Bug 3944

Summary: GdkPixbuf rendering with fbCompositeGeneral and shadowfb in CVS HEAD
Product: xorg Reporter: Søren Sandmann Pedersen <soren.sandmann>
Component: Server/GeneralAssignee: Xorg Project Team <xorg-team>
Status: RESOLVED FIXED QA Contact:
Severity: normal    
Priority: high CC: henri.ala-peijari, j, kokje, wriede
Version: git   
Hardware: x86 (IA32)   
OS: Linux (All)   
Whiteboard:
i915 platform: i915 features:
Bug Depends on:    
Bug Blocks: 1690    
Attachments:
Description Flags
Screenshot showing the bug
none
A patch
none
New patch none

Description Søren Sandmann Pedersen 2005-08-02 04:53:01 UTC 
With the new scanline based fbCompositeGeneral and a packed 24 bit shadowFB,
GdkPixbuf rendering is broken as the soon-to-be-attached screenshot shows.

GdkPixbufs are non-premultiplied RGBA images. To make RENDER deal with this
format, gtk+ renders gdkpixbufs with the image itself as the image, ie.:

   RGBA-image IN RGBA-image OVER destination

where the IN-operation makes sure the image that is composited OVER the
destination, will actually be premultiplied.

I have verified that the bug was introduced with the commit of the scanline
based fbCompositeGeneral.
Comment 1 Søren Sandmann Pedersen 2005-08-02 04:53:32 UTC 
Created attachment 3205 [details] [review]
proposed fix
Comment 2 Søren Sandmann Pedersen 2005-09-22 11:08:22 UTC 
Created attachment 3366 [details]
Screenshot showing the bug

Reattching the screenshot since the old one was apparently lost in the disk
crash
Comment 3 Søren Sandmann Pedersen 2005-11-30 06:25:56 UTC 
Lots of people are hitting this, so I'm making it block 6.9/7.0
Comment 4 Adam Jackson 2005-11-30 15:56:51 UTC 
*** Bug 5108 has been marked as a duplicate of this bug. ***
Comment 5 Adam Jackson 2005-11-30 15:58:06 UTC 
*** Bug 4152 has been marked as a duplicate of this bug. ***
Comment 6 Adam Jackson 2005-11-30 15:59:17 UTC 
*** Bug 5152 has been marked as a duplicate of this bug. ***
Comment 7 Søren Sandmann Pedersen 2005-12-08 06:30:49 UTC 
Created attachment 4030 [details] [review]
A patch

Note: This patch is untested, but I am pretty confident in it anyway, because
the bug it fixes

- would have symptoms like those reported
- would only happen on 24 bit packed framebuffers
- was introduced with the scanline based compositing.

all of which are consistent with what people have reported.

[If I get the server to compile on my system, I'll test it].
Comment 8 Søren Sandmann Pedersen 2005-12-08 06:38:19 UTC 
Created attachment 4031 [details] [review]
New patch

There is another instance of the same bug.
Comment 9 Søren Sandmann Pedersen 2005-12-09 03:51:34 UTC 
Chris Aillon happened to have a system displaying this bug, and the patch does
indeed fix it.
Comment 10 Adam Jackson 2005-12-09 06:29:11 UTC 
that makes you my new hero.

applied, thanks!

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