1403302 - Eliminate dependency on cairo fonts for getting glyph metrics

Status: RESOLVED FIXED

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

Description

[Jonathan Kew [:jfkthame]]

We currently rely on cairo font APIs to get glyph extents, even when we aren't actually rendering via cairo any more. This seems inefficient (as it requires us to set up cairo fonts just for this purpose), and will make the implementation of Variation Fonts harder than it should be (because we'll need to plumb variations through the cairo font code in addition to moz2d/skia/webrender/whatever).

We should just get rid of this dependency and figure out how to get glyph metrics/extents via the same font backend as we're using to render.

Comment 1

[Jonathan Kew [:jfkthame]]

Attachment: patch 1 - Add missing return statement to ScaledFontBase::GetGlyphDesignMetrics, so that its cairo-based code path actually works

Comment 2

[Jonathan Kew [:jfkthame]]

Attachment: patch 2 - Fix mixed-up glyph bounding box coordinates in ScaledFontDWrite::GetGlyphDesignMetrics

Comment 3

[Jonathan Kew [:jfkthame]]

Attachment: patch 3 - Remove direct cairo dependency from gfxTextRun and gfxGlyphExtents

Comment 4

[Bas Schouten (:bas.schouten)]

Comment on attachment 8930248 [details] [diff] [review]
patch 3 - Remove direct cairo dependency from gfxTextRun and gfxGlyphExtents

Review of attachment 8930248 [details] [diff] [review]:
-----------------------------------------------------------------

Stealing review as Jeff is on PTO.

Comment 5

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/mozilla-inbound/rev/cdc8898f59b3
patch 1 - Add missing return statement to ScaledFontBase::GetGlyphDesignMetrics, so that its cairo-based code path actually works. r=bas
https://hg.mozilla.org/integration/mozilla-inbound/rev/ade4ee8e1bfc
patch 2 - Fix mixed-up glyph bounding box coordinates in ScaledFontDWrite::GetGlyphDesignMetrics. r=bas
https://hg.mozilla.org/integration/mozilla-inbound/rev/d4f80c4ba719
patch 3 - Remove direct cairo dependency from gfxTextRun and gfxGlyphExtents. r=bas

Comment 6

[Tiberius Oros[:tiberius_oros]]

https://hg.mozilla.org/mozilla-central/rev/cdc8898f59b3
https://hg.mozilla.org/mozilla-central/rev/ade4ee8e1bfc
https://hg.mozilla.org/mozilla-central/rev/d4f80c4ba719

Comment 7

[Ionuț Goldan [:igoldan]]

Looks like this brought some AWSY improvements:

== Change summary for alert #10719 (as of Thu, 23 Nov 2017 17:40:52 GMT) ==

Improvements:

  4%  Heap Unclassified summary windows7-32 opt      42,427,149.35 -> 40,924,380.53
  3%  Heap Unclassified summary windows10-64 pgo     49,933,293.77 -> 48,426,975.48
  3%  Heap Unclassified summary windows10-64 opt     49,945,868.79 -> 48,541,249.41
  3%  Heap Unclassified summary windows7-32 pgo      42,149,408.59 -> 41,023,741.65

For up to date results, see: https://treeherder.mozilla.org/perf.html#/alerts?id=10719