Skia seems to turn off subpixel AA at a certain font size

RESOLVED WONTFIX

Status

()

Core
Graphics
P3
normal
RESOLVED WONTFIX
2 years ago
2 months ago

People

(Reporter: mstange, Unassigned, NeedInfo)

Tracking

Trunk
Points:
---

Firefox Tracking Flags

(firefox48 affected)

Details

(Whiteboard: [gfx-noted])

(Reporter)

Description

2 years ago
STR:
 1. On a HiDPI display, look at the "Home" heading on https://github.com/mozilla/rr/wiki
 2. Look at the slightly smaller text below it.
 3. Be very confused about the inconsistent use of subpixel AA.

Jeff says they may be switching to path rendering for large fonts, and path rendering will just use regular gray-scale anti-aliasing.
Firefox 51beta2 on Linux (Skia) does not respect subpixel rendering settings in drop-down elements at least.

https://drive.google.com/file/d/0Bxs_utDd2nQgcHRuUDZxRkdDbk0/view?usp=sharing

Bottom line produced by FF51beta2, top line — FF50 release.
(In reply to Timur Irikovich Davletshin from comment #2)
> Firefox 51beta2 on Linux (Skia) does not respect subpixel rendering settings
> in drop-down elements at least.
> 
> https://drive.google.com/file/d/0Bxs_utDd2nQgcHRuUDZxRkdDbk0/view?usp=sharing
> 
> Bottom line produced by FF51beta2, top line — FF50 release.

I think maybe you are experiencing a separate issue unrelated to this bug, possibly bug 1316523. Can you try nightly and see if it is better there?
Flags: needinfo?(timur.davletshin)
(In reply to Lee Salzman [:lsalzman] from comment #3)
> (In reply to Timur Irikovich Davletshin from comment #2)
> > Firefox 51beta2 on Linux (Skia) does not respect subpixel rendering settings
> > in drop-down elements at least.
> > 
> > https://drive.google.com/file/d/0Bxs_utDd2nQgcHRuUDZxRkdDbk0/view?usp=sharing
> > 
> > Bottom line produced by FF51beta2, top line — FF50 release.
> 
> I think maybe you are experiencing a separate issue unrelated to this bug,
> possibly bug 1316523. Can you try nightly and see if it is better there?

I tried latest nightly build — issue remains the same. What I also discovered that all builds starting with current beta have the same behavior. Switching back to Cairo doesn't fix it. IMHO this was introduced somewhere between current stable (50) and all newer releases. Maybe as result of preparations to switch to Skia.
Priority: -- → P3
Given that this appears to be based on the fact that Skia beyond a certain size threshold renders glyphs as paths, which is not likely to change within Skia in the future, I am going to mark this as wontfix for now. If it turns out to be some other issue later, we can reopen it.
Status: NEW → RESOLVED
Last Resolved: 2 months ago
Resolution: --- → WONTFIX
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