Provided by: libsane-common_1.0.27-3.2ubuntu3_all bug

NAME

       sane-test - SANE backend for testing frontends

DESCRIPTION

       The  sane-test  library  implements  a  SANE (Scanner Access Now Easy) backend that allows
       testing the SANE installation and SANE  frontends.   It  provides  access  to  a  (nearly)
       unlimited  number  of  virtual devices.  There is no support for real scanners or cameras.
       However, the backend simulates scanning and setting options.

       The idea is not only to find bugs in frontends but also to show all capabilities of  SANE.
       Therefore  sane-test  implements  functions  and options that are not (or seldom) found in
       other backends.

       The backend is commented out in @CONFIGDIR@/dll.conf, so either the comment character must
       be  removed  or  the  backend  must  be  called  explicitly.  E.g.  `scanimage -d test' or
       `xscanimage test'.

SCAN MODE OPTIONS

       Option mode selects the scan mode (Gray or Color).

       Option depth determines the number of bits per sample (1. 8, or 16).  Keep in  mind,  that
       this  value refers to the sample, not the pixel.  So depth=16 results in 48 bits per pixel
       in color mode. The most usual combinations are mode=Gray, depth=1 for lineart,  mode=Gray,
       depth=8  for  gray  and  mode=Color, depth=8 for color mode.  The combination of color and
       1-bit mode is quite obscure (8 colors) but allowed in  the  SANE  standard.  However,  the
       meaning  of  bits  is  not  defined. Currently 1 = high intensity and 0 = low intensity is
       used.

       Setting option hand-scanner results in the  test-backend  behaving  like  a  hand-scanner.
       Hand-scanners do not know the image height a priori.  Instead, they return a height of -1.
       Setting this option allows one to test whether a frontend can handle this correctly.  This
       option also enables a fixed width of 11 cm.

       Setting  option three-pass simulates a three-pass scanner.  Older color scanners needed to
       scan the image once per color (reg/green/blue) to get the full image.  Therefore, in  this
       mode three single frames are transmitted in color mode.

       Option  three-pass-order  provides support for changing the order of the three frames (see
       option three-pass above).  A frontend should support all orders.

       Option resolution sets the resolution of the image in dots per inch.

       Option source can be used to simulate an Automatic Document Feeder (ADF). After 10  scans,
       the ADF will be "empty".

SPECIAL OPTIONS

       Option  test-picture  allows  one to set the image that's returned to the frontend.  While
       "Solid white" and "Solid black" are quite  obvious,  the  other  options  need  some  more
       explanation.   Color  patterns  are  used  to  determine if all modes and their colors are
       represented correctly by the frontend.  The grid should look like the same in  every  mode
       and   resolution.    A   table   of   all   the   test   pictures   can   be   found   at:
       http://www.meier-geinitz.de/sane/test-backend/test-pictures.html.

       If option invert-endianness is set, the upper and lower bytes of  image  data  in  16  bit
       modes  are exchanged.  This option can be used to test the 16 bit modes of frontends, e.g.
       if the frontend uses the correct endianness.

       If option read-limit is set, the maximum amount of data  transferred  with  each  call  to
       sane_read() is limited.

       Option  read-limit-size  sets  the  limit  for  option read-limit.  A low limit slows down
       scanning.  It can be used to detect  errors  in  frontend  that  occur  because  of  wrong
       assumptions on the size of the buffer or timing problems.

       Option read-delay enables delaying data to the frontend.

       Option  read-delay-duration  selects  the  number of microseconds the backends waits after
       each transfer of a buffer.  This option is useful to find timing-related bugs,  especially
       if used over the network.

       If  option  read-return-value  is  different  from  "Default", the selected status will be
       returned by every call to sane_read().  This is useful to test the frontend's handling  of
       the SANE statuses.

       If option ppl-loss is different from 0, it determines the number of pixels that are "lost"
       at the end of each line.  That means, lines are padded with unused data.

       Option fuzzy-parameters selects that fuzzy (inexact) parameters are returned  as  long  as
       the  scan  hasn't  been started.  This option can be used to test if the frontend uses the
       parameters it got before the start of the scan (which it shouldn't).

       Option non-blocking determines if non-blocking  IO  for  sane_read()  should  be  used  if
       supported by the frontend.

       If  option  select-fd  is set, the backend offers a select filedescriptor for detecting if
       sane_read() will return data.

       If option enable-test-options is set, a fairly big list of options for testing the various
       SANE option types is enabled.

       Option print-options can be used to print a list of all options to standard error.

GEOMETRY OPTIONS

       Option tl-x determines the top-left x position of the scan area.

       Option tl-y determines the top-left y position of the scan area.

       Option br-x determines the bottom-right x position of the scan area.

       Option br-y determines the bottom-right y position of the scan area.

BOOL TEST OPTIONS

       There  are  6  bool test options in total.  Each option is numbered.  (3/6) means: this is
       option 3 of 6.  The numbering scheme is intended  for  easier  detection  of  options  not
       displayed by the frontend (because of missing support or bugs).

       Option  bool-soft-select-soft-detect  (1/6) is a bool test option that has soft select and
       soft detect (and advanced) capabilities.  That's just a normal bool option.

       Option bool-hard-select-soft-detect (2/6) is a bool test option that has hard  select  and
       soft  detect  (and  advanced)  capabilities.   That  means  the option can't be set by the
       frontend but by the user (e.g. by pressing a button at the device).

       Option bool-hard-select (3/6) is a bool test option that has hard  select  (and  advanced)
       capabilities.  That means the option can't be set by the frontend but by the user (e.g. by
       pressing a button at the device) and can't be read by the frontend.

       Option bool-soft-detect (4/6) is a bool test option that has soft  detect  (and  advanced)
       capabilities.  That means the option is read-only.

       Option  bool-soft-select-soft-detect-emulated  (5/6)  is  a Bool test option that has soft
       select, soft detect, and emulated (and advanced) capabilities.

       Option bool-soft-select-soft-detect-auto (6/6) is a Bool test option that has soft select,
       soft  detect, and automatic (and advanced) capabilities.  This option can be automatically
       set by the backend.

INT TEST OPTIONS

       There are 6 int test options in total.

       Option int (1/6) is an int test option with no unit and no constraint set.

       Option int-constraint-range (2/6) is an int test option with  unit  pixel  and  constraint
       range set.  Minimum is 4, maximum 192, and quant is 2.

       Option  int-constraint-word-list (3/6) is an int test option with unit bits and constraint
       word list set.

       Option int-constraint-array (4/6) is an int test option with unit mm and  using  an  array
       without constraints.

       Option  int-constraint-array-constraint-range (5/6) is an int test option with unit mm and
       using an array with a range constraint.  Minimum is 4, maximum 192, and quant is 2.

       Option int-constraint-array-constraint-word-list (6/6) is an int  test  option  with  unit
       percent and using an array a word list constraint.

FIXED TEST OPTIONS

       There are 3 fixed test options in total.

       Option fixed (1/3) is a fixed test option with no unit and no constraint set.

       Option  fixed-constraint-range  (2/3)  is  a  fixed  test option with unit microsecond and
       constraint range set. Minimum is -42.17, maximum 32767.9999, and quant is 2.0.

       Option fixed-constraint-word-list (3/3) is a Fixed test option with no unit and constraint
       word list set.

STRING TEST OPTIONS

       There are 3 string test options in total.

       Option string (1/3) is a string test option without constraint.

       Option  string-constraint-string-list  (2/3)  is  a  string  test  option with string list
       constraint.

       Option string-constraint-long-string-list (3/3) is a string test option with  string  list
       constraint. Contains some more entries...

BUTTON TEST OPTION

       Option button (1/1) is a Button test option. Prints some text...

FILES

       @CONFIGDIR@/test.conf
              The backend configuration file (see also description of SANE_CONFIG_DIR below). The
              initial values of most of the basic SANE options can be configured in this file.  A
              template  containing all the default values is provided together with this backend.
              One of the more interesting values may be number_of_devices.  It  can  be  used  to
              check  the  frontend's  ability  to show a long list of devices.  The config values
              concerning resolution and geometry can be useful to test the handling of  big  file
              sizes.

       @LIBDIR@/libsane-test.a
              The static library implementing this backend.

       @LIBDIR@/libsane-test.so
              The  shared  library  implementing  this  backend  (present on systems that support
              dynamic loading).

ENVIRONMENT

       SANE_CONFIG_DIR
              This environment variable specifies the list of directories that  may  contain  the
              configuration  file.   Under  UNIX, the directories are separated by a colon (`:'),
              under OS/2, they are separated by a semi-colon (`;').  If this variable is not set,
              the  configuration  file is searched in two default directories: first, the current
              working directory (".") and then in @CONFIGDIR@.  If the value of  the  environment
              variable  ends with the directory separator character, then the default directories
              are searched after the explicitly  specified  directories.   For  example,  setting
              SANE_CONFIG_DIR  to  "/tmp/config:"  would result in directories "tmp/config", ".",
              and "@CONFIGDIR@" being searched (in this order).

       SANE_DEBUG_TEST
              If the library was compiled with debug support enabled, this  environment  variable
              controls  the  debug  level  for  this  backend.   Higher debug levels increase the
              verbosity of the output.

              Example: export SANE_DEBUG_TEST=4

SEE ALSO

       sane(7), http://www.meier-geinitz.de/sane/test-backend/

AUTHOR

       Henning Meier-Geinitz <henning@meier-geinitz.de>

BUGS

       - config file values aren't tested for correctness

@PACKAGEVERSION@                           14 Jul 2008                               sane-test(5)