688584 - re-enable hinting on mobile

Status: RESOLVED WONTFIX

(Core :: Graphics, defect)

Description

[Andreas Gal :gal]

I can't see a performance win from disabling hinting on mobile. Re-enabling it.

Comment 1

[Andreas Gal :gal]

Attachment: patch

Comment 2

[Andreas Gal :gal]

Comment on attachment 561856 [details] [diff] [review]
patch

Stuart disabled this supposedly, so asking him for review.

Comment 3

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

(In reply to Andreas Gal :gal from comment #0)
> I can't see a performance win from disabling hinting on mobile. Re-enabling
> it.

How did you test this?  On which device(s)?

Comment 4

[Jonathan Kew [:jfkthame]]

I thought the issue with hinting on mobile was not so much a concern about performance, as that Fennec wants to be able to zoom the text without affecting layout, but hinting can modify glyph metrics and therefore potentially disturbs layout.

Comment 5

[Chris Jones [:cjones] inactive; ni?/f?/r? if you need me]

Quite.

dbaron, how does this fit into your text-reflow work?  Should we block hinting on that?

Comment 6

[Andreas Gal :gal]

jkew, as far as I can tell we are already reflowing. are we concerned that words switch lines as you zoom in?

Comment 7

[Stuart Parmenter]

This will break text rendering on mobile.

Comment 8

[Stuart Parmenter]

Right now, mobile measures text at one size but potentially renders it at a different size.  We do that without re-measuring the text for performance reasons.  Because of this, and because we did not want text to move as you zoom, we must either disable hinting, or figure out how to leave text hinting on but account for it when we render text (we'd need to probably do line-level limiting to ensure that a line can fit inside a given box? -- not totally clear what the right thing to do visually would be).

Anyways, if you turn hinting back on, text will start to render on top of itself or with weird spacing artifacts and will generally be bad.

If you *always* remeasure text (because we do a full reflow on zoom, or something similar) then you could enable hinting.  Even when we reflow sometimes, it isn't clear that we would want to always.  Probably safer to leave this off.

Comment 9

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

The bug assignee didn't login in Bugzilla in the last 7 months.
:bhood, could you have a look please?
For more information, please visit auto_nag documentation.

Comment 10

[Bob Hood [:bhood]]

Jamie, I know this is QUITE a stretch, but any chance you can verify that this is (or isn't) still valid? If it's no longer valid, please feel free to close it.

Comment 11

[Jamie Nicol [:jnicol]]

Seems like we don't want to do this for correctness reasons with non-reflowing zoom