2089278 - Fit unspaced text while accumulating glyph metrics

Status: ASSIGNED

(Core :: Layout: Text and Fonts, enhancement)

Description

[Mayank Bansal]

sp3 : https://perf.compare/compare-results?baseRev=2f484e970286be4eff3ac22fe436327107c580f8&baseRepo=try&newRev=b8d7218efab2bd39181f4a88b5a6ba68511b47a4&newRepo=try&framework=1&framework=13&filter_status=none%2Cimprovement%2Cregression&sort=median-diff%7Cdesc&initialized=1
5% on tiptap, 0.3% overall. But it also regresses other tests by 0.1%-0.2%

Try: https://treeherder.mozilla.org/jobs?repo=try&revision=0743458627cfb6bd7ddf7666915d67befde6e6b3

Comment 1

[Mayank Bansal]

Attachment: Bug 2089278 - Fit unspaced text while accumulating glyph metrics

Fit a single font run during the existing glyph measurement pass when
spacing and hyphenation are absent and loose ink bounds are requested.
Keep call-local snapshots of glyph-dependent metrics at accepted breaks,
including emergency wrapping, break-spaces and trimmable whitespace.
Finalize the selected prefix through the existing font metrics, RTL,
synthetic-oblique, baseline and platform-padding code.

Retain the general path for multiple font runs, spacing, hyphenation,
tight bounds and partial ligatures. Specialize ordinary measurement so
callers that do not fit text have no per-glyph fitting checks. Also batch
simple unbreakable glyph spans in the eligible general fitting path.

No persistent cache or text-run invalidation machinery is introduced.

Comment 2

[Mayank Bansal]

Attachment: Bug 2089278 - Batch simple glyph spans in general text fitting.

Sum simple non-space glyphs without break flags in a compact loop when
spacing, hyphenation and additional wrapping opportunities are absent.
Retain ligature boundaries and reset trailing-whitespace state after a
non-space span. Skip buffer refills when neither spacing nor hyphenation
data is needed.

This optimization is independent of fused fitting and glyph measurement.

Comment 3

[Mayank Bansal]

sp3 for D339767 only: https://perf.compare/compare-results?baseRev=2f484e970286be4eff3ac22fe436327107c580f8&baseRepo=try&newRev=61702c215379c61c1302d050c19dead2190e3d03&newRepo=try&framework=1&framework=13&filter_status=none%2Cimprovement%2Cregression&sort=median-diff%7Cdesc&initialized=1

SP3 for D339778 only: https://perf.compare/compare-results?baseRev=2f484e970286be4eff3ac22fe436327107c580f8&baseRepo=try&newRev=1b7524d4df90656663f8fe588946477a47e30b57&newRepo=try&framework=1&framework=13&sort=median-diff%7Cdesc&initialized=1

So D339767 has almost all of the perf improvement. So D339778 is optional I guess.

Comment 4

[Phabricator Automation]

Comment on attachment 9674568 [details]
Bug 2089278 - Batch simple glyph spans in general text fitting.

Revision D339778 was moved to bug 2090465. Setting attachment 9674568 [details] to obsolete.

Comment 5

[Mayank Bansal]

Attachment: WIP: Bug 2089278 - Avoid unnecessary ligature fitting fallback

Comment 6

[Mayank Bansal]

Attachment: WIP: Bug 2089278 - Stop measuring simple glyphs after overflow

Comment 7

[Mayank Bansal]

Attachment: WIP: Bug 2089278 - Share line break classification

Comment 8

[Mayank Bansal]

Attachment: WIP: Bug 2089278 - Simplify contained glyph bounds accumulation

Comment 9

[Mayank Bansal]

try: https://treeherder.mozilla.org/jobs?repo=try&revision=c4a379cf25c84e46f3e15b8a5ae19d8dc63f6df9

Comment 10

[Mayank Bansal]

Attachment: Bug 2089278 - Fit unspaced text while accumulating glyph metrics. r=#gfx-reviewers

Fit a single font run during the existing glyph measurement pass when
spacing and hyphenation are absent and loose ink bounds are requested.
Keep call-local snapshots of glyph-dependent metrics at accepted breaks,
including emergency wrapping, break-spaces and trimmable whitespace.
Finalize the selected prefix through the existing font metrics, RTL,
synthetic-oblique, baseline and platform-padding code.

Retain the general path for multiple font runs, spacing, hyphenation,
tight bounds and partial ligatures. Specialize ordinary measurement so
callers that do not fit text have no per-glyph fitting checks. Also batch
simple unbreakable glyph spans in the eligible general fitting path.

No persistent cache or text-run invalidation machinery is introduced.

Comment 11

[Mayank Bansal]

SP3 : https://perf.compare/compare-results?baseRev=c64da9d5d459cc297e4d4fda6d41253a38a75a93&baseRepo=try&newRev=6d4549b233dd34167e94fb5ea165be89776cda15&newRepo=try&framework=1&framework=13&sort=median-diff%7Cdesc&initialized=1
Try: https://treeherder.mozilla.org/jobs?repo=try&landoInstance=lando-prod-2025&landoCommitID=116704

The interesting thing is that this is the same patch as in comment 0. And the perf results are quite different for Windows. Make what you will of this. But atleast the patch is effective.