1308316 - Skia does not respect font hinting settings

Status: RESOLVED FIXED

(Core :: Graphics: Text, defect, P3)

Description

[Jan Alexander Steffens [:heftig]]

My system is configured not to hint text. The corresponding fontconfig snippet is:

  <match target="font">
    <edit name="hinting" mode="assign"><bool>false</bool></edit>
    <edit name="hintstyle" mode="assign"><const>hintnone</const></edit>
  </match>

GTK is also configured to disable hinting:
"gsettings get org.gnome.settings-daemon.plugins.xsettings hinting" returns 'none'.

The default Skia content renderer does not respect this setting, instead always choosing full hinting. Returning to the old Cairo content renderer fixes this.

Comment 1

[Lee Salzman [:lsalzman]]

This was regressed by bug 1278957 when we enabled Skia content.

Comment 2

[Lee Salzman [:lsalzman]]

Attachment: ensure Skia disables hinting if Fontconfig disables it

In the case that the scaler context requested hinting, but fontconfig explicitly disabled it, we weren't properly disabling hinting.

Comment 3

[Jan Alexander Steffens [:heftig]]

I did set hintstyle=hintnone, so shouldn't the old code have disabled hinting already?

Comment 4

[Jan Alexander Steffens [:heftig]]

Ah, never mind, I think I get it. The old code didn't touch the context's hinting mode at all if hinting=false.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/2321e1caa431
ensure Skia disables hinting if Fontconfig disables it. r=jrmuizel

Comment 6

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/2321e1caa431

Comment 7

[Lee Salzman [:lsalzman]]

Comment on attachment 8803481 [details] [diff] [review]
ensure Skia disables hinting if Fontconfig disables it

Approval Request Comment
[Feature/regressing bug #]: bug 1278957, so a regression was introduced starting with 51, which I would like to avoid introducing before 51 makes it to beta
[User impact if declined]: Linux users will not be able to disable font hinting for any/all fonts.
[Describe test coverage new/current, TreeHerder]: We don't currently have an explicit way to test different fontconfig settings within our testing framework, and this patch solely concerns fontconfig settings. However, the default fontconfig settings on Ubuntu disable hinting for some fonts at small sizes, so this gets some implicit testing from our existing reftests.
[Risks and why]: Low risk. This patch only affects Linux and will not otherwise impact other platforms. Even so, it just restores behavior to match what the previous Cairo font backend does, so is not introducing any new behavior.
[String/UUID change made/needed]: None

Comment 8

[Gerry Chang [:gchang]]

Comment on attachment 8803481 [details] [diff] [review]
ensure Skia disables hinting if Fontconfig disables it

Fix a regression related to Skia. Take it in 51 aurora.

Comment 9

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/releases/mozilla-aurora/rev/a730703766df

Comment 10

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

I've been seeing frequent Wr failures like https://treeherder.mozilla.org/logviewer.html#?job_id=3952526&repo=mozilla-aurora since this got pushed to aurora: https://treeherder.mozilla.org/#/jobs?repo=mozilla-aurora&fromchange=4e2043b472d20feba39a349b220742f463983a67&bugfiler&noautoclassify&filter-searchStr=85454b5eb1857d6f954b0f8216fb5cf259eab383&group_state=expanded&selectedJob=3952526


Backed out in https://hg.mozilla.org/releases/mozilla-aurora/rev/8da98b978cfc to see if that helps.

Comment 11

[Lee Salzman [:lsalzman]]

(In reply to Wes Kocher (:KWierso) from comment #10)
> I've been seeing frequent Wr failures like
> https://treeherder.mozilla.org/logviewer.html#?job_id=3952526&repo=mozilla-
> aurora since this got pushed to aurora:
> https://treeherder.mozilla.org/#/jobs?repo=mozilla-
> aurora&fromchange=4e2043b472d20feba39a349b220742f463983a67&bugfiler&noautocla
> ssify&filter-
> searchStr=85454b5eb1857d6f954b0f8216fb5cf259eab383&group_state=expanded&selec
> tedJob=3952526
> 
> 
> Backed out in
> https://hg.mozilla.org/releases/mozilla-aurora/rev/8da98b978cfc to see if
> that helps.

I would think this is a red herring. The assertion "Assertion failure: mFormat != gfx::SurfaceFormat::UNKNOWN (Could not find SurfaceFormat for visual!)" will gets triggered if when a window is resized or opened, it can't find one of our internal surface formats that match the X window's visual. My suspicion would be that it is some other patch.

Comment 12

[Lee Salzman [:lsalzman]]

I kicked off some retriggers after the backout of my patch on aurora and it's still happening, so at least the evidence seems to support my innocence. :) My best guess would be bug 1278443 which got pushed to aurora at the same time as my patch.

Comment 13

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

Relanded since this wasn't at fault: https://hg.mozilla.org/releases/mozilla-aurora/rev/96b6a1a83bd74da807a67bb9449bc7158f6ee2cb