Some Eclipse Foundation services are deprecated, or will be soon. Please ensure you've read this important communication.
Bug 370313 - [Canvas] Tweak canvas performance in IE7/8
Summary: [Canvas] Tweak canvas performance in IE7/8
Status: CLOSED WONTFIX
Alias: None
Product: RAP
Classification: RT
Component: RWT (show other bugs)
Version: 1.5   Edit
Hardware: All All
: P3 enhancement (vote)
Target Milestone: ---   Edit
Assignee: Project Inbox CLA
QA Contact:
URL:
Whiteboard:
Keywords:
Depends on:
Blocks: 361615
  Show dependency tree
 
Reported: 2012-02-01 05:56 EST by Tim Buschtoens CLA
Modified: 2014-08-07 04:57 EDT (History)
0 users

See Also:

Attachments
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Tim Buschtoens CLA 2012-02-01 05:56:14 EST 
Canvas in IE7/8 is using VML to draw, which gets very slow when the number of shapes increases. To improve performance, the follwing could be done:

* Remove shapes that are completely obscured. To keep this simple, only do this when the entire canvas is painted over with a rectangle. More complex versions are probably not worth the effort.

* Try merging shapes that have same properties. Doable at least with shapes that arent filled and could decrease the number of shapes considerably in some cases.

* Pool a limited number of shape objects outside of DOM. This might or might not work.

Fixing this would also be useful for client-scripted painting.
Comment 1 Tim Buschtoens CLA 2012-02-01 08:33:06 EST 
An additional or alternative solution would be to support flashcanvas http://flashcanvas.net. It has a MIT license.

Also, the text-layer of canvas should not be created unless its needed. For most browser its also not really necessary anymore.
Comment 2 Ivan Furnadjiev CLA 2014-08-07 04:57:51 EDT 
The IE7/8 support is discontinued in RAP 3.0. Close as WONTFIX.