[sane-devel] gamma-table value

[Henning Meier-Geinitz]

Hi,

On Tue, May 13, 2003 at 02:08:33PM +0100, F J Brooks wrote:
> On advice, I deleted existing SANE-1.0.8-47, XSane-0.87, glib-1.2.9, and
> gtk+-1.2.9 using YaST2.

It's not necessary to delete glib and gtk. In fact, if you do that,
you'll remove all gtk applications from your system and that's
probably not what you want. Removing sane-backends (and maybe xsane as
a dependency) is enough.

Where did you get the impression that glib/gtk must be removed? That
documentation should be fixed.

I guess it would have been even easier to just use a SuSE binary RPM,
e.g. this inofficial one from
http://packman.links2linux.de/index.php4?action=211 (not tested by me).

> I then opened new directory
> /home/<username>/scanner, went to ftp.mostang.com and downloaded into it
> sane-backends-1.0.11, xsane-0.90, glib-2.2.1 and gtk+-2.2.1 (all .tar.gz). I
> then, in turn, unzipped them and gave them the './configure, make, and make
> install' treatment (all in the /home/<username>/scanner directory). In the
> process I had to overcome some problems with 'Error: make:*** No targets
> specified...' etc, and 'Error: make install:*** No rule to make target...'

That usually means that you are not in the directory of the package,
forgot to run configure or configure hasn't finished because of errors.
If this happened in sane-backends, sane-frontends, or xsane, please
tell us the exact error message and what you did before.

> etc, and to download and install 'pkgconfig-0.15.0', and install 'gtk-devel'
> (latter using YaST2)

pkgconfig isn't needed by any SANE package as far as I know. If you
compile gtk from source code, you don't need to install "gtk-devel",
because the headers are included in the source package. In fact, when
you installed gtk-devel you also installed gtk (if you had removed it
at all). So compiling gtk didn't make much sense ...

> I've downloaded/read reams and reams of paper with titles like 'INSTALL',

For installing sane-backends, INSTALL should be enough. For checking
the scanner/scanning: man sane, man scanimage, man sane-avision.

> 'PROBLEMS' and'README' for sane-frontends, backends and xsane, 'Xsane
> Beginners Information', 'sane-avision.5' and 'The SANE Avision backend'.
> I've tried the articles in the April 2003 issue of Linux Journal, and in the
> December 2002 issue of Linux Format. I've downloaded the Yolux tutorial :
> 'Scanners and Linux', and Steve Sheriff's 'Quick & Simple HOWTO...', and
> I've studied the 'Sane FAQ' and 'FAQs about SANE hp-backends', which has a
> question: 'My scanner works with USB on Windows, but not with Linux', which
> seemed to represent my situation, but, having followed through the
> instructions, it was all to no avail. I've consulted several Sane pages from
> the SuSE manual. There is definitely a market niche for good, simple, clear
> documentation that supposes no previous knowledge, and actually matches
> current versions of Linux.

The documentation is in the man pages. If something is missing, it
should be added. Please tell us what didn't work and what's missing.

The problem is: You just can't make a "good, simple, clear
documentation that supposes no previous knowledge". That would be a
big book if it should tell details for every supported scanner.

A short, simple instruction is: Install sane-backends, run scanimage
-L. If it doesn't work, read man sane, man sane-backendname.

But that means that you must know what a shell is, how to start
programs from the shell, how to read man pages. So it doesn't work
without previous knowledge.

> On Sunday, the response to my command $sane-find-scanner was:
> 'found SCSI scanner "HP Scanjet 5300C 6.00" at /dev/scanner
> found SCSI scanner "HP Scanjet 5300C 6.00" at /dev/sg2'

Looks fine.

> The response to $scanimage -L was:
> 'device 'avision:/dev/scanner' is a Hewlett-Packard Scanjet 5300C flatbed
> scanner
> device 'avision:/dev/sg2' is a Hewlett-Packard Scanjet 5300C flatbed
> scanner'

Looks fine, also.

Did you try to actually scan with scanimage? What happened?

> This all looked promising (altho I'm a bit worried as to why there should be
> two items in each case, and wonder if I should delete one!),

If you do a "ls -l /dev/scanner" you'll see that /dev/scanner is just
a link to /dev/sg2. You can remove that link but that's not necessary.

> but, when I try
> to launch scanner [as 'root'] by clicking desktop 'Scanner'
> icon, I get:
> 'KDElnit could not launch "xscanimage": Could not find "xscanimage"
> executable'.

Neither sane-frontends nor sane-backends contains a "desktop Scanner
icon". When you removed sane-backends from your distribution, you most
probably also removed xscanimage (or it was never installed).

> So, yesterday, I downloaded and installed 'sane-frontend-1.0.11'
> (./configure, make, and make install).

Ok. I like xsane more, but your mileage may vary.

> Then, when I clicked the 'Scanner' icon on the desktop, I got a small window
> offering two alternatives:
> 'avision/scanner' and 'avision/sg2'. I tried them both in turn, with the
> same result in each case:
> On 'Acquire Preview', the scanner grunts and whirrs a bit, then I just get a
> black bar across the top of the 'Preview' window. When I click 'Scan', the
> scanner whirrs a bit, then I get error message:
> 'Error: Failed to set value at option gamma-table'.

Maybe the maintainer of the avision backend can answer this part.

The error message looks a bit strange, was this really the exact
wording? Anyway, it probably means that the frontend (xscanimage)
tried to set an option of the backend (avision) and failed. Maybe a
backend problem but I don't remember anyone mentioning it until now.

I know that he has updated the backend to not use that SCSI-over_USB
kernel driver bu that's not in 1.0.11 (but 1.0.12-pre1). I don't know
however, if that has anything to do with your problem.

> I do not understand this at all, and cannot find any trace of it in all the
> literature I've listed above - or any solution on Google.

I guess it's a problem with the backend or the kernel driver. It's not
easy to examine what's going on with so little information. So first
make sure you are really using sane-backends 1.0.11:

scanimage --version

Now try to scan:

scanimage >image.pnm

If that doesn't work, show us the output of:

SANE_DEBUG_AVISION=255 scanimage >image.pnm

> You'll forgive my cynicism if, after all these 'adventures', I give a hollow
> laugh when I note that 'SANE' is an acronym for 'Scanner Access Made Easy'
> [!!!]

It's easy. Well, most of the time :-) I just did "apt-get install
xsane", plugged in my Mustek ScanExpress 1200 CU, started XSane.
Voila, scanning works, took 40 seconds. So basically it works. Your
problems are related to several issues as far as I can see:

a) Not using precompiled packages. Well, I know, SuSE doesn't provide
   updated packages between releases. But that's really not our fault.
b) Misleading documentation (glib/gtk). I hope that's not our docu.
   Otherwise we can fix the docu, but we need specific hints on what's
   wrong or missing.
c) Maybe problems with the backend (or kernel module)?

Bye,
  Henning