I'm new to this list and want to introduce myself with a few words: as
an amateur astronomer I'm interested in operating my CCD camera with
Linux. A few years ago I wrote a little program which was able to
control the camera and read out images, but it had to run suid root.
Having a little bit more time now than in the past years I looked around
for a more compatible solution and found that it must be possible to
control such a camera with SANE. In my oppinion it is really important
for the further development of Linux that not everybody starts his own
project but looks around if he can use existing standards.
The special thing with an astronomical camera is the fact that these
cameras have a temperature controll system and are operated at, let's
say, -20°C. But this should be no problem with that very flexible
options handling defined in the SANE standard.
A few questions:
- Is there more information about how to write a backend? I looked threw
the SANE coding standard V1.0 and found it still difficult to write a
backend myself with what I found there. I played around with the pnm
driver which seems to be a sample implementation, but it is very
poorly
documented and other drivers seem to follow completely different
strategies and style guides. Something like a "How to start writing a
SANE backend" would be nice.
- How do I compile my own backend? At the moment I copied my source into
the sane-1.0/backends directory as root, compiled it there and
installed
the libraries by hand in /usr/local/lib/sane/ (because make install
installs always all libraries found, no matter if they already were
installed). Is this really the right way? Any possibility of making
the source with user permissions and only installing it as root?
- A few samples of how to deal with all these options defined in the
option
descriptor would be nice as well. I tried to setup a string_list, but
if I run xscanimage and select one of the list entries it stops with
xscanimage: can't resolve symbol 'sanei_constrain_value'
- Is there a separation between the API part of the SANE backend and the
hardware dependend routines? Am I simply allowed to access hardware
ports from my backend and are there any guidelines dealing with
compatiblity (what system libraries am I allowed to use) and
portability?
Perhaps most of these topics have been discussed before; in this case a
pointer to the answers would be useful to me.
Thanks a lot in advance,
Robert
-- +---------------------------------------------------------------------+ + Robert Schwebel, Fridtjof-Nansen-Strasse 51, D - 38108 Braunschweig + + Public Observatory Rothwesten (near Kassel, Germany) + + phone: +49-531-353745, e-mail: r.schwebel@tu-bs.de + +---------------------------------------------------------------------+
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