Ubuntu Manpage: sane-test - SANE backend for testing frontends

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 /etc/sane.d/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 (red/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 7 int test options in total.

       Option int (1/7) is an int test option with no unit and no constraint set.

       Option int-constraint-range (2/7) 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 (3/7) is an int test option with unit bits and constraint
       word list set.

       Option int-constraint-array (4/7) is an int test option with unit mm and  using  an  array
       without constraints.

       Option  int-constraint-array-constraint-range (5/7) 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 (6/7) is an int  test  option  with  unit
       percent and using an array a word list constraint.

       Option  int-inexact  (7/7)  is  an int test option that increments the requested value and
       returns flag SANE_INFO_INEXACT.

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

       /etc/sane.d/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.

       /usr/lib/x86_64-linux-gnu/sane/libsane-test.a
              The static library implementing this backend.

       /usr/lib/x86_64-linux-gnu/sane/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.  On *NIX systems, 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 /etc/sane.d.  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 /etc/sane.d 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

AUTHOR

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

BUGS

       - config file values aren't tested for correctness

                                           14 Jul 2008                               sane-test(5)