986580 - Enable harfbuzz support in freetype (2.5.3+)

Status: NEW

(Core :: Graphics: Text, enhancement)

Description

[Michael Wu [:mwu]]

Attachment: Enable harfbuzz support in freetype

I figured out how to turn on harfbuzz support, as requested in bug 985803 comment 4 , but I have no idea if it's doing anything good. Jonathan, do you want to try this and see if this seems to give reasonable results? At the very least, it builds and continues to render text reasonably.

Comment 1

[Michael Wu [:mwu]]

This patch will require the patch from 985806 to be applied first.

Comment 2

[Michael Wu [:mwu]]

I'll also be requesting review from a build peer for this changes, but I figure we should find out if it's doing something reasonable first.

Comment 3

[Jonathan Kew [:jfkthame]]

Sorry I haven't gotten to this yet. In theory, enabling harfbuzz support should result in more consistent glyph hinting for things like glyph variants that are only accessed via OpenType features, not as default Latin-script glyphs. But finding/creating examples where the difference is visible may take a bit of digging around.

Comment 4

[Ryan VanderMeulen [:RyanVM]]

Is this something we'd still want to do?

Comment 5

[Jonathan Kew [:jfkthame]]

As I understand it, this would primarily (only?) affect Android builds, as that's where we use the in-tree freetype; Linux builds typically use system freetype (so they'll be affected by how the system lib is built, but that's out of our hands), and Windows and macOS don't use it at all.

Not sure what the current situation is with regard to hinting settings on Android; it's possible we're rendering without hinting anyhow, in order to ensure linear scaling for pinch-zoom, in which case I don't know if the harfbuzz support here (which is used to assist the FT autohinter) would actually come into play or not.

Short answer: I'm unsure how much value - if any - this would offer us; OTOH, it shouldn't have any ill effects, so no harm in trying.

Comment 6

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

The bug assignee didn't login in Bugzilla in the last 7 months.
:lsalzman, could you have a look please?
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