1546985 - Odd jaggies when rendering lowercase w in helvetica with stroke.

Status: RESOLVED FIXED

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

Description

[Blake Winton (:bwinton) (:☕️)]

c, v, and 4 are also a little odd…

Comment 1

[Blake Winton (:bwinton) (:☕️)]

(Andrew Osmond said that you might know something about this, @jkew? 🙂)

Oh, other info:

• macOS 10.14.4 (18E226)
• Firefox Nightly 68.0a1 (2019-04-25) (64-bit)
• Fails with Webrender both on and off.

Huh, also fails on Safari, so maybe not something we can do much about?

Comment 2

[Jonathan Kew [:jfkthame]]

Not specific to Helvetica, FWIW; try other sans-serifs like Arial or Impact.

It's a bit tricky to decide how best to handle sharp angles when stroking a path; see discussion of rounded vs beveled vs mitered joins, e.g. in cairo documentation, and parameters like the "miter limit". Possibly defaulting to rounded instead of mitered joins when stroking glyphs would be a safer option, although it's not obvious that there is any one "perfect" choice; alternatively, we could at least try reducing the miter limit.

Comment 3

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1546985 - Use JoinStyle::ROUND when stroking glyph outlines, to avoid artifacts at sharp corners. r=lsalzman

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/bd68b6dfd83e
Use JoinStyle::ROUND when stroking glyph outlines, to avoid artifacts at sharp corners. r=lsalzman

Comment 5

[Dorel Luca [:dluca]]

Backed out changeset bd68b6dfd83e (bug 1546985) for Reftest failures. CLOSED TREE

Log:
https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=242724072&repo=autoland&lineNumber=36877

Push with failures:
https://treeherder.mozilla.org/#/jobs?repo=autoland&revision=bd68b6dfd83e13a9ec3ff273b17fcb1992ae10ec

Backout:
https://hg.mozilla.org/integration/autoland/rev/d9e0ffa11ce7837c9dffbdeab702a37a50c9857f

Comment 6

[Jonathan Kew [:jfkthame]]

Oops - I forgot we have reftests that compare -webkit-text-stroke against SVG stroking, sorry. So we'll need to add stroke-linejoin=round to the SVG references there in order to match the rendering. I'll push that fix through try before re-landing.

Comment 7

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/0c0d1b6e9055
Use JoinStyle::ROUND when stroking glyph outlines, to avoid artifacts at sharp corners. r=lsalzman

Comment 8

[Arthur Iakab [arthur_iakab]]

https://hg.mozilla.org/mozilla-central/rev/0c0d1b6e9055