1261062 - When clamping the displayport margins to the max texture size, the margin is distributed unevenly

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

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

The code added in bug 1135907 prevented the displayport from expanding beyond the maximum texture size. However when doing so it calculated a "budget" and then spent as much of the budget as possible on the top/left margin, using the rest for the bottom/right margin. If this code is hit, it can result in the displayport being "skewed" towards the top/left of the visible area, and so checkerboarding occurs more easily when scrolling down/right. This happened in bug 1258051 for example.

Comment 1

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

Attachment: Patch

Comment 2

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

Attachment: Patch for landing

Update r= so patch is ready for landing, to go into landing queue.

Comment 3

[Pulsebot]

https://hg.mozilla.org/integration/mozilla-inbound/rev/d9d29cea3572

Comment 4

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

https://hg.mozilla.org/mozilla-central/rev/d9d29cea3572

Comment 5

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

Comment on attachment 8736889 [details] [diff] [review]
Patch for landing

Approval Request Comment
[Feature/regressing bug #]: APZ
[User impact if declined]: bug 1258051 is one example - if the user's system has smaller max texture sizes they can run into checkerboarding more frequently. Not many users will run into this problem.
[Describe test coverage new/current, TreeHerder]: tested by reporter of bug 1258051, no automated coverage for this particular bug
[Risks and why]: low risk, the codepath in question is not hit very often. low-impact fix and low risk.
[String/UUID change made/needed]: none

Comment 6

[Ritu Kothari (:ritu) (Inactive, please n-i to RyanVM, jcristau, or pascal)]

Comment on attachment 8736889 [details] [diff] [review]
Patch for landing

Fix was verified in bug 1258051, Aurora47+

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/releases/mozilla-aurora/rev/b8a888b7858a