Created attachment 277883 [details]
Load the attached example HTML file in Safari 9 or Safari Technical Preview and enlarge the window.
Expected result: solid blurred rectangle with "Hello World" in the center.
Actual result: white grid lines appear in the rectangle.
Created attachment 277884 [details]
Works fine in latest Chrome and Firefox.
Why not use CSS filters? filter: blur(4px).
Thanks! :) CSS filters work great, but I hit this while messing around with SVG filters. (Specifically, I was hoping to use the edgeMode="duplicate" feature of <feGaussianBlur>).
Even with this fixed, I may use CSS filters anyway - I'm not sure what the performance characteristics of each are.