630891 - nsSubDocumentFrames are always repainted when they move

Status: RESOLVED FIXED

(Core :: Web Painting, defect)

Description

[Patrick Walton (:pcwalton)]

nsSubDocumentFrames seem to always be repainted in full when they move:

http://mxr.mozilla.org/mozilla-central/source/layout/generic/nsSubDocumentFrame.cpp#677

This means that animating them via -moz-transform can never get the benefit of retained layers.

Do we need this anymore? The comment seems to indicate otherwise...

Comment 1

[Timothy Nikkel (:tnikkel)]

Looks like that code originates from bug 124507. Where it seems it was extra debugging code accidentally checked in, the mistake was noticed, and a backout patch was made, but the backout patch never got checked in.

Comment 2

[Patrick Walton (:pcwalton)]

Removed and testing on try.

Comment 3

[Robert O'Callahan (:roc) (email my personal email if necessary)]

(In reply to comment #0)
> nsSubDocumentFrames seem to always be repainted in full when they move:

ITYM "even when they DON'T move"

Great catch, by the way.

Comment 4

[Patrick Walton (:pcwalton)]

(In reply to comment #3)
> (In reply to comment #0)
> > nsSubDocumentFrames seem to always be repainted in full when they move:
> 
> ITYM "even when they DON'T move"
> 
> Great catch, by the way.

Well, I meant when they do move, under -moz-transform. Animating e.g. an iframe via a transition on -moz-transform does move the iframe, but it shouldn't repaint with retained layers AIUI.

Comment 5

[Patrick Walton (:pcwalton)]

Attachment: Proposed patch.

Here's a patch. Seems to work on try.

Comment 6

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Comment on attachment 509225 [details] [diff] [review]
Proposed patch.

We'd better get this in for a beta.

Comment 7

[Patrick Walton (:pcwalton)]

http://hg.mozilla.org/mozilla-central/rev/b0325a41a167