517092 - Diagonal scrolling around scaled images slow

Status: RESOLVED FIXED

(Core :: Graphics, defect)

Description

[Glenn Maynard]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.2; en-US; rv:1.9.1.3) Gecko/20090824 Firefox/3.5.3 (.NET CLR 3.5.30729)

When a large image is scaled, scrolling diagonally is very slow.


Reproducible: Always

Steps to Reproduce:
1. Open a large, scaled image: http://zewt.org/~glenn/scaled-image.html
2. Scroll with the scrollbars.  Scrolling is smooth.
3. Middle-click on the document, and smooth scroll vertically.  Scrolling is smooth.
3. Middle-click on the document, and scroll diagonally.  Scrolling is slow and extensive redraw is visible.




Related: bug 246393, bug 443264.  I think both of those are fixed; diagonal scrolling an image at 1:1 is just as fast for me as scrolling on one axis.

I think it's just dropping out of the fast path when scaling and diagonal scrolling are combined.

Comment 1

[Ria Klaassen (not reading all bugmail)]

Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1.4pre) Gecko/20090915 Shiretoko/3.5.4pre

Vertical scrolling takes 1 second and diagonally scrolling 2 seconds.

Comment 2

[Glenn Maynard]

Still happens in 3.6.3.

Comment 3

[Glenn Maynard]

Not that anybody seems to be listening, but closing this since this seems to be fixed in FF4.