Open Bug 552499 Opened 14 years ago Updated 2 years ago

text-shadow in pseudo-class :hover very slow

Categories

(Core :: Layout: Text and Fonts, defect)

Product:
Core
Component:
Layout: Text and Fonts
Type:
defect

Tracking

()

Status:
UNCONFIRMED

People

(Reporter: witi83, Unassigned)

References

(
URL
)

Details

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.2) Gecko/20100115 Firefox/3.6
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.1; de; rv:1.9.2) Gecko/20100115 Firefox/3.6

On http://50226.de/ I'm using text-shadow (the title links) in the pseudo-class
:hover with following css: .entry h2 a:hover {text-shadow:0 0 5px #FFF;}

As you can see the hover effect is extremly slow and the load (on a Core 2 Duo
6400, Windows 7 64, 4GB RAM, Firefox 3.6) goes up to 50%.

Other browsers like chromium doesn't show this issue.

Reproducible: Always

Steps to Reproduce:
keep on hovering over the links
Actual Results:  
high load, up to 50% (on a Core 2 Duo 6400, Windows 7 64, 4GB RAM, Firefox 3.6)

Expected Results:  
no or less load.
I don't think it's the text-shadow itself. I think it's that we're invalidating too much and we're also painting some large box-shadows, which are slow.

Michael, does your box-shadow patch help here?
This issue is still present in the current firefox 17 beta.
Are you still able to reproduce? I think this has been fixed.
Flags: needinfo?(witi83)
Yes, the problem still exists. I've uploaded a small page, which should demonstrate the problem: https://dl.dropboxusercontent.com/u/89035831/552499.html

This is the code:
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>Bug 552499</title>
<style type="text/css">a:hover{text-shadow:0 0 10px #000}</style>
</head>
<body>
<h1><a href="">Link1</a></h1>
<h1><a href="">Link2</a></h1>
<h1><a href="">Link3</a></h1>
<h1><a href="">Link4</a></h1>
<h1><a href="">Link5</a></h1>
</body>
</html>

Just keep on hovering of the links. Even in the latest stable version (Firefox 31), you should notice a pretty high load, depending on your CPU. Compared to other browsers like Chrome 38 and IE 11 the hover-effect is still quite slow as well.
Flags: needinfo?(witi83) → needinfo?(nobody)
Your testcase works fine for me.
Flags: needinfo?(nobody)
Severity: normal → S3
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