[sane-devel] test backend: 1 bit RGB data for grid pattern

abel deuring a.deuring@satzbau-gmbh.de
Tue, 24 Sep 2002 23:58:41 +0200


Hi all,

while playing with the test backend, I noticed that the "scan data" 
produced for the grid pattern in 1 bit RGB mode differs from the output 
for 1 bit grayscale mode. The data for gray scale mode is like:

	... 00 00 00 0f ff ff ff f0 00 00 00 ...

while the data for 1 bit RGB mode is:

	... 00 00 00 f0 ff ff ff 0f 00 00 00 ...

(where one number in the line above means actually "means" three bytes 
for the three colors.)

I'm too tired to check the Sane API doc, instead a question: Am I right 
that this is a bug, or do we have different bit orders for 1 bit gray 
and RGB mode ?

I don't think so; the fix would be to change line 173 in test-picture.c 
from:

	SANE_Word xfull = x * 8 / 3 + x1;

to:

	SANE_Word xfull = x * 8 / 3 + (7 - x1);


Abel