test case: http://glimr.rubyforge.org/cake/canvas.html, choose ImageTest in the combo box The image rotates and moves very slowly and with a lot of artifacts and flickers, compared to Safari/Chrome.
Confirmed. Here is the direct link to the test : http://glimr.rubyforge.org/cake/canvas.html#KeyboardTest The image should not be clipped when transformed.
Created attachment 48713 [details] Fix GraphicsContext::roundToDevicePixels in Qt I found the source of the problem - our GraphicsContext::roundToDevicePixels function is wrong, as it doesn't make the right calculation in the case of rotating images. The attached fix makes that function completely equivalent to the CG implementation, and rotating canvas images now look fine!
Nice! I've seen this bug a few times in the past. Any chance that this is also covered by an existing but currently skipped canvas layout test? Adding Ariya to CC, he's more qualified than me to review this piece :)
Comment on attachment 48713 [details] Fix GraphicsContext::roundToDevicePixels in Qt Looks good.
Comment on attachment 48713 [details] Fix GraphicsContext::roundToDevicePixels in Qt Clearing flags on attachment: 48713 Committed r54811: <http://trac.webkit.org/changeset/54811>
All reviewed patches have been landed. Closing bug.