sane-apple - SANE backend for Apple flatbed scanners

The sane-apple library implements a SANE (Scanner Access Now Easy) backend that provides access to Apple flatbed scanners. At present, the following scanners are supported from this backend:

--------------- ----- ------------------ ------
AppleScanner    4bit  16 Shades of Gray
OneScanner      8bit  256 Shades of Gray
ColorOneScanner 24bit RGB color          3-pass

If you own a Apple scanner other than the ones listed above that works with this backend, please let us know by sending the scanner's model name, SCSI id, and firmware revision to sane-devel@lists.alioth.debian.org. See http://www.sane-project.org/mailing-lists.html for details on how to subscribe to sane-devel.

This backend expects device names of the form:

special

Where special is either the path-name for the special device that corresponds to a SCSI 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/sge, for example. See sane-scsi(5) for details.

The contents of the apple.conf file is a list of options and device names that correspond to Apple scanners. Empty lines and lines starting with a hash mark (#) are ignored. See sane-scsi(5) on details of what constitutes a valid device name.

Options come in two flavors: global and positional ones. Global options apply to all devices managed by the backend whereas positional options apply just to the most recently mentioned device. Note that this means that the order in which the options appear matters!

SCSI scanners are typically delivered with an ISA SCSI adapter. Unfortunately, that adapter is not worth much since it is not interrupt driven. It is (sometimes) possible to get the supplied card to work, but without interrupt line, scanning will put so much load on the system, that it becomes almost unusable for other tasks.

/etc/sane.d/apple.conf

The backend configuration file (see also description of SANE_CONFIG_DIR below).

/usr/lib/sane/libsane-apple.a

The static library implementing this backend.

/usr/lib/sane/libsane-apple.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_APPLE

If the library was compiled with debug support enabled, this environment variable controls the debug level for this backend. E.g., a value of 255 requests all debug output to be printed. Smaller levels reduce verbosity.

The apple backend is now in version 0.3 (Tue Jul 21 1998). Since I only have the AppleScanner and not the other models (OneScanner, ColorOneScanner) I can only develop/test for the AppleScanner effectively. However with this release I almost complete the gui part of all scanners. Most of the functionality is there. At least OneScanner should scan at the AppleScanner's compatible modes (LineArt, HalfTone, Gray16). My personal belief is that with a slight touch of debugging the OneScanner could be actually usable. The ColorOneScanner needs more work. AppleScanner is of course almost fully supported.

Currently all 3 models are lacking upload/dowload support.

AppleScanner

Cannot up/download a halftone pattern.

OneScanner

Cannot up/download halftone pattern and calibration vector.

ColorOneScanner

Cannot up/download halftone pattern, calibration vectors, custom Color Correction Table (CCT) and of course custom gamma tables.

Park/UnPark (OneScanner, ColorOneScanner)

The above functionalities are not only missing because I don't actually have the hardware to experiment on it. Another reason is the lack of understanding of how SANE API could provide enaugh means to me to actually describe other array types than the gamma one.

The following "features" will never be supported. At least as I am maintaining the sane-apple backend.

NoHome (AppleScanner)

The scanner lamp stays on and the carriage assembly remains where it stops at the end of the scan. After two minutes, if the scanner does not receive another SCAN command the lamp goes off and the carriage returns to the home position.

Compression (AppleScanner)

The Scanner can compress data with CCITT Group III, one dimensional algorithm (fax), and the Skip White Line algorithm.

Multiple Windows (AppleScanner)

AppleScanner may support multiple windows. It would be a cool feature and a challenge for me to code it if you could intermix different options for different windows (scan areas). This way you could scan a document in LineArt mode but the figures in it on Gray and in a different resolution. Unfortunately this is impossible.

Scan Direction (OneScanner)

It controls the scan direction. (?)

Status/Reset Button (OneScanner)

This option controls the status of the button in OneScanner model. You can also reset the button status by software.

The bugs in a sane backend are divided in two classes. We have GUI bugs and scanner specific bugs.

We know we have a GUI bug when a parameter is not showing up itself when it should (active) or vice versa. To find out which parameters are active accross various Apple modes and models from the documentation ftp://ftpdev.info.apple.com/devworld/Technical_Documentation/Peripherals_Documentation/ is an interesting exercise. I may missed some dependancies. For example for the threshold parameter the Apple Scanners Programming guide says nothing. I had to assume that is valid only in LineArt mode.

Scanner specific bugs are mostly due to mandatory round offs in order to scan. In the documentation in some place states that the width of the scan area should be a byte multiple. In an other place says that the width of the scan area should be an even byte multiple. Go figure...

Other source of bugs are due to scsi communcation, scsi connects and disconnects. However the classical bugs are still there. So you may encouter buffer overruns, null pointers, memory corruption and SANE API violations.

SIGSEGV on SliceBars

When you try to modify the scan area from the slice bar you have a nice little cute core dump. I don't know why. If you select the scan are from the preview window, or by hand typing the numbers everything is fine. The SIGSEGV happens deep in gtk library (gdk). I really cannot debug it.

Options too much

It is possible, especially for the ColorOneScanner, that the backend's options panel to exceed from your screen. It happens with mine and I am running at 1024x768 my X Server. What can I say? Try smaller fonts in the X server, or virtual screens.

Weird SCSI behaviour

I am quoting David Myers Here...

>> OS: FreeBSD 2.2.6

>> CC: egcs-1.02

Just wanted to follow up on this... I recently changed my SCSI card from the Adaptec 2940UW to a dual-channel Symbios 786 chipset. When I started up SANE with your driver, I managed to scan line art drawings okay, but Gray16 scans led to a stream of SCSI error messages on the console, ultimately hanging with a message saying the scanner wasn't releasing the SCSI bus. This may be that the Symbios is simply less tolerant of ancient hardware, or may be bugs in your driver or in SANE itself...

If you encounter a GUI bug please set the environment variable SANE_DEBUG_APPLE to 255 and rerun the excact sequence of keystrokes and menu selections to reproduce it. Then send me a report with the log attached.

It would be very helpfull if you have handy an Apple machine (I am not sure how Mackintoshs are spelled) with the AppleScanners driver installed and check what option are grayed out (inactive) in what modes and report back to me.

If you want to offer some help but you don't have a scanner or you don't have the model you would like to offer some help, or you are a sane developer and you just want to take a look at how the apple backend looks like. Goto to apple.h and #define the NEUTRALIZE_BACKEND macro. You can select the scanner model through the APPLE_MODEL_SELECT macro. Available options are APPLESCANNER, ONESCANNER, COLORONESCANNER.

If you encounter a SCSI bus error or trimmed and/or displaced images please also set the environment variable SANE_DEBUG_SANEI_SCSI to 255 before sendme the report.

Non Blocking Support

Make sane-apple a non blocking backend. Properly support for sane_set_io_mode and sane_get_select_fd

Scan

Make scan possible for all models in all supported modes.

Missing Functionality

sane(7), sane-scsi(5)

The sane-apple backend was written not entirely from scratch by Milon Firikis. It is mostly based on the mustek backend from David Mosberger and Andreas Czechanowski