1796648 - Drop any SVG table from downloaded fonts if OpenType-SVG rendering is disabled

Status: RESOLVED FIXED

(Core :: Graphics: Text, defect)

Description

[Jonathan Kew [:jfkthame]]

The presence of this table can make Core Text font operations really expensive, so if rendering OT-SVG is preffed off, we should drop it entirely.

Comment 1

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1796648 - Drop any SVG table from downloaded fonts if OpenType-SVG rendering is disabled. r=#gfx-reviewers

This makes e.g. https://nabla.typearture.com/ perform VASTLY better on macOS if OT-SVG is preffed off;
without it, we get bogged down in Core Text internally parsing all the SVG when all we want are the
TrueType outlines.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/d1dd198481d0
Drop any SVG table from downloaded fonts if OpenType-SVG rendering is disabled. r=gfx-reviewers,lsalzman

Comment 3

[Natalia Csoregi [:nataliaCs]]

backed out for causing reftest failures on svg-glyph-basic.svg

• backout: https://hg.mozilla.org/integration/autoland/rev/09e22ea3939a17f19a768c99bd3bd569a2cf255f
• push: https://treeherder.mozilla.org/jobs?repo=autoland&group_state=expanded&selectedTaskRun=dvWnR2GtT_C8PZ69UUa1lg.0&revision=d1dd198481d0f0b09a7dd3b36578c5ad083b8eca
• push where perma failures were spotted: https://treeherder.mozilla.org/jobs?repo=autoland&group_state=expanded&selectedTaskRun=DXZiE9RRRiOIUD4mDFlCaQ.0&revision=6ad89191af5500503dd6437c0ad43ee03bc38a19&searchStr=reftest
• failure log: https://treeherder.mozilla.org/logviewer?job_id=394570995&repo=autoland&lineNumber=15575

[task 2022-10-27T16:44:08.461Z] 16:44:08     INFO - REFTEST TEST-START | layout/reftests/text-svgglyphs/svg-glyph-basic.svg == layout/reftests/text-svgglyphs/svg-glyph-basic-ref.svg
[task 2022-10-27T16:44:08.467Z] 16:44:08     INFO - REFTEST INFO | RESTORE PREFERENCE pref(gfx.font_rendering.opentype_svg.enabled,true)
[task 2022-10-27T16:44:08.469Z] 16:44:08     INFO - REFTEST TEST-LOAD | file:///builds/worker/workspace/build/tests/reftest/tests/layout/reftests/text-svgglyphs/svg-glyph-basic.svg | 1 / 29 (3%)
[task 2022-10-27T16:44:08.972Z] 16:44:08     INFO - REFTEST TEST-LOAD | file:///builds/worker/workspace/build/tests/reftest/tests/layout/reftests/text-svgglyphs/svg-glyph-basic-ref.svg | 1 / 29 (3%)
[task 2022-10-27T16:44:09.105Z] 16:44:09     INFO - REFTEST INFO | REFTEST fuzzy test (0, 0) <= (255, 29726) <= (1, 200)
[task 2022-10-27T16:44:09.367Z] 16:44:09     INFO - REFTEST TEST-UNEXPECTED-FAIL | layout/reftests/text-svgglyphs/svg-glyph-basic.svg == layout/reftests/text-svgglyphs/svg-glyph-basic-ref.svg | image comparison, max difference: 255, number of differing pixels: 29726

Comment 4

[Jonathan Kew [:jfkthame]]

Ugh, I think what's happening here is that we first run a test with the pref disabled, and this causes the webfont resource to be cached without its SVG table; then the following tests use that cached resource, and fail.

Maybe we should flush the webfont cache when the pref changes. But in practice it's probably not really important. For reftest purposes, I think we can just defeat the caching by adding a query parameter to the font URL. I'll run that through try to check.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/8dfc0c57e6cb
Drop any SVG table from downloaded fonts if OpenType-SVG rendering is disabled. r=gfx-reviewers,lsalzman

Comment 6

[Cristian Tuns]

https://hg.mozilla.org/mozilla-central/rev/8dfc0c57e6cb