User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/62.0.3202.94 Safari/537.36 Steps to reproduce: This error only occurs when on windows. I am busy animating a gooey effect but when the animation starts it looks like the goo has an opacity but it should be a solid color. https://jsfiddle.net/lastgiven/kqmabvxs/2/ This is working on a Mac with version 57. Actual results: When you open the jsfiddle you will see that there is a grey and a black version both needs to be a solid color but the grey version has a white inside. Expected results: Both of the element should be solid color this is working on Mac but not on windows.

Regression range: https://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=99479edbee2a&tochange=e9337081c744

presumably either bug 924102 or bug 924103

Yeah -- looks like bug 924102 added an implementation and bug 924103 turned it on (per its first comment). So in other words, this is probably a bug in code that was written in bug 924102, and then activated (right afterwards) in bug 924103. Let's mark it as a regression from the first bug (where the code was written), since that seems more rational from a defect-tracking perspective, and that seems to be what we've done for the majority of other Moz2D regressions.

If it only affects Windows, it's probably a bug within the Direct2D FilterNode implementation. I'll try to create a reduced testcase.

This question and it's answer are likely worth a read: https://stackoverflow.com/questions/47531225/svg-gooey-effect-not-working-on-the-latest-version-of-firefox there's an analysis of the issue(s) in the answer.

The problem seems to be that if a filter produces an "alpha" value that is greater than 1, instead of clamping it at 1, we let it affect the rgb values. And then at some point we clamp all channels, but the damage has already been done. I think we pipe the color filter into a premultiplication filter, so it could be that premultiplication filter that multiplies the RGB channels with an unclamped alpha value.