Re: Color swapping problem
- From: Owen Taylor <otaylor redhat com>
- To: Jim Buzbee <James Buzbee echostar com>
- Cc: gtk-list redhat com
- Subject: Re: Color swapping problem
- Date: 22 Dec 1999 11:37:35 -0500
Jim Buzbee <James.Buzbee@echostar.com> writes:
> I'm trying to track down the source of a color problem I'm having
> and I'm starting to think it may be in Gtk. Here's my situation. I
> working on an a x86 (Little Endian) processor but my graphics card
> is "broken" in that it insists on treating its frame buffer as Big
> Endian. I have successfully applied patches to my Xserver to account
> for this behavior and now most apps display fine (32 bit mode).
> Some apps however, have the red and blue colors still swapped. For
> example, If I run Netscape, all is well. If I run Mozilla, all the
> blues are red and all the reds are blue. If I run "xv -root
> image.jpg" the image is color-correct, If I run "Esetroot image.jpg"
> the reds and blues are swapped.
> Anyone have any insight? Are there some assumptions in the Gtk library about
> byte ordering?
I'm sort of puzzled as to what sort of video card could be worth
this much work considering the existance of good-performing
$20 cards that work out of the box... but anyways.
First, note Esetroot doesn't use GTK+ at all, so you have at
least two problems.
GTK+ should not be making any assumptions about byte ordering
in the frame buffer - after all it is quite possible to
remote display GTK+ from big-endian box to a little-endian
box. There are basically three possibilities that come
to mind as to what could be going on in your case:
- Your hacked server is not reporting the correct information
about the frame buffer. (The output of xdpyinfo may
- Your hacked server presents a combination that GdkRGB can't
handle properly because its rare enough that nobody has
ever bothered implementing it.
- There are bugs in GdkRGB that make it use the wrong
rendering code even though it has the code for the rendering
Could you provide:
- The output of gtk/testrgb.c from the GTK+ distribution
(you'll have to build GTK+ from source to get this)
- The output of 'xdpyinfo' (feel free to trim out obviously
- A description of the exact format of your frame buffer.
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