User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:68.0) Gecko/20100101 Firefox/68.0

Steps to reproduce:

With WebRender enabled by gfx.webrender.all, try to turn off subpixel antialiasing for text by:

1. ClearType Text Tuner of Windows, choosing the third option at the third step,

OR

2. Set gfx.font_rendering.cleartype_params.cleartype_level to 0 in about:config.

Actual results:

Text is still rendered with subpixel antialiasing.

Expected results:

With WebRender disabled, either of these methods will make Firefox use grayscale antialiasing instead of subpixel.

https://hg.mozilla.org/mozilla-central/rev/be975934ff0a

This probably warrants uplifting to 67 (I presume it is affected, didn't test). Lee, if you agree, can you request uplift?

Comment on attachment 9058366 [details]
Bug 1544188 - check cleartype level for WR DWrite fonts. r?jfkthame

Beta/Release Uplift Approval Request

• User impact if declined: WebRender users who have disabled ClearType (subpixel anti-aliasing) via the Windows font tuner will still see ClearType enabled, as the ClearType settings won't be properly respected.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Just checks an OS setting for font rendering when WebRender is enabled that shouldn't affect most users.
• String changes made/needed:

Comment on attachment 9058366 [details]
Bug 1544188 - check cleartype level for WR DWrite fonts. r?jfkthame

Low-risk targeted fix for webrender on Windows, uplift approved for 67 beta 13, thanks.

https://hg.mozilla.org/releases/mozilla-beta/rev/a3857b3191a4

Marking this as qe-verify- based on comment 6.