sane-test(5) SANE Scanner Access Now Easy sane-test(5)NAMEsane-test - SANE backend for testing frontends
DESCRIPTION
The sane-test library implements a SANE (Scanner Access
Now Easy) backend that allows testing the SANE installa-
tion 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 simu-
lates 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 imple-
ments functions and options that are not (or seldomly)
found in other backends.
The backend is commented out in /usr/free-
ware/etc/sane.d/dll.conf, so either the comment character
must be removed or the backend must be called explicitely.
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 combina-
tion 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 to test whether a fron-
tend 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.
SPECIAL OPTIONS
Option test-picture allows 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 reprented 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-back-
end/test-pictures.html.
If option invert-endianess 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 endianess.
If option read-limit is set, the maximum amount of data
tranferred 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 microsec-
onds the backends waits after each transfer of a buffer.
This option is useful to find timing-related bugs, espe-
cially 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 han-
dling of the SANE statii.
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 num-
bering scheme is inetended for easier detection of options
not displayed by the frontend (bevause 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 auto-
matic (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 con-
straint.
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
/usr/freeware/etc/sane.d/test.conf
The backend configuration file (see also descrip-
tion 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 num-
ber_of_devices. It can be used to check the fron-
tend'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/freeware/lib32/sane/libsane-test.a
The static library implementing this backend.
/usr/freeware/lib32/sane/libsane-test.so
The shared library implementing this backend (pre-
sent 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 /usr/freeware/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 spec-
ified directories. For example, setting SANE_CON-
FIG_DIR to "/tmp/config:" would result in directo-
ries "tmp/config", ".", and "/usr/free-
ware/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 ALSOsane(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
sane-backends 1.0.12 24 Jul 2002 sane-test(5)
