[Cairo] Demo program ..

[Carl Worth]

On Sep 23, Lars Segerlund wrote:
 >  Here is the last part in steppign through the program cairo-demo
 >  ... when it crashes, I just find it an interesting place to get an
 >  error.
 > X Error of failed request:  BadDrawable (invalid Pixmap or Window parameter)
 >   Major opcode of failed request:  14 (X_GetGeometry)
 >   Resource id in failed request:  0x4a00003
 >   Serial number of failed request:  42
 >   Current serial number in output stream:  42

I was able to replicate this problem with an XFree86 4.2 server.

I was able able to make this problem go away by reversing the memory
leak patch from the following message:

	http://cairographics.org/pipermail/cairo/2003-September/000510.html

(That is, removing the call to XFreePixmap in
cairo_surface_create_similar_solid removes the protocol error).

I'm not committing that change because we've already verified that it
causes huge memory leaks, (as it should). It may be that there's some
other bug in Cairo from a code path that's only triggered on the older
server. Or it may be that there is a bug in the older server where the
pixmap drops a reference count somewhere. I don't know for sure yet.

Regardless, without the call the XFreePixmap I did get the example
programs to run with the 4.2 server, but they still don't work. Most
of them open up a blank window, but cairo-knockout dies succeed in
drawing a few circles, (the checkered background is missing though).

So, obviously, support for older servers isn't quite all there yet.

-Carl