RGBA color selector.
               Argument  'variable_name'  specifies the variable that contains the selected color
       values (as R,G,
                 B,[A]) at any time.
               Its value specifies the initial selected color. Assigning '-1' to  it  forces  the
       interactive
                 window to close.
               Default value: 'variable_name=xsc_variable'.

           -x_select_function1d:
                               _variable_name,_background_curve_R,_background_curve_G,_background_curve_B

               Open an interactive window, where the user can defined its own 1d function.
               If an image is selected, it is used to display additional information :
               - The first row defines the values of a background curve displayed on  the  window
       (e.g. an
                 histogram).
               - The 2nd, 3rd and 4th rows define the R,G,B color components displayed beside the
       X and Y axes.
               Argument  'variable_name'  specifies  the  variable  that  contains  the  selected
       function keypoints
                 at any time.
               Assigning '-1' to it forces the interactive window to close.
               Default values: 'variable_name=xsf_variable', 'background_curve_R=220',
                 'background_curve_G=background_curve_B=background_curve_T'.

           -x_select_palette:
                               _variable_name,_number_of_columns={ 0=auto | >0 }

               Open a RGB or RGBA color selector widget from a palette.
               The palette is given as a selected image.
               Argument  'variable_name'  specifies the variable that contains the selected color
       values (as R,G,
                 B,[A]) at any time.
               Assigning '-1' to it forces the interactive window to close.
               Default values: 'variable_name=xsp_variable' and 'number_of_columns=2'.

           -x_shadebobs:

               Launch the shade bobs demo.

           -x_spline:

               Launch spline curve editor.

           -x_tetris:

               Launch tetris game.

           -x_tictactoe:

               Launch tic-tac-toe game.

           -x_waves:

               Launch the image waves demo.

           -x_whirl:
                               _opacity>=0

               Launch the fractal whirls demo.
               Default values: 'opacity=0.2'.

        **** Command shortcuts:

           -h : eq. to '-help'.
           -m  (+): eq. to '-command'.
           -d  (+): eq. to '-display'.
           -d0 : eq. to '-display0'.
           -d3d  (+): eq. to '-display3d'.
           -da : eq. to '-display_array'.
           -dfft : eq. to '-display_fft'.
           -dg : eq. to '-display_graph'.
           -dh : eq. to '-display_histogram'.
           -dp : eq. to '-display_polar'.
           -dq : eq. to '-display_quiver'.
           -drgba : eq. to '-display_rgba'.
           -dt : eq. to '-display_tensors'.
           -dw : eq. to '-display_warp'.
           -e  (+): eq. to '-echo'.
           -i  (+): eq. to '-input'.
           -ig : eq. to '-input_glob'.
           -o  (+): eq. to '-output'.
           -on : eq. to '-outputn'.
           -op : eq. to '-outputp'.
           -ow : eq. to '-outputw'.
           -ox : eq. to '-outputx'.
           -p  (+): eq. to '-print'.
           -sh  (+): eq. to '-shared'.
           -sp : eq. to '-sample'.
           -up : eq. to '-update'.
           -v  (+): eq. to '-verbose'.
           -w  (+): eq. to '-window'.
           -k  (+): eq. to '-keep'.
           -mv  (+): eq. to '-move'.
           -nm  (+): eq. to '-name'.
           -nms : eq. to '-names'.
           -rm  (+): eq. to '-remove'.
           -rv  (+): eq. to '-reverse'.
           -+  (+): eq. to '-add'.
           -&  (+): eq. to '-and'.
           -<<  (+): eq. to '-bsl'.
           ->>  (+): eq. to '-bsr'.
           -/  (+): eq. to '-div'.
           -==  (+): eq. to '-eq'.
           ->=  (+): eq. to '-ge'.
           ->  (+): eq. to '-gt'.
           -<=  (+): eq. to '-le'.
           -<  (+): eq. to '-lt'.
           -//  (+): eq. to '-mdiv'.
           -%  (+): eq. to '-mod'.
           -**  (+): eq. to '-mmul'.
           -*  (+): eq. to '-mul'.
           -!=  (+): eq. to '-neq'.
           -|  (+): eq. to '-or'.
           -^  (+): eq. to '-pow'.
           --  (+): eq. to '-sub'.
           -c  (+): eq. to '-cut'.
           -f  (+): eq. to '-fill'.
           -ir : eq. to '-inrange'.
           -n  (+): eq. to '-normalize'.
           -=  (+): eq. to '-set'.
           -ac : eq. to '-apply_channels'.
           -fc : eq. to '-fill_color'.
           -a  (+): eq. to '-append'.
           -z  (+): eq. to '-crop'.
           -r  (+): eq. to '-resize'.
           -rr2d : eq. to '-resize_ratio2d'.
           -r2dx : eq. to '-resize2dx'.
           -r2dy : eq. to '-resize2dy'.
           -r3dx : eq. to '-resize3dx'.
           -r3dy : eq. to '-resize3dy'.
           -r3dz : eq. to '-resize3dz'.
           -s  (+): eq. to '-split'.
           -y  (+): eq. to '-unroll'.
           -b  (+): eq. to '-blur'.
           -g  (+): eq. to '-gradient'.
           -j  (+): eq. to '-image'.
           -j3d  (+): eq. to '-object3d'.
           -t  (+): eq. to '-text'.
           -to : eq. to '-text_outline'.
           -+3d  (+): eq. to '-add3d'.
           -c3d : eq. to '-center3d'.
           -col3d  (+): eq. to '-color3d'.
           -/3d  (+): eq. to '-div3d'.
           -db3d  (+): eq. to '-double3d'.
           -f3d  (+): eq. to '-focale3d'.
           -l3d  (+): eq. to '-light3d'.
           -m3d  (+): eq. to '-mode3d'.
           -md3d  (+): eq. to '-moded3d'.
           -*3d  (+): eq. to '-mul3d'.
           -n3d : eq. to '-normalize3d'.
           -o3d  (+): eq. to '-opacity3d'.
           -p3d  (+): eq. to '-primitives3d'.
           -rv3d  (+): eq. to '-reverse3d'.
           -r3d  (+): eq. to '-rotate3d'.
           -sl3d  (+): eq. to '-specl3d'.
           -ss3d  (+): eq. to '-specs3d'.
           -s3d  (+): eq. to '-split3d'.
           --3d  (+): eq. to '-sub3d'.
           -t3d  (+): eq. to '-texturize3d'.
           -ap : eq. to '-apply_parallel'.
           -apc : eq. to '-apply_parallel_channels'.
           -apo : eq. to '-apply_parallel_overlap'.
           -endl  (+): eq. to '-endlocal'.
           -x  (+): eq. to '-exec'.
           -l  (+): eq. to '-local'.
           -q  (+): eq. to '-quit'.
           -u  (+): eq. to '-status'.
           -frame : eq. to '-frame_xy'.

          [ Total number of commands: 949 ]

        13. Examples of use
            ---------------

        'gmic' is a generic image processing tool  which  can  be  used  in  a  wide  variety  of
       situations.
        The few examples below illustrate possible uses of this tool:

         - View a list of images:
            gmic file1.bmp file2.jpeg

         - Convert an image file:
            gmic input.bmp -o output.jpg

         - Create a volumetric image from a movie sequence:
            gmic input.mpg -a z -o output.hdr

         - Compute image gradient norm:
            gmic input.bmp -gradient_norm

         - Denoise a color image:
            gmic image.jpg -denoise 30,10 -o denoised.jpg

         - Compose two images using overlay layer blending:
            gmic image1.jpg image2.jpg -blend overlay -o blended.jpg

         - Evaluate a mathematical expression:
            gmic -e "cos(pi/4)^2+sin(pi/4)^2={cos(pi/4)^2+sin(pi/4)^2}"

         - Plot a 2d function:
            gmic 1000,1,1,2 -f "X=3*(x-500)/500;X^2*sin(3*X^2)+if(c==0,u(0,-1),cos(X*10))" -plot

         - Plot a 3d elevated function in random colors:
            gmic 128,128,1,3,"u(0,255)" -plasma 10,3 -blur 4 -sharpen 10000 \
             -elevation3d[-1] "'X=(x-64)/6;Y=(y-64)/6;100*exp(-(X^2+Y^2)/30)*abs(cos(X)*sin(Y))'"

         - Plot the isosurface of a 3d volume:
            gmic -m3d 5 -md3d 5 -db3d 0 -isosurface3d "'x^2+y^2+abs(z)^abs(4*cos(x*y*z*3))'",3

         - Render a G'MIC 3d logo:
            gmic 0 -text G\'MIC,0,0,53,1,1,1,1 -expand_xy 10,0 -blur 1 -n 0,100 --plasma 0.4 -add
       \
             -blur 1 -elevation3d -0.1 -md3d 4

         - Generate a 3d ring of torii:
            gmic -repeat 20 -torus3d 15,2 -color3d[-1] "{u(60,255)},{u(60,255)},{u(60,255)}" \
             -*3d[-1] 0.5,1 -if "{$>%2}" -rotate3d[-1] 0,1,0,90 -endif -add3d[-1] 70 -add3d \
             -rotate3d 0,0,1,18 -done -moded3d 3 -mode3d 5 -db3d 0

         - Create a vase from a 3d isosurface:
            gmic -md3d 4 -isosurface3d "'x^2+2*abs(y/2)*sin(2*y)^2+z^2-3',0" -sphere3d 1.5 \
             -sub3d[-1] 0,5 -plane3d 15,15 -rotate3d[-1] 1,0,0,90 -center3d[-1] -add3d[-1]  0,3.2
       \
             -color3d[-1] 180,150,255 -color3d[-2] 128,255,0 -color3d[-3] 255,128,0 -add3d

         - Display filtered webcam stream:
            gmic -apply_camera \"--mirror x --mirror y -add -div 4\"

         - Launch a set of G'MIC interactive demos:
            gmic -demo

        ** G'MIC comes with ABSOLUTELY NO WARRANTY; for details visit: http://gmic.eu **

                                                                                         G'MIC(1)