Now that bug 734082 is fixed and we have valid visual overflow rects on both SVG leaf and container frames, we can use these rects to minimize the size of the surfaces we create for SVG group opacity, masking and complex clipping. This should be a fairly substantial perf win on some SVG demos where we performed much worse than other implementations.
Created attachment 634713 [details] [diff] [review] patch Forgot to qrefresh.
It seems to me that this has made bug 614840 much more frequent
Interesting. Still, it's not due to the clip added in this patch clipping away stuff that shouldn't be clipped away. It's just an off-by-one difference to the R and B components of two pixels that are clearly well inside this additional clip, and only on Win6.1. I think we should just mark those test with fuzzy-if for that platform.
a 2 pixel fuzzy-if sounds good.
For me, this gave the IE Test Drive Helicopter demo in bug 608495 a huge 150x speedup. It seems to have also fixed the freezes that occurred when interacting with the maps on genomemaps.org reported in bug 754644.