1912431 - Some Unicode pictograms are not shown if they were first drawn with globalAlpha=0

Status: RESOLVED FIXED

(Core :: Graphics: Canvas2D, defect)

Description

[Martynas Majeris]

Reproduce:

1. Create a <canvas> element
2. Set context.globalAlpha = 0.
3. Draw text which includes Unicode pictograms, e.g. "🕛".
4. Set context.globalAlpha = 1.
5. Draw text which includes Unicode pictograms, e.g. "🕛".

Live demo:
https://codepen.io/team/amcharts/pen/ExBvOod/782ea4f2c0233491a115df464405c164?editors=0010

Actual outcome:

• The first text is all invisible (correct).
• Only regular characters are visible in the second text, Unicode pictograms (e.g. 🕛) are still invisible, even though they take up space. (bug)

Desired outcome:

• All text, including Unicode pictograms should have been visible.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

The Bugbug bot thinks this bug should belong to the 'Core::Graphics: Canvas2D' component, and is moving the bug to that component. Please correct in case you think the bot is wrong.

Comment 2

[Mayank Bansal]

Can confirm.
Bisection:

Bug 1875670 - Add a cache for rasterized COLRv1 glyphs, because fully redrawing them on each use can be expensive. r=gfx-reviewers,lsalzman
Differential Revision: https://phabricator.services.mozilla.com/D200139

Comment 3

[Mayank Bansal]

Attachment: Reporters Standalone Testcase.html

Comment 4

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1875670

Comment 5

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1912431 - Don't apply global alpha when creating a cached color glyph. r=#gfx-reviewers

The reftest here currently fails on Android for what appears to be an
unrelated reason: reftest-analyzer shows that in the reference case,
all but the last line of text is completely missing.

I'm not sure what's failing there (but it fails similarly without this
patch, anyhow); we should investigate that as a separate bug.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/b1612e480369
Don't apply global alpha when creating a cached color glyph. r=gfx-reviewers,lsalzman

Comment 7

[Norisz Fay [:noriszfay]]

Backed out for causing reftest failures on 1912431-emoji-globalAlpha.html

Backout link

Push with failures

Failure log

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6615415921d9
Don't apply global alpha when creating a cached color glyph. r=gfx-reviewers,lsalzman

Comment 9

[Atila Butkovits]

Backed out for causing failures at globalAlpha.html

Backout link: https://hg.mozilla.org/integration/autoland/rev/ba1282f96e4613a1e25525ba8abcdb58217a4e10

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=6615415921d9fa96b53353d2f7cb4d2f9b2a3913&selectedTaskRun=Sc-hHTtkREeHfb4QoDahsA.0

Failure log: https://treeherder.mozilla.org/logviewer?job_id=470141575&repo=autoland&lineNumber=2610

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/05e409210f6b
Don't apply global alpha when creating a cached color glyph. r=gfx-reviewers,lsalzman

Comment 11

[Narcis Beleuzu [:NarcisB]]

Backed out for reftest failure on 1912431-emoji-globalAlpha.html

Backout link: https://hg.mozilla.org/integration/autoland/rev/4a870b447bf201ab4e151d9f568af2aec2292d7a
Log link: https://treeherder.mozilla.org/logviewer?job_id=470161613&repo=autoland&lineNumber=5622

Comment 12

[Jonathan Kew [:jfkthame]]

Sigh.... so many different backends, with subtly different rendering... :(. Tweaked the fuzz numbers again.

Comment 13

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/f189c9ba3746
Don't apply global alpha when creating a cached color glyph. r=gfx-reviewers,lsalzman

Comment 14

[Cristian Tuns]

Backed out for causing reftest failures in 1912431-emoji-globalAlpha.html

• Backout link
• Push with failures
• Failure Log
• Failure line: REFTEST TEST-UNEXPECTED-PASS | gfx/tests/reftest/1912431-emoji-globalAlpha.html == gfx/tests/reftest/1912431-emoji-globalAlpha-ref.html | image comparison, max difference: 0, number of differing pixels: 0

Comment 15

[Jonathan Kew [:jfkthame]]

Huh, so the Android failure (bug 1912718) doesn't always happen.

Comment 16

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a39f4090a526
Don't apply global alpha when creating a cached color glyph. r=gfx-reviewers,lsalzman

Comment 17

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/a39f4090a526

Comment 18

[BugBot [:suhaib / :marco/ :calixte]]

The patch landed in nightly and beta is affected.
:jfkthame, is this bug important enough to require an uplift?

• If yes, please nominate the patch for beta approval.
• If no, please set status-firefox130 to wontfix.

For more information, please visit BugBot documentation.

Comment 19

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1912431 - Don't apply global alpha when creating a cached color glyph.

The reftest here currently fails on Android for what appears to be an
unrelated reason: reftest-analyzer shows that in the reference case,
all but the last line of text is completely missing.

I'm not sure what's failing there (but it fails similarly without this
patch, anyhow); we should investigate that as a separate bug.

Original Revision: https://phabricator.services.mozilla.com/D219024

Comment 20

[Phabricator Automation]

beta Uplift Approval Request

• User impact if declined: color glyphs (e.g. emoji) in <canvas> may be missing in some cases
• Code covered by automated testing: yes
• Fix verified in Nightly: no
• Needs manual QE test: no
• Steps to reproduce for manual QE testing: n/a
• Risk associated with taking this patch: minimal
• Explanation of risk level: trivial fix when creating a cached glyph image
• String changes made/needed: none
• Is Android affected?: yes

Comment 21

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-beta/rev/f238b4e2b49e

Comment 22

[Ryan VanderMeulen [:RyanVM]]

Worth an ESR128 uplift also? Note that we would also need bug 1902253 for it to graft cleanly.

Comment 23

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1912431 - Don't apply global alpha when creating a cached color glyph.

The reftest here currently fails on Android for what appears to be an
unrelated reason: reftest-analyzer shows that in the reference case,
all but the last line of text is completely missing.

I'm not sure what's failing there (but it fails similarly without this
patch, anyhow); we should investigate that as a separate bug.

Original Revision: https://phabricator.services.mozilla.com/D219024

Comment 24

[Phabricator Automation]

esr128 Uplift Approval Request

• User impact if declined: color glyphs may fail to paint in canvas when globalAlpha has been used
• Code covered by automated testing: yes
• Fix verified in Nightly: yes
• Needs manual QE test: no
• Steps to reproduce for manual QE testing: n/a
• Risk associated with taking this patch: minimal
• Explanation of risk level: trivial (one-liner) fix when generating cached glyph image
• String changes made/needed: none
• Is Android affected?: yes

Comment 25

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-esr128/rev/bc9f4040eb4d