1071367 - Composition bounds for root content scroll frame in OS X ignores height of chrome

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Kartikaya Gupta (email:[e-mail])]

Start nightly, set layers.async-pan-zoom.enabled and layers.draw-borders to true from about:config, and load a scrollable page (e.g. http://planet.mozilla.org/). Scroll down and observe that there is a purple border that starts at the top of the chrome and stops 79 pixels from the bottom of the window (79 pixels being the height of the chrome for me). This purple border is the composition bounds of the scrollable content document, but it has a top-left of (0,0) instead of (0,79).

This also means that using the two-finger trackpad scroll gesture doesn't work while the mouse cursor is in the bottom 79 pixels of the content (outside the purple rect).

Comment 1

[Kartikaya Gupta (email:[e-mail])]

This is a regression from bug 1043644 part 1, which switched to using the content viewer bounds instead of the frame bounds to fix behaviour on metro. Switching back to the frame bounds fixes the problem. It also fixes the problem where, with APZC enabled, the displayport is offset from tile boundaries by the height of the chrome.

Comment 2

[Kartikaya Gupta (email:[e-mail])]

Attachment: Thing that fixes the bug

Comment 3

[Kartikaya Gupta (email:[e-mail])]

Attachment: Real patch

Comment 4

[Timothy Nikkel (:tnikkel)]

Comment on attachment 8493806 [details] [diff] [review]
Real patch

Yeah, that makes sense. Wouldn't expect content viewer bounds to have the right offset.

Comment 5

[Wes Kocher (:KWierso) (Not reading bugmail; email directly if needed)]

https://hg.mozilla.org/mozilla-central/rev/8abfd1252969