99153 - Extremely slow performance with big png backgrounds

Status: VERIFIED DUPLICATE of bug 64401

(Core :: Graphics: ImageLib, defect)

Description

[Aleksander Adamowski]

Build ID: 2001091003

When displaying a page where a 32-bit png image is used as a background, Mozilla
eats lots of cpu power and gets semi-responsive.
BTW this doesn't seem to be a dup of bug 64188 because I cannot reproduce 64188.

Comment 1

[Aleksander Adamowski]

Attachment: zipped testcase from office.altkom.com.pl

Comment 2

[Aleksander Adamowski]

To test aformentioned semi-responsiveness, try to select portions of text on the
page.
BTW, this bug's URL is the same thing as the zipped testcase. The URL may be
more convenient for your testing pleasure :-)

Comment 3

[Terri Preston]

I still see high CPU usage with these images win XP build 2001110803

Comment 4

[Brian Rogers]

The problem is that the extra 8 bits in the 32-bit image is an alpha channel, so
it has to be composited with what's behind the image.
This is a dup of bug 64401.  Very same image, in fact.

Comment 5

[Dimitrios]

Wfm on 2002022308, Win98. Very low cpu usage on K6-III/400, 192MB ram.
Aleksander, are you still seeing this?

Comment 6

[Brian Rogers]

Build 2002022203 on Win2k, I'm still seeing this.
Try selecting text on the 32-bit PNG, and moving the mouse rapidly.

Comment 7

[Aleksander Adamowski]

I'm still seeing this too on Win2K. Trunk build 2002022308.
When I'm drag-selecting the text, CPU usage jumps to 100%.
When I stop, CPU usage drops to normal level.

Comment 8

[Dimitrios]

Now I see what you mean: cpu usage (in Win2K) jumps to 100% when I select text,
for the 32bit png only. But this peak is so short in duration that I would never
say that Mozilla is semi-responsive (as originally described). Considering the
relatively low end machine I use, I think (my opinion) that this bug should be
resolved as wfm. There are far more significant bugs on ImageLib than this one.

Comment 9

[Brian Rogers]

I would still consider the selection performance unacceptable.  And it's even
worse with scrolling.
But this is really a dup of bug 64401.

Comment 10

[Dimitrios]

I think so. Let's dupe it. The other bug also has a better (slightly more heavy)
testcase.

*** This bug has been marked as a duplicate of 64401 ***

Comment 11

[Terri Preston]

Verified Duplicate