72893 - 15% of all calls to nsIViewManager::MoveViewTo only move the view 1 pixel

Status: RESOLVED WORKSFORME

(Core :: Layout, defect)

Description

[Kevin McCluskey (gone)]

For some reason a large percentage (15%) of all of the calls to move a view only
move it a single pixel. Since it is a single pixel it leads me believe that the
view is being asked to be moved as result of twips->pixel rounding error. This
is a performance issue because moving the view will cause the view's old rect
and new rect to be invalidated, resulting in unnessary repaints.

Comment 1

[Kevin McCluskey (gone)]

Marc, could this be related to the deflate logic for borders in frames?

Comment 2

[Markus Hübner]

Is the bug summary still valid (15%) ?

Comment 3

[Boris Zbarsky [:bzbarsky]]

Kevin, is this still an issue?

Comment 4

[Scott Johnson (:jwir3)]

With the following setup:

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0a1) Gecko/20111113 Firefox/11.0a1

I added instrumentation to nsViewManager::MoveViewTo to determine what percentage of these calls are actually 1 pixel moves. With a 5-10 minute browsing test, a variety of tabs, and close/reopens/resizes, etc., 0% of these were 1 pixel moves. 

I'm closing this bug as WFM, but please accept my apologies if it is still a relevant issue. Please reopen if this is the case.