[cairo] cairo-xlib-surface.c:402: _swap_ximage_to_native:Assertion`NOT_REACHED' failed.

[Erik Ohrnberger]

> -----Original Message-----
> From: cairo-bounces at cairographics.org 
> [mailto:cairo-bounces at cairographics.org] On Behalf Of Damian Dixon
> Sent: Wednesday, November 22, 2006 4:07 AM
> To: Carl Worth; Daniel Amelang
> Cc: cairo at cairographics.org
> Subject: RE: [cairo] cairo-xlib-surface.c:402: 
> _swap_ximage_to_native:Assertion`NOT_REACHED' failed.
> 
> On Tue, 21 Nov 2006 10:46:03 -0800, "Daniel Amelang" wrote:
> >> Yes, but the issue is not the color depth, it's the bits per pixel.
> It
> >> is common to have 24-bit depth, yes, but less so to have 
> 24bpp. Cairo 
> >> is broken on X Servers that use 24bpp for Pixmaps, but it 
> works fine 
> >> on 32bpp servers that have 24-bit color depth.
> >
> >I wouldn't be very surprised to learn that that is the case.
> 
> Sorry I should have been a lot clearer about my use of depth and bpp.
> 
> I have a couple of X-Servers (6.4) running on Embedded 
> hardware that use
> 5-6-5 format packed for the Pixmap. I have about 15 different 
> X-Servers running on a number of different OS's and 
> processors (SPARC, PA-RISC II, XScale, AMD x64, Intel, MIPS).
> 
> I do admit that some of the systems I have are long in the 
> tooth but we have people using these systems...
> 
> I could probably try cario with some of these combinations 
> and provide some feedback. I am just not sure if I can commit 
> any significant time.
> 
> 
> >> At least that is my understanding. I'm a little concerned that Carl
> or
> >> Keith hasn't chimed in to give a more authoritative response.
> >
> >I haven't tested it at all, so you're already speaking from a more 
> >authoritative position I think. :-)
> >
> >As far as the idea of converting when transferring to/from the X 
> >server, I think that's what the patches here do (originally 
> written for 
> >the 8bpp case):
> >
> >	Cairo doesn't have 8-bit pseudocolor support
> >	https://bugs.freedesktop.org/show_bug.cgi?id=4945
> >
> 
> I have had a look at patch for 1.2.4 and most of the patch is 
> fine in that what the patch does in isolation looks ok with 
> the following
> observations:
> 
> There is a thread issue at the top of _get_clut_r3g3b2 that 
> needs to be sorted.
> 
> The patch should use XQueryColors rather then XQueryColor.
> 
> If the colourmap changes then there is no way of picking up 
> the change.
> Do we assume that the colourmap has been created specifically 
> for cairo and no-body else is using it? Possibly handle read 
> only colour maps differently from Read/Write colourmaps?
> 
> The colour matching may be an issue. What has been done looks 
> reasonable but I would like to see a reference to why this 
> particular approach was taken.
> 
> I don't know anything about Pixman and what formats it 
> supports to say if the checks made for the Visual class are 
> sufficient. I suspect that additional checks are required.
> 
> 
> 
> I doubt that 8-bit pseudocolor will be useable when 
> anti-aliasing is turned on. Dithering of colours will also 
> introduce artefacts which may not be acceptable.
> 
> I have found that when using 8-bit pseduocolour you want to 
> be able to specify the colour palette to ensure that you 
> don't get any odd fills or effects. In addition the colours 
> used by the program need to contained in the colourmap.
> 
> 
> >I honestly haven't looked at the issue close enough to made 
> a judgement 
> >call on whether those patches are in the right direction or 
> not. I'd be 
> >glad to hear opinions from people here, (as well as results from 
> >testing these patches for the 24-bpp problem in this thread).
> >
> >-Carl
> 
> Regards
> Damian
> _______________________________________________

OK, I've returned from out of town, and I'm wondering where this discussion
ended up.

Should I start hunting around for a source tarball for cairo-0.1.6 and it's
ebuild file for my gentoo system, or should I hang on and wait for a patch
to test (which I'd be glad to do), or how should I best approach this?

I also noticed that the bug that I submitted to bugzilla isn't there
anymore.  What happened?

Thanks in advance.
	Erik.