[wpe-2.38] Appearance of darker shades in SVG lightning filter

[amol-virnodkar-infosys]

Appearance of darker shades in SVG lightning filter with WPE 2.38, when ACT-1345 test case is executed from BBC cert suite. To reproduce the issue, use WPE 2.38 and run ACT-1345 test case:

https://certification.bbctvapps.co.uk/act/client/ in the WPE-WebKit-based browser https://certification.bbctvapps.co.uk/act/portal/ locally and pair the two

WPE 2.38

[pgorszkowski-igalia]

It seems that in case of 2.38 the reason of the darker results is change: https://bugs.webkit.org/show_bug.cgi?id=234118.

This change turns off possibility to use linearRGB colorspace in case of WPE and cairo. I will continue my investigation would it be possible to turn it on without any regression in 2.38 (the test case passes with expected results if I turn it on but I need to consult this with SVG expert)

[pgorszkowski-igalia]

I created a bug report about this case in upstream: https://bugs.webkit.org/show_bug.cgi?id=268537 and created PR which fixes it: https://github.com/WebKit/WebKit/pull/23663. The fix is waiting for review. After merging it in upstream, I will bakcport it to 2.38 and 2.42

[pgorszkowski-igalia]

https://github.com/WebKit/WebKit/pull/23663 is merged, but unfortunately there are a lot of difference between upstream and wpe-2.38, so I will have to reimplement few things. I will try to provide a PR for wpe-2.38 as soon as possible

[pgorszkowski-igalia]

Fix from upstream is backported to wpe-2.38: https://github.com/WebPlatformForEmbedded/WPEWebKit/pull/1287

@amol-virnodkar-infosys: please check and verify.

[amol-virnodkar-infosys]

We retested this issue using the fix in the PR: https://github.com/WebPlatformForEmbedded/WPEWebKit/pull/1287 and could not reproduce the issue.

Please find below test result of the ACT-1345 using the fix.

[pgorszkowski-igalia]

ok, so I close this ticket.