sane-test.5



sane-test(5)             SANE Scanner Access Now Easy             sane-test(5)


NAME

       sane-test - SANE backend for testing frontends


DESCRIPTION

       The sane-test library implements a SANE (Scanner Access Now Easy) back‐
       end 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 explic‐
       itly.  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 back‐
       ends 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)  capa‐
       bilities.  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.   Mini‐
       mum 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  con‐
       straint 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 contain‐
              ing  all the default values is provided together with this back‐
              end.  One  of  the  more  interesting   values   may   be   num
              ber_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/lib64/sane/libsane-test.a
              The static library implementing this backend.

       /usr/lib64/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.  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 config‐
              uration  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 sepa‐
              rator 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


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

                                  14 Jul 2008                     sane-test(5)

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