The
sane-hp
library implements a SANE (Scanner Access Now Easy) backend that
provides access to HP ScanJet scanners which support SCL (Scanner
Control Language by HP). The following
scanners are known positively to work with this backend:
Support for models 5200C/62X0C/63X0C connected to the USB require
the kernel scanner driver or libusb. See
sane-usb(5)
for more details.
The "hp" backend no longer supports OfficeJet multi-function peripherals.
For these devices use the external "hpoj" backend in version 0.90 and later of
the "HP OfficeJet Linux driver", available at
http://hpoj.sourceforge.net
Because Hewlett-Packard does no longer produce scanners that support
SCL (beside the OfficeJets), the above list of supported scanners is
complete.
Other HP scanners are not supported by the "hp" backend, but might be supported
by another one. See
http://www.sane-project.org/.
You can also watch the sane-devel mailing list at
http://www.sane-project.org/mailing-lists.html.
Where
special
is the UNIX path-name for the special device that corresponds to the
scanner. For SCSI scanners the special device name must be a generic SCSI
device or a symlink to such a device. Under Linux, such a device name could be
/dev/sga
or
/dev/sg2,
for example. If the special device name contains "usb", "uscanner" or "ugen",
it is assumed that the scanner is connected by USB.
For the HP ScanJet Plus the special device name must be the device
that corresponds to the parallel interface card that was shipped with the
scanner. That is
/dev/hpscan.
A special driver is required for this card.
See ftp://rvs.ctrl-c.liu.se/pub/wingel/hpscan for details. If the link
does not work, try ftp://sunsite.unc.edu/pub/Linux/kernel/patches/scanners.
CONFIGURATION
The contents of the
hp.conf
file is a list of options and device names that correspond to HP ScanJet
scanners. Empty lines and lines starting with a hash mark
(#) are ignored. See
sane-scsi(5)
and
sane-usb(5)
on details of what constitutes a valid device name.
Options specified in front of the first line that contains a device name
are defaults for all devices. Options specified below a line that
contains a device name apply just to the most recently mentioned device.
Supported options are
connect-scsi,
connect-device,
enable-image-buffering,
and
dumb-read.
Option
connect-scsi
specifies that the scanner is connected to the system by SCSI.
Input/output is performed using SCSI-commands. This is the default.
But if your SCSI device name contains "usb", "uscanner" or "ugen",
option connect-scsi must be specified. Otherwise it is assumed that
the scanner is connected by USB.
Option
connect-device
specifies that the scanner is connected to the system by a special
device. Input/output is performed by read()/write()-operations
on the device. This option must be used for HP ScanJet Plus
or scanners connected to USB which are accessed through a named device
(e.g. /dev/usb/scanner0).
For device names that contain "usb", "uscanner" or "ugen", it is not
necessary to specify option connect-device.
Option
enable-image-buffering
stores the scanned image in memory before passing it to the frontend. Could be
used in case of forward/backward moving scanner lamp.
Option
dumb-read
can be used to work around problems with "Error during device I/O". These
problems may occur with certain SCSI-to-USB converters or Buslogic SCSI cards.
The option should not be used for SCSI devices which are working correctly.
Otherwise startup of frontends and changing parameters might be slower.
A sample configuration file is shown below:
/dev/scanner
# this is a comment
/dev/hpscan
option connect-device
/dev/scanner is typically a symlink to the actual SCSI scanner device.
FILES
/etc/sane.d/hp.conf
The backend configuration file (see also description of
SANE_CONFIG_DIR
below).
/usr/lib/sane/libsane-hp.a
The static library implementing this backend.
/usr/lib/sane/libsane-hp.so
The shared library implementing this backend (present on systems that
support dynamic loading).
$HOME/.sane/calib-hp:<device>.dat
Calibration data for HP PhotoSmart PhotoScanner that is retrieved from the
scanner after calibration. The data is uploaded to the scanner at start
of the backend if it is in media mode 'print media' or if the media mode is
changed to 'print media'.
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 /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_HP
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_HOME_HP
Only used for OS/2 and along with use of HP PhotoSmart PhotoScanner.
Must be set to the directory where the directory .sane is located.
Is used to save and read the calibration file.
SANE_HP_KEEPOPEN_SCSI
SANE_HP_KEEPOPEN_USB
SANE_HP_KEEPOPEN_DEVICE
For each type of connection (connect-scsi, connect-usb, connect-device)
it can be specified if the connection to the device should be kept open ("1")
or not ("0").
Usually the connections are closed after an operation is performed.
Keeping connection open to SCSI-devices can result in errors during device IO
when the scanner has not been used for some time. By default, USB-connections
are kept open. Other connections are closed.
SANE_HP_RDREDO
Specifies number of retries for read operation before returning an EOF error.
Only supported for non-SCSI devices. Default: 1 retry. Time between retries
is 0.1 seconds.
BUGS
HP PhotoSmart PhotoScanner
In media mode 'slide' and 'negative', scan resolutions are rounded to
multiple of 300 dpi. The scanner does not scale the data correctly
on other resolutions. Some newer models (firmware code R030 and later)
do not support adjustment of contrast/intensity level and tone map.
The backend will simulate this by software, but only for gray
and 24 bit color.
Automatic Document Feeder (ADF)
For use of the ADF with xscanimage(1), first place paper in the ADF and
then change option scan source to 'ADF'. Press 'change document'
to load a sheet. Then press 'scan' to start a scan.
Maybe it is sufficient to press 'scan' without 'change document'
for repeated scans. The use of the preview window is not recommended
when working with the ADF.
Setting a window to scan from ADF is not supported with xscanimage(1).
Try xsane(1).
Immediate actions
Some actions in xscanimage(1) (i.e. unload, select media, calibrate)
have an immediate effect on the scanner without starting a scan.
These options can not be used with scanimage.
TODO
HP PhotoSmart PhotoScanner
PhotoScanners with firmware release R030 and up have
no firmware support for contrast/brightness/gamma table. In the current
backend this is simulated by software on 24 bits data.
Simulation on 30 bits should give better results.
Data widths greater than 8 bits
Custom gamma table does not work.
Parallel scanner support
Beside the ScanJet Plus which came with its own parallel interface card,
currently only the HP ScanJet 5100C/5200C are supported.
These scanners are using an internal parallel-to-SCSI converter which
is supported by the ppSCSI-driver (see above).
