124686 - nsRegionWin::SetTo should use SetRectRgn

Status: RESOLVED FIXED

(Core Graveyard :: GFX, defect)

Description

[Daniel Bratell]

In nsRegionWin::SetTo we destroy the old region and creates a new one. It would
be faster to just set the existing region to a new position with SetRectRgn.
That would save us a DeleteObject and I bet SetRectRgn is much faster than the
CreateRectRgn we use right now and also it would save a couple of byte of code size.

Right now nsRegionWin::SetTo is 7% of the problematic DHTML page in bug 124178
but that extremely high percentage is probably just because it's called too
often. I think.

Comment 1

[Daniel Bratell]

Attachment: Replace DeleteObject/CreateRectRgn with SetRectRgn

Here is a patch. I fixed Init to also don't delete/create when it can as well
just set the region. Reviews? Kevin?

Comment 2

[Daniel Bratell]

A SetRectRgn is ~2us. A CreateRectRgn was ~6us.

Comment 3

[Kevin McCluskey (gone)]

Comment on attachment 68772 [details] [diff] [review]
Replace DeleteObject/CreateRectRgn with SetRectRgn

r=[e-mail].

Comment 4

[Kevin McCluskey (gone)]

Rod can you take a look at Daniel's patch?

Comment 5

[Marc Attinasi]

Comment on attachment 68772 [details] [diff] [review]
Replace DeleteObject/CreateRectRgn with SetRectRgn

sr=attinasi.  Please indicate how this was tested - I am assuming it was tested
:)

Comment 6

[Daniel Bratell]

I've been running with it for a week now and I'm still alive. :-)
I've also stepped through the code and the same things happens now as before.

Taking for checkin.

Comment 7

[Daniel Bratell]

Fix checked in.