974607 - Don't use subpixel aa w/D2D on transparent surfaces if possible

Status: REOPENED

(Core :: Graphics, defect)

Description

[Jeff Muizelaar [:jrmuizel]]

The D2D path for this is slow and we're getting hurt a lot on the australis customize transition.

We have a couple of different options here:
1. Disable subpixel-aa on transparent surfaces in chrome.
2. Disable subpixel-aa on transparent surfaces everywhere.

I think it's ok to not have subpixel-aa on tab titles, but it would be nice if we can still have subpixel-aa on the url bar text. I'm not exactly sure what would need to happen for that to be possible.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

We may, in fact, just be able to do better.

Comment 2

[Jeff Muizelaar [:jrmuizel]]

Attachment: Something like this

Comment 3

[Mike Conley (:mconley) (:⚙️)]

The advantage of doing something like this is pretty substantial, according to the CART test results in bug 974407.

I'm marking this as a P2 Australis bug - I do believe we want this.

Comment 4

[Mike Conley (:mconley) (:⚙️)]

Is this something that should go through review now, or is it still a WIP patch?

Comment 5

[Jeff Muizelaar [:jrmuizel]]

Still a WIP. There are bugs that might not be easy to solve.

Comment 6

[Justin Dolske [:Dolske]]

Do we still want to call this P2? Sounded like the there were bigger wins from the about:customizing preloading, and that this was small peanuts?

Comment 7

[Justin Dolske [:Dolske]]

(Calling this Jeff's since he's got the WIP patch)

Comment 8

[Mike Conley (:mconley) (:⚙️)]

(In reply to Justin Dolske [:Dolske] from comment #6)
> Do we still want to call this P2? Sounded like the there were bigger wins
> from the about:customizing preloading, and that this was small peanuts?

I think so? According to [1], approximately 50% of our Windows 7 users have d2d layer acceleration enabled, meaning that about half of our Windows users will experience the slowdown from the subpixel AA.

It's a pretty substantial change, according to the compare-talos I did in bug 974407[2].

So, based on user exposure and potential payoff, I think we should try to chase this one down.

[1]: http://people.mozilla.org/~bjacob/gfx_features_stats/#win7
[2]: http://compare-talos.mattn.ca/?oldRevs=fa48d6ebc486&newRev=306fd5b6afb6&server=graphs.mozilla.org&submit=true

Comment 9

[Mike Conley (:mconley) (:⚙️)]

So it turns out I can toggle subpixel AA by setting opacity of 0.99 on text.

I'm going to whip up a patch to do that during the transition to see what that buys us.

Comment 10

[Mike Conley (:mconley) (:⚙️)]

I've pushed a POC patch to try that uses CSS to disable subpixel AA during the customize mode transition. It's a pretty big hammer - I basically just set opacity to 0.99 on all labels during the transition.

Baseline: https://tbpl.mozilla.org/?tree=Try&rev=21e77b801df3
Patch: https://tbpl.mozilla.org/?tree=Try&rev=7660be8d3aa9
Compare talos: http://compare-talos.mattn.ca/?oldRevs=21e77b801df3&newRev=7660be8d3aa9&server=graphs.mozilla.org&submit=true

Comment 11

[Mike Conley (:mconley) (:⚙️)]

jrmuizel:

mattwoodrow wants to know what the problems are remaining with this patch, since he says it looks sane.

Comment 12

[Mike Conley (:mconley) (:⚙️)]

Apparently, the opacity trick was a bit silly since it seems to cost more to pull that trick than to do the subpixel AA itself.

mattwoodrow suggested applying transform:perspective(1px) on the text instead, so I'm trying that next.

Baseline: https://tbpl.mozilla.org/?tree=Try&rev=21e77b801df3
Patch: https://tbpl.mozilla.org/?tree=Try&rev=b5d485143452
Compare talos: http://compare-talos.mattn.ca/?oldRevs=21e77b801df3&newRev=b5d485143452&server=graphs.mozilla.org&submit=true

Comment 13

[Dão Gottwald [:dao]]

(In reply to Jeff Muizelaar [:jrmuizel] from comment #0)
> I think it's ok to not have subpixel-aa on tab titles

Why do you think that's ok? Sounds like a significant regression to me... except for Aero Glass where we already get grayscale AA, unfortunately. This is primary UI that users see all the time, with text that users read all the time. We shouldn't dismiss this as less important than the customize transition.

Comment 14

[Jeff Muizelaar [:jrmuizel]]

(In reply to Dão Gottwald [:dao] from comment #13)
> (In reply to Jeff Muizelaar [:jrmuizel] from comment #0)
> > I think it's ok to not have subpixel-aa on tab titles
> 
> Why do you think that's ok? Sounds like a significant regression to me...
> except for Aero Glass where we already get grayscale AA, unfortunately. This
> is primary UI that users see all the time, with text that users read all the
> time. We shouldn't dismiss this as less important than the customize
> transition.

I was only talking about Aero Glass.

Comment 15

[Dão Gottwald [:dao]]

But we already get grayscale AA on Glass. What would this bug change?

Comment 16

[Jeff Muizelaar [:jrmuizel]]

(In reply to Dão Gottwald [:dao] from comment #15)
> But we already get grayscale AA on Glass. What would this bug change?

That is a little unclear at this point.

Comment 17

[Mike Conley (:mconley) (:⚙️)]

Wow - a pretty substantial win if I use mattwoodrow's transform:perspective(1px) hack. Especially on Windows 8.

Given our time constraints, I think that's the route I'm going to pursue.

Comment 18

[Mike Conley (:mconley) (:⚙️)]

CART results on OS X and Linux don't show the same improvement (in fact, CART results come in worse in some cases):

http://compare-talos.mattn.ca/?oldRevs=71efe1f6d4a7&newRev=fdc2ed44e85d&server=graphs.mozilla.org&submit=true

I think this will be a Windows-only improvement.

Comment 19

[Mike Conley (:mconley) (:⚙️)]

Also, I'm going to extract the work I'm doing to disable subpixel AA during the transition into a separate bug. It's possible that jrmuizel may want to follow-up on some of this for non-Australis performance things, but I don't think it's a blocker for Australis anymore.

I've filed bug 977796 for the split out work. jrmuizel, if you don't feel this is still worth pursuing for other reasons, feel free to close this bug.

Comment 20

[Tim Nguyen :ntim]

If transparent surfaces cause this, I'd suggest removing them as much as possible from the Browser UI.
For example, the subviews has a rgba(255,255,255,0.97) background, which could be changed to white.

Comment 21

[Justin Dolske [:Dolske]]

P- per comment 19 (still showing up in the tracker through the other bug).

Comment 22

[Jeff Muizelaar [:jrmuizel]]

Attachment: subaa

I'd like to try landing this to see if it causes any bugs for anyone.

Comment 23

[BMO Automation]

Per policy at https://wiki.mozilla.org/Bug_Triage/Projects/Bug_Handling/Bug_Husbandry#Inactive_Bugs. If this bug is not an enhancement request or a bug not present in a supported release of Firefox, then it may be reopened.