64237 2011-07-10 05:10:03 -0700 [Skia] SVGMask fails on transformations 2013-04-09 13:01:57 -0700 1 1 1 Unclassified WebKit SVG 528+ (Nightly build) Unspecified Unspecified RESOLVED WONTFIX P2 Normal --- 1 krit webkit-unassigned caryclark guanqun.lu pkasting schenney sky zimmermann oldest_to_newest 434545 0 100222 krit 2011-07-10 05:10:03 -0700 Created attachment 100222 Mask on object that gets skewed SVGMask fails on transformations, independent what gets transformed. This is caused by our transformation algorithm in WebCore/rendering/SVGImageBufferTools.cpp/.h. We draw the content of a mask into a new ImageBuffer. This ImageBuffer is used as a mask. To prevent any pixelation, we draw the mask in the screen space instead of the userspace of the target. Means we transform the CTM of the ImageBuffer context to the transformation base that is visible on the screen before drawing the mask content. That forces us to transform the CTM of our canvas to the screens CTM as well during the masking operation and unapply the CTM transformation afterwards. For some reason this doesn't work on Skia quite well. I attached an example. In this example the mask gets skewed by 22.5 degree. On Skia the skewing is 45 degree. Looks like the transformation that is used to change from user space to screen space gets applied twice. 434546 1 krit 2011-07-10 05:11:51 -0700 Adding author of Skias clipToImageBuffer code. 459102 2 krit 2011-08-30 12:51:01 -0700 I'll try to catch the problem once I got chromium skis working on Mac. 100222 2011-07-10 05:10:03 -0700 2011-07-10 05:10:03 -0700 Mask on object that gets skewed svg-mask.svg image/svg+xml 322 krit PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHhtbG5zOnhsaW5rPSJodHRw Oi8vd3d3LnczLm9yZy8xOTk5L3hsaW5rIj4KPGRlZnM+CjxtYXNrIGlkPSJtYXNrIiBtYXNrQ29u dGVudFVuaXRzPSJvYmplY3RCb3VuZGluZ0JveCI+CiAgICA8Y2lyY2xlIGN4PSIuNTAiIGN5PSIu NTAiIHI9Ii41MCIgZmlsbD0id2hpdGUiLz4KPC9tYXNrPgo8L2RlZnM+CjxnIHRyYW5zZm9ybT0i c2tld1goMjIuNSkiPgo8cmVjdCB3aWR0aD0iMTAwcHgiIGhlaWdodD0iMTAwcHgiIGZpbGw9Imdy ZWVuIiBtYXNrPSJ1cmwoI21hc2spIi8+CjwvZz4KPC9zdmc+Cg==