116350 - Invalidates should not leak outside of widgets on Mac

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Simon Fraser [no longer active]]

On Mac, calling nsWindow::Invalidate can invalidate an area that is outside the 
widget's visible region, thus causing excess drawing. This is visible (in a build 
with double buffering off) in viewer demo 9, if you scroll frame 3 so that the 
animated images partially underlay the lower 2 frames.

You'd think that, since we maintain an 'mVisRegion' for each nsWindow, it would 
be easy to intersect the invalidate with this. But if you try this, you'll see 
problems with frameset drawing. These happen because the layout code sets the 
size of child frames before their parent frames, so that when we first invalidate 
child nsWindows (which have their final size, but a zero size parent), they think 
that their mVisRegion is empty, and fail to invalidate.

This bug is probably yet another manifestation of the emulated nature of widgets 
on the Mac, which results in an inability to target updates at specific widgets.

Comment 1

[Simon Fraser [no longer active]]

Taking

Comment 2

[Simon Fraser [no longer active]]

I checked with QuartzDebug; this is no longer an issue.