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.
Created attachment 3205 [details] [review] proposed fix
Created attachment 3366 [details] Screenshot showing the bug Reattching the screenshot since the old one was apparently lost in the disk crash
Lots of people are hitting this, so I'm making it block 6.9/7.0
*** Bug 5108 has been marked as a duplicate of this bug. ***
*** Bug 4152 has been marked as a duplicate of this bug. ***
*** Bug 5152 has been marked as a duplicate of this bug. ***
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].
Created attachment 4031 [details] [review] New patch There is another instance of the same bug.
Chris Aillon happened to have a system displaying this bug, and the patch does indeed fix it.
that makes you my new hero. applied, thanks!
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