[sane-devel] Film holder control (and adf)

[Jose Paulo Moitinho de Almeida]

Hello

I have been looking at the "best way" to control film holder movement. As far 
as I could tell in 1.0.6 no backend was supporting this (at least  the 
coolscan and the canon fs didn't).

Today I had a look at the coolscan2 project. It allows an option -frame as in:

scanimage -frame 3

My proposal is similar, but more elaborate. I think that it could also be 
arranged so that it facilitates life for adf scanners. Possible commands 
would be:

scanimage -number-of-frames
                prints 1 for normal flatbeds, 
                4 or 6 for film holders
                the number of frames in the aps cassette
                0 or -1 if there is an adf feeder
scanimage -can-move-back
	a scanner property, probably false for adf scanners
scanimage -which-frame
scanimage -goto-next-frame
	fails if the last frame in the film strip or in the adf cassete 
	has been reached or if there are no more sheets in the adf
scanimage -goto-previous-frame
	fails if already at the beginning
scanimage -goto-frame 3

This interface and an extension in the api would allow a simple integration 
with other frontends.

Comments?

Regards

Ze Paulo