Bug 15744

Summary:	[Xlib] rotation confuses the backend
Product:	cairo	Reporter:	Benjamin Otte <otte>
Component:	xlib backend	Assignee:	Carl Worth <cworth>
Status:	RESOLVED FIXED	QA Contact:	cairo-bugs mailing list <cairo-bugs>
Severity:	normal
Priority:	medium
Version:	1.6.5
Hardware:	Other
OS:	All
Whiteboard:
i915 platform:		i915 features:
Bug Depends on:	15369
Bug Blocks:
Attachments:	testcase

Description Benjamin Otte 2008-04-28 07:01:41 UTC

Created attachment 16215 [details]
testcase

Here's a magic matrix that makes the Xlib backend screw up. The image backend and the X fallback code renders it fine.

I shortly tried some obvious rotations, but couldn't make it fail, so I pasted the matrix verbatim into the test. But I did enough of a job already, the initial test was 300 lines long. ;)

I also shortly checked various other clipping and extend-none related bugs, but they never where xlib specific, so I filed a new bug.

Comment 1 Benjamin Otte 2008-04-28 07:35:13 UTC

Owen mentioned that this is related (likely the same as) bug 15369, but I wasn't sure how they affect each other, so I'm not amrking this a duplicate.

Comment 2 Andrea Canciani 2011-03-18 04:57:28 UTC

The problem cannot be reproduced with current Cairo/Pixman/X
(and Xlib, XCB and image now share the matrix computation code).

The specific commit which actually fixed this has probably been
pushed long ago, but I cannot bisect it easily because the current
autotools suite does not work smoothly on cairo 1.6
(./configure dies with an error).

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