453819 - Performance regression in firefox 3

Status: RESOLVED DUPLICATE of bug 372039

(Firefox :: General, defect)

Description

[HJ]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1

When we have in a html page a large background image (example 1280x1024 image) and we resize it to fit to a small display (640x480) the display of the html page becomes very slow.
The same test with Firefox 2 doesn't show any performance problems.
Workaround: resize natively the background image.

Reproducible: Always

Steps to Reproduce:
1.
2.
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Comment 1

[Matthias Versen [:Matti]]

Such a general description isn't enough.
Either attach a testcase or point to a URL.

I assume that you mean a fixed background and you mean bug 372039
(easy to find with search keywords "background slow"

marking as dupe, please reopen if you don't mean a fixed background.

Comment 2

[HJ]

Attachment: An example to reproduce the problem

The html file contains an 1024x768 image "langue.png" (img tag).
When we load this html file on the test machine, the display becomes very slow (CPU usage ~100%). Here are the characteristics of the test machine :
  - Windows XP SP2.
  - Intel P4 2GHz
  - 512Mb RAM
  - 640x480 display
Now we change the image to langue2.png (which is the same image natively resized to 640x480) performance is correct.

Comment 3

[HJ]

I am not sure that this is the same problem with bug id 337420...
Here the image is not placed with background-image css property.