sane-project-backends/doc/sane-canon_pp.man

.TH sane-canon_pp 5 "7 April 2002"
.IX sane-canon_pp
.SH NAME
sane-canon_pp - SANE backend for Canon Parallel Port flatbed scanners
.SH DESCRIPTION
The
.B sane-canon_pp
library implements a SANE (Scanner Access Now Easy) backend that
provides access to the following Canon flatbed scanners:
.PP
.RS
CanoScan FB330P
.br
CanoScan FB630P
.br
CanoScan N340P
.br
CanoScan N640P
.br
CanoScan N640P ex
.br
.RE
.PP
No USB scanners are supported and there are no plans to support them in 
the future.  Other projects are working on support for USB scanners. See the 
.B PROJECTS 
file for more detail.  We cannot add support for the FB310P or FB320P at the
moment, but contact us if you have one of these scanners and would really like
to help.
.PP
IMPORTANT: this is alpha code. While we have made every effort to make it as
reliable as possible, it will not always work as expected.  Feedback is still
appreciated.  Please send any bug reports to the maintainers as listed on the
web page (listed in
.B SEE ALSO
below).
.PP
.
.PP
.SH "DEVICE NAMES"
This backend expects device names of the form presented by libieee1284.  These names are highly dependant on operating system and version.

On Linux 2.4 kernels this will be of the form 
.I "parport0"
or older (2.2) kernels may produce names like 
.IR "0x378"
or simply 
.IR "0"
depending on your module configuration.  Check the contents of 
.I /proc/parport
if it exists.  If you don't want to specify a default port (or don't know 
its name), the backend should be able to detect which port your scanner is on.

.SH CONFIGURATION
The contents of the
.I canon_pp.conf
file is a list of options for the driver to use.  Empty lines and lines 
starting with a hash mark (#) are ignored.
.PP
The supported options are currently
.BR ieee1284 ,
.BR calibrate ,
and 
.BR force_nibble

Option
.B ieee1284 
.IR portname
defines which port to use.  The format of portname is OS dependant, based on 
the names presented by libieee1284.  Please only have one of these lines, or
all but one will be ignored.

Option 
.B calibrate 
.IR cal-file 
.IR [portname]
defines which calibration file to use on a per-port basis.  If you only have 
one scanner, the portname argument may be omitted - but be careful as this 
will cause problems on multi-scanner systems.  You may have as many of these
lines as you like, as long as each has a unique port name.  The tilde (`~') 
character is acceptable and will be expaned to the value of the HOME environment.

Option
.B force_nibble
forces the driver to use nibble mode even if ECP mode is reported to work
by libieee1284.  This works-around the rare issue of ECP mode being reported to
work by the library, then not working.

.SH TIPS
.PP
Hit the "Calibrate" button before scanning.  It vastly improves the quality
of scans.
.PP
To enable automatic detection of your scanner, uncomment the "canon_pp" line from
.I @CONFIGDIR@/dll.conf
.PP
.SH FILES
.TP
.I @CONFIGDIR@/canon_pp.conf
The backend configuration file (see also description of
.B SANE_CONFIG_DIR
below).
.TP
.I @LIBDIR@/libsane-canon_pp.a
The static library implementing this backend.
.TP
.I @LIBDIR@/libsane-canon_pp.so
The shared library implementing this backend (present on systems that
support dynamic loading).
.SH ENVIRONMENT
.TP
.B 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
.B SANE_CONFIG_DIR
to "/tmp/config:" would result in directories "tmp/config", ".", and
"@CONFIGDIR@" being searched (in this order).
.TP
.B SANE_DEBUG_CANON_PP
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_CANON_PP=4
.SH NOTES
.B Features available in the Windows interface
.TP
.B Brightness and Contrast 
These are not implemented, and probably never will be.  These
appear to be implented entirely in software.  Use GIMP or a similar program if
you need these features.
.TP
.B Descreen Mode
This appears on our first analysis to be just oversampling with an 
anti-aliasing filter.  Again, it seems to be implemeneted entirely in 
software, so GIMP is your best bet for now.
.TP
.B Gamma Tables
This is under investigation, but for now only a simple gamma profile will be 
loaded.
.PP
.B Other Notes
.PP
ECP mode in libieee1284 doesn't always work properly, even with new hardware.  
We beleive that this is a ppdev problem.  If you change the configuration file
to include 
.B force_nibble
, the problem will go away, but you will only be able to scan in nibble mode.
.PP
Sometimes the scanner can be left in a state where our code cannot revive it.
If the backend reports no scanner present, try unplugging the power and 
plugging it back in.  Also try unplugging printers from the passthrough port.
.PP
The scanner will not respond correctly to our commands when you first plug in 
the power.  You may find if you try a scan very soon after plugging in the 
power that the backend will incorrectly report that you have no scanner present.
To avoid this, give it about 10 seconds to reset itself before attempting any 
scans.

.SH "SEE ALSO"
sane(7), sane-dll(5)
.BR
http://canon-fb330p.sourceforge.net/

.SH AUTHOR
This backend is primarily the work of Simon Krix (Reverse Engineering), and 
Matthew Duggan (SANE interface).  
.PP
Many thanks to Kevin Easton for his comments and help, and Kent A. Signorini 
for his help with the N340P.