1576553 - stroked text with ligature painted incorrectly when selection intersects ligature

Status: RESOLVED FIXED

(Core :: Layout: Text and Fonts, defect, P3)

Description

[Cameron McCormack (:heycam)]

Attachment: test

See the attached test case, which hopefully renders with a font that has an ff or fi or ffi ligature. Selecting part of that ligature causes some parts of the text to be painted in the wrong position.

I could only reproduce this with -webkit-text-fill-color: transparent.

Comment 1

[Jonathan Kew [:jfkthame]]

Cute! I think there's a simple patch that will fix this; we should also add a reftest to cover it.

Comment 2

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1576553 - Partial ligatures need to be drawn if either GLYPH_FILL or GLYPH_STROKE is in effect. r?heycam

Comment 3

[Jonathan Kew [:jfkthame]]

This fixes the behavior in my local testing; I'll put up a reftest patch in a while.

Comment 4

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1576553 - Add reftest. r?heycam

Comment 5

[Jonathan Kew [:jfkthame]]

The reftest is likely to have a little bit of "fuzz" in the antialiasing at the edges of the selected range, because of drawing adjacent (touching) parts of the text in separate operations, but it should be unimportant; I'll get tryserver to confirm how much fuzz is needed.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d653382c7997
Partial ligatures need to be drawn if either GLYPH_FILL or GLYPH_STROKE is in effect. r=heycam
https://hg.mozilla.org/integration/autoland/rev/bc36c4359eef
Add reftest. r=heycam

Comment 7

[Andreea Pavel [:apavel]]

Backed out for failing reftest at 1576553-1.html

Push with failures: https://treeherder.mozilla.org/#/jobs?repo=autoland&group_state=expanded&resultStatus=testfailed%2Cbusted%2Cexception&revision=bc36c4359eefdd8bf946de2a6c95e5f9a044cbee&selectedJob=263601747

Tier1 failure log: https://treeherder.mozilla.org/logviewer.html#/jobs?job_id=263600530&repo=autoland&lineNumber=26730

Backout: https://hg.mozilla.org/integration/autoland/rev/6097272103defa58d5710fd7f8170db3d756462f

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/ae2021d2c744
Partial ligatures need to be drawn if either GLYPH_FILL or GLYPH_STROKE is in effect. r=heycam
https://hg.mozilla.org/integration/autoland/rev/713c95e01d1e
Add reftest. r=heycam

Comment 9

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/ae2021d2c744
https://hg.mozilla.org/mozilla-central/rev/713c95e01d1e