Hi, Some reference tests give a 1-pixel or very few pixel differences .
I'm not sure if this really indicates a problem in the WebKit code, or it indicates that we are just too strict not allowing even a very small percentage in pixel differences for this kind of tests. Should we tolerate a few pixel differences for reftests ? I have done some tests, and the test in  passes for any value of tolerance >= 0.00001% (with the GTK port). I'm inclined to allow a very small value, for example a 0.001% (that would be 100 times stricter than the tolerance value we use for the other tests) Regards -------  For example, this is happening in the GTK port: https://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20%28Tests%29/r192415%20%2812243%29/imported/blink/fast/canvas/canvas-clip-stack-persistence-diffs.html The diff image normalized (so you can see where is the diff): http://people.igalia.com/clopez/wkbug/151261/canvas-clip-stack-persistence-diff_normalized.png _______________________________________________ webkit-dev mailing list firstname.lastname@example.org https://lists.webkit.org/mailman/listinfo/webkit-dev