[sane-devel] question about SANE backend fill_buffer function

[Nicolas Martin]

Le mardi 07 septembre 2010 à 19:47 +0900, Gernot Hassenpflug a écrit :
> Dear all,
> 
> I am working on the pixma backend for Canon devices (variation:
> pixma_mp150.c), and have a question about registration of pixels in
> the y dimension.
> 
> Each backend I believe has variations on a <filename>_fill_buffer
> function called between <file>_scan and <>_finish_scan.
> 
> The function reads sections of data from the scanner, and processes it
> line by line. Thus, pixels can be reorganized in the x-dimension.
> 
> I am not sure if the amount of data read at once is controllable.
> 
> I now have a problem where the pixels also need to be rearranged
> vertically. In particular, the first half of a line corresponds to the
> second half of a line much further along in the data.
> 
> Is there any backend that has support for such processing, that I can
> look at for help? Or have I misunderstood what can be done with the
> current mp150_fill_buffer function in pixma_mp150.c?
> 
Yes, as I answered you, the pixma_mp150 implements a vertical shift
reassembling that is needed by the CCD devices, as they produce scans
with vertically shifted color planes. Maybe you can just use this, or
use some modified version.

Nicolas