Bug 26063

Created attachment 32657 [details] [review]
flush: only call QPainter::end() & QPainter::begin() if we own QPainter pointer; otherwise call QPainter::restore()

Created attachment 32658 [details] [review]
finish: remove call to QPainter::restore() here; see patch above

O, well, 'cairo_qpainter_' should be replaced with 'cairo_qt_' in the patches.

$ sed -e "s/cairo_qpainter_/cairo_qt_/g" -i qt-*.diff

The XErrors I see are:

X Error: BadMatch (invalid parameter attributes) 8
Extension: 149 (RENDER)
Minor opcode: 4 (RenderCreatePicture)
Resource id: 0x104

X Error: RenderBadPicture (invalid Picture parameter) 171
Extension: 149 (RENDER)
Minor opcode: 23 (RenderCompositeGlyphs8)
Resource id: 0x1803105 

X Error: RenderBadPicture (invalid Picture parameter) 171
Extension: 149 (RENDER)
Minor opcode: 7 (RenderFreePicture)
Resource id: 0x1803bdb 


Any ideas?

Taken the flush() fixes (with a modification to balance ->restore()). As for the BadMatch, can you run xtrace and extract the erroneous sequence?

commit 6950b233e41a0c926465728c37f9bc5512f2844b
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Fri Jan 15 14:25:16 2010 +0000

    qt: Make flush() robust.
    
    Hanno Meyer-Thurow reported in
    
      http://bugs.freedesktop.org/show_bug.cgi?id=26063
      [PATCH] various fixes to cairo-qt
    
    a few issues related to _cairo_qt_surface_flush() where firefox was
    crashing after being built to use cairo-qt.
    
    This is an amalgam of those patches that hopefully address the issue.

xtrace does not show anything. Or I just prefer gdb. :)

Still, I have not done X Error debugging before. And google just does not help me to identify the environment variable to get xlib (error reporting) synchronized. I will be back if I find some useful docs.

Okay, I got it synchronized and it seems to happen in _cairo_qt_surface_show_glyphs. The X Errors are inside the printf calls now, see below. But it does not always happen.
The testcase I have is simpe, open google.com. There are transparent texts that fade in, perhaps?

And I just saw that create_with_image does not create a xlib surface? But adding the creation there, too, does not help with the X Errors. Well, that is all I can help here, sorry.

___
cairo-qt: xlib start
X Error: BadMatch (invalid parameter attributes) 8
Extension:    149 (RENDER)
Minor opcode: 4 (RenderCreatePicture)
Resource id:  0x104
X Error: RenderBadPicture (invalid Picture parameter) 171
Extension:    149 (RENDER)
Minor opcode: 5 (RenderChangePicture)
Resource id:  0x104
X Error: RenderBadPicture (invalid Picture parameter) 171
Extension:    149 (RENDER)
Minor opcode: 23 (RenderCompositeGlyphs8)
Resource id:  0x1a00168
cairo-qt: xlib stop

Well, since the initial bugreport is fixed this can be closed/fixed. Thank you!
For the glyphs errors one may open another bugreport with better info or patch.

O well, before this bug is closed I want to add some info about the X Errors.
They happen where opacity is set to zero. Any higher value and the X Errors disappear.

Okay, synchronized my cairo-qt version to cairo head. Now, the X Errors are gone.

Closing as FIXED, thank you for your help!