Hi,
On Fri, Jan 24, 2003 at 03:56:18AM +0100, Andrea Suatoni wrote:
> 3) I've tried to fix the xcam code related to the GdkImage data buffer
> filling. I've resorted to the RGB shift values contained in the GdkVisual
> associated to the image.
Good idea.
> It seems to work pretty well now, and should be more
> portable among different platforms and X11 visuals. The code should be tested
> on little endian architectures, and with 15 or 16 bits visuals.
24 bit/ 4 bytes per pixel work (on little endian). I can't test the
other 24/32 bit modes. I've applied this part of the patch.
15/16 bit doesn't work:
> case 16: \
> - rgb = ( (((r) >> 11) << 11) /* 5 bits of red */ \
> - | (((g) >> 10) << 5) /* 6 bits of green */ \
> - | (((b) >> 11) << 0)); /* 5 bits of blue */ \
> + rgb = ( (((r) >> 8) << r_shift)
> \
> + | (((g) >> 8) << g_shift) \
> + | (((b) >> 8) << b_shift)); \
You can't just >> 8, because only 5/6 bits are significant. So the
shift must be 11/10 as above. The following patch works, however. At
least here on little endian in 15/16 bit modes.
Index: xcam.c
===================================================================
RCS file: /cvsroot/external/sane/sane-frontends/src/xcam.c,v
retrieving revision 1.5
retrieving revision 1.6
diff -u -u -r1.5 -r1.6
--- xcam.c 24 Jan 2003 14:58:11 -0000 1.5
+++ xcam.c 24 Jan 2003 15:08:26 -0000 1.6
@@ -653,17 +653,17 @@
break; \
\
case 15: \
- rgb = ( (((r) >> 11) << 10) /* 5 bits of red */ \
- | (((g) >> 11) << 5) /* 5 bits of green */ \
- | (((b) >> 11) << 0)); /* 5 bits of blue */ \
+ rgb = ( (((r) >> 11) << r_shift) /* 5 bits of red */
\
+ | (((g) >> 11) << g_shift) /* 5 bits of green */ \
+ | (((b) >> 11) << b_shift));/* 5 bits of blue */ \
((guint16 *)buf)[0] = rgb; \
buf += (bpp); \
break; \
\
case 16: \
- rgb = ( (((r) >> 11) << 11) /* 5 bits of red */ \
- | (((g) >> 10) << 5) /* 6 bits of green */ \
- | (((b) >> 11) << 0)); /* 5 bits of blue */ \
+ rgb = ( (((r) >> 11) << r_shift) /* 5 bits of red */
\
+ | (((g) >> 10) << g_shift)/* 6 bits of green */ \
+ | (((b) >> 11) << b_shift));/* 5 bits of blue */ \
((guint16 *)buf)[0] = rgb; \
buf += (bpp); \
break; \
I've committed your 24/32 bit patch and this one to CVS. A snapshot is
here:
http://www.meier-geinitz.de/sane/snapshots/sane-frontends-2003-01-24.tar.gz
Thanks for your work.
Bye,
Henning
