Instead of the green conics, only grayscale ones. History: https://results.webkit.org/?suite=layout-tests&test=fast%2Fgradients%2Fconic-gradient-alpha.html
Oops, looks like I broke this. Happy to help fix it.
Any indication what’s going wrong yet?
It seems the generated gradient is now black&white: https://build.webkit.org/results/GTK%20Linux%2064-bit%20Release%20(Tests)/r264280%20(14625)/fast/gradients/conic-gradient-alpha-diffs.html
Maybe a bug in the blend function?
There are two problems: 1. Now the blend is done using premultiplied alpha, since the first color stop is #00FF0000, the premultiplied is just 0, so we always end up with black color. So, just changing to use blendWithoutPremultiply() would fix the bug but... 2. There's a bug in blendWithoutPremultiply(), from is used in both fromSRGB and toSRGB. Fixing 1 and 2 I get the right output, but the test doesn't pass yet, there's a one pixel difference for some reason.
Created attachment 404338 [details] Patch
Comment on attachment 404338 [details] Patch Nice! Thanks, this seems like a great fix.
Committed r264449: <https://trac.webkit.org/changeset/264449>