938754 - Move opacity from Aero Glass Fog into alpha channel of TabsToolbar::before box-shadow colour

Status: RESOLVED FIXED

(Firefox :: Theme, defect)

Description

[Mike Conley (:mconley) (:⚙️)]

On Windows 7, we display a fog behind the tabstrip to make it easier to read the tab labels over the glass. That fog is actually a box-shadow with blur, and is semi-opaque to give it a foggy effect. Think frosted-glass.

According to mattwoodrow, putting the opacity directly on the element (the TabsToolbar::before pseudoelement to be exact), results in us taking a slow-path in layout land. It's much faster if we move the opacity value into the alpha channel of the colour we set the box-shadow.

This should result in a super-easy win for TART, according to mattwoodrow.

Comment 1

[Mike Conley (:mconley) (:⚙️)]

Attachment: Patch v1

Here we go. Try and compare-talos links coming up.

Comment 2

[Mike Conley (:mconley) (:⚙️)]

Both of these builds have bug 934860 backed out.

UX baseline: https://tbpl.mozilla.org/?tree=Try&rev=fd7407dccf60
UX + patch: https://tbpl.mozilla.org/?tree=Try&rev=76a5ab575769

compare-talos: http://compare-talos.mattn.ca/?oldRevs=fd7407dccf60&newRev=76a5ab575769&server=graphs.mozilla.org&submit=true

Comment 3

[Mike Conley (:mconley) (:⚙️)]

Comment on attachment 832526 [details] [diff] [review]
Patch v1

This is a pretty clear win.

Comment 4

[:Gijs (he/him)]

Comment on attachment 832526 [details] [diff] [review]
Patch v1

Review of attachment 832526 [details] [diff] [review]:
-----------------------------------------------------------------

Stealing this review. Ship it!

Comment 5

[Mike Conley (:mconley) (:⚙️)]

Landed in UX as https://hg.mozilla.org/projects/ux/rev/8b514254b168

Comment 6

[Matt Woodrow (:mattwoodrow)]

As discussed with Mike on irc, there's still somewhere else in the UI that is doing this, though it gets invalidated much less often.

I filed bug 939607 for handling this efficiently within layout.

Comment 7

[:Gijs (he/him)]

https://hg.mozilla.org/mozilla-central/rev/8b514254b168