RESOLVED FIXED 17997
Full Page Zoom: Artifacts in background images on mooseyard.com 
https://bugs.webkit.org/show_bug.cgi?id=17997
Summary Full Page Zoom: Artifacts in background images on mooseyard.com
Frederik De Bleser
Reported 2008-03-21 17:26:41 PDT
Using the new full page zoom feature in Webkit r31201, zooming twice on the page http://mooseyard.com/Jens/ (command-+ command-+) shows tearing artefacts between repeating background images, manifested as black lines. See the screenshot for details. Note that this happens only at some zoom levels, notably zoomed in twice and five times. Zooming out also results in artefacts.
Attachments
Screenshot of the site showing tearing artefacts (662.95 KB, image/png)
2008-03-21 17:27 PDT, Frederik De Bleser 		no flags
Details
This is a workaround patch. Just recording it. (1.27 KB, patch)
2008-03-24 19:41 PDT, Dave Hyatt 		no flags
DetailsFormatted DiffDiff
Patch (2.12 KB, patch)
2008-11-11 11:28 PST, Dave Hyatt 		sullivan: review+
DetailsFormatted DiffDiff
View All Add attachment proposed patch, testcase, etc.
Frederik De Bleser
Comment 1 2008-03-21 17:27:21 PDT
Created attachment 19947 [details] Screenshot of the site showing tearing artefacts
Dave Hyatt
Comment 2 2008-03-21 23:28:09 PDT
*** Bug 18003 has been marked as a duplicate of this bug. ***
Dave Hyatt
Comment 3 2008-03-21 23:28:52 PDT
*** Bug 17999 has been marked as a duplicate of this bug. ***
Dave Hyatt
Comment 4 2008-03-21 23:29:32 PDT
This bug appears to be Leopard-only, and it's an issue with CGContextDrawTiledImage The old Tiger code path (although slower) seems to be correct.
Dave Hyatt
Comment 5 2008-03-21 23:47:10 PDT
I can actually work around this, but it would mean taking the slow code path (and I think it would hurt performance way too much for zoomed pages to do this).
Dave Hyatt
Comment 6 2008-03-24 19:41:37 PDT
Created attachment 20018 [details] This is a workaround patch. Just recording it.
Dave Hyatt
Comment 7 2008-11-11 11:28:48 PST
Created attachment 25047 [details] Patch
John Sullivan
Comment 8 2008-11-11 11:41:56 PST
Comment on attachment 25047 [details] Patch Do you also want to check PLATFORM(MAC) anywhere? I see the existing #ifndef BUILDING_ON_TIGER does not do so, but maybe it should? John
Dave Hyatt
Comment 9 2008-11-11 11:51:56 PST
Fixed in r38309. Good question about PLATFORM(MAC). It depends on what version of CG ends up shipping with the next version of Safari on Windows whether or not the workaround will be needed for Windows.
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