Bug 41745

Summary:	Downscaling with ImageSurface
Product:	cairo	Reporter:	Dusan Maliarik <dusan.maliarik>
Component:	image backend	Assignee:	Carl Worth <cworth>
Status:	RESOLVED FIXED	QA Contact:	cairo-bugs mailing list <cairo-bugs>
Severity:	normal
Priority:	medium	CC:	hib, manisandro, soren.sandmann, tweenk.pl
Version:	1.10.3
Hardware:	Other
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:
Attachments:	Downscaling patch

Description Dusan Maliarik 2011-10-13 06:43:25 UTC

I found lots of discussion, and many proposed solutions, and patches to this problem. It seems that many (mozilla, poppler, others?) using cairo (or pixman) is maintaing some patch that fixes the ugly downscaling output.

Related information for reference:
https://bugzilla.mozilla.org/show_bug.cgi?id=486918
http://lists.cairographics.org/archives/cairo/2009-July/017637.html
http://lists.cairographics.org/archives/cairo/2009-November/018561.html
http://lists.freedesktop.org/archives/cairo/2011-July/022142.html

Comment 1 Krzysztof Kosiński 2013-04-26 14:12:11 UTC

Created attachment 78522 [details] [review]
Downscaling patch

Pixman now implements convolutions, so this bug should be rather easy to fix. Here is an example patch.

Comment 2 Bryce Harrington 2013-09-27 06:45:22 UTC

This patch has landed in trunk, and will be part of the next release.

Comment 3 Bryce Harrington 2014-07-11 19:43:38 UTC

The patch had to be reverted.
See http://thread.gmane.org/gmane.comp.lib.cairo/24825/focus=24856

Another patch has been proposed and is under consideration:
http://thread.gmane.org/gmane.comp.lib.cairo/24870

Comment 4 Bryce Harrington 2014-07-25 22:23:36 UTC

The aforementioned patch has landed; please re-test and share feedback here or on the mailing list.

Comment 5 Bryce Harrington 2014-07-25 22:24:35 UTC

I'm going to close this bug as fixed, assuming the new downscaling patch does the trick.  If it does not, or if there are any concerns, please reopen this patch so further investigation can be done.

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