sane-pint - SANE backend for scanners that use the PINT device driver
The sane-pint library implements a SANE (Scanner Access Now Easy) backend
that provides generic access to hand-held and flatbed scanners
using the PINT (PINT Is Not Twain) device driver. The PINT driver is
being actively developed on the OpenBSD platform, and has been ported
to a few other *nix-like operating systems.
PINT is designed to provide an ioctl(2) interface to many different
scanner types. However, this backend has only been tested with flatbed
single-pass scanners, and more work will probably be required to get it
to use other scanner types successfully.
If have successfully used the PINT driver with your scanner, but it
does not work using this SANE backend, please let us know. To do this,
send a mail with the relevant information for your scanner to
[email protected]. Have a look at
http://www.mostang.com/sane/mail.html concerning subscription to sanedevel.
This backend expects device names of the form:
special
Where special is the UNIX path-name for the special device that corresponds
to the scanner. The special device name must be a PINT device
or a symlink to such a device. For example, under NetBSD or OpenBSD,
such a device name could be /dev/ss0 or /dev/scan0.
The contents of the pint.conf. file is a list of device names that
correspond to PINT scanners. Empty lines and lines starting with a
hash mark (#) are ignored. A sample configuration file is shown below:
/dev/scanner
# this is a comment
/dev/ss1
/etc/sane.d/pint.conf
The backend configuration file (see also description of
SANE_CONFIG_DIR below).
/usr/lib/sane/libsane-pint.a
The static library implementing this backend.
/usr/lib/sane/libsane-pint.so
The shared library implementing this backend (present on systems
that support dynamic loading).
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 /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_PINT [Toc] [Back]
If the library was compiled with debug support enabled, this
environment variable controls the debug level for this backend.
E.g., a value of 128 requests all debug output to be printed.
Smaller levels reduce verbosity.
sane(7)
Gordon Matzigkeit, adapted from existing backends written by David Mosberger.
There are minor roundoff errors when adjusting the ranges, since PINT
uses units of 1/1200 of an inch, and SANE normally uses millimeters.
Symptoms of these errors are skewed images. This should really be
fixed (no pun intended) as soon as possible, but I just don't know/care
enough about fixed-point representation and roundoff errors to do this
correctly. Workaround: use inches as the scanning unit, and everything
usually works fine.
The PINT 0.5e interface does not provide a way to determine valid
ranges for DPI, modes, and scan sizes. So, the SANE backend queries
the PINT device, and dynamically discovers valid ranges by doing a
binary search. This means that the driver takes longer to initialize
than seems necessary.
Resetting the scanner does not seem to work (at least not on my HP
ScanJet 4p). For that reason, the driver sends a SCIOCRESTART, then
gobbles up any remaining input until it hits EOF.
Not all of the scanners have been identified (i.e. whether they are
flatbed or handheld).
X and Y resolutions are assumed to be the same.
No testing has been done on three-pass or handheld scanners, or with
Automatic Document Feeder support.
13 May 1998 sane-pint(5)
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