1553818 - Some sites such as https://forums.overclockers.co.uk/ seem to have blurrier fonts

Status: VERIFIED FIXED

(Core :: Graphics: Text, defect, P1)

Description

[Darkspirit]

Attachment: Screenshot.png

https://www.reddit.com/r/firefox/comments/bs0duk/anyone_else_with_wr_enabled_noticed_text_looks/

So I've enabled WR and I'm really loving it, the difference on heavier sites is very noticeable. However, I noticed some sites such as OcUK Forums seems to have blurrier fonts with WR enabled (WR off above, WR on below): https://i.imgur.com/E8Pt313.png

Turning WR off makes the text clear again. This does not happen to every site, all other sites I visit, fonts looks completely fine. It's just this website that for some reason I've noticed it.

Confirmed with 67 and 69 on Win10, GTX1060.

Comment 1

[kirayahiroz]

Hi, just wanted to add that was my Reddit/OcUK post, so to add more detail this is with FF 67 release with W10, GTX1080 Ti. I've also confirmed it with another PC using W10, AMD 5670.

Comment 2

[Jessie [:jbonisteel] pls NI]

Hey Lee - can you take a look at this please?

Comment 3

[Lee Salzman [:lsalzman]]

If you disable WebRender, and you disable Direct2D as well so there is no HWA, what does it look like?

Comment 4

[Darkspirit]

Attachment: basic,wr,d3d11.png

Comment 5

[Lee Salzman [:lsalzman]]

It seems like the result is consistent with what Skia rendering is giving us. Can you please also add in the about:support for the d3d11 case? I am also curious what the result looks like in Chromium, maybe closer to the Skia case?

Comment 6

[Darkspirit]

Attachment: comment4_d3d11_aboutsupport.txt

(Win10 1809, GTX1060, 2560x1440, Dell UltraSharp U2515H (117.5 DPI))

Comment 7

[Darkspirit]

Attachment: basic,wr,d3d11,chrome-dev.png

Comment 8

[Jessie [:jbonisteel] pls NI]

Lee - any new ideas here?

Comment 9

[Lee Salzman [:lsalzman]]

The font used is Verdana, which gets forced to use GDI rendering. In bug 1323587, Mason hard-coded the gamma to 2.3 for GDI fonts, based on a reading of Skia's code at https://searchfox.org/mozilla-central/source/gfx/skia/skia/src/ports/SkFontHost_win.cpp#1079. However, it turns out that we rather need to use the ClearType value in the code nearby, which is a much lower gamma value by default, and in any case is a system parameter.

It turns out that our Skia and WebRender rendering of GDI fonts looks far bolder than the Direct2D reference case as a result. This has been the case since bug 1323587.

I have a fix in progress...

Comment 10

[Lee Salzman [:lsalzman]]

Attachment: Bug 1553818 - use GDI ClearType contrast for GDI font gamma. r?jrmuizel

Comment 11

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f03d8ccb0864
use GDI ClearType contrast for GDI font gamma. r=jrmuizel

Comment 12

[Daniel Varga [:dvarga]]

https://hg.mozilla.org/mozilla-central/rev/f03d8ccb0864

Comment 13

[Lee Salzman [:lsalzman]]

Comment on attachment 9080168 [details]
Bug 1553818 - use GDI ClearType contrast for GDI font gamma. r?jrmuizel

Beta/Release Uplift Approval Request

• User impact if declined: Windows users will see GDI fonts with incorrect gamma when using WebRender or Skia, that looks noticeably different than our normal output with the Direct2D backend.
• 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: bug 1568841
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): GDI fonts under WebRender and Skia now more closely match the rendering output with our Direct2D backend.
• String changes made/needed:

Comment 14

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9080168 [details]
Bug 1553818 - use GDI ClearType contrast for GDI font gamma. r?jrmuizel

Fixes a regression in font rendering for some Windows users with WebRender enabled. Approved for 69.0b9.

Comment 15

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-beta/rev/a5573dc63113

Comment 16

[Daniel Cicas [:dcicas], Release QA]

Hello,

I can confirm that this issue is fixed on Fx 69.0b9 and Fx 70.0a1 BuildID: 20190731215544. I verified using Windows 10 x64 1050 GTX.