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Bug 361408

Summary: Clipping Support for GraphicContext used in Canvas
Product: [RT] RAP Reporter: Avrajit Chatterjee <avrajit.chatterjee>
Component: RWTAssignee: Project Inbox <rap-inbox>
Status: CLOSED WONTFIX QA Contact:
Severity: enhancement    
Priority: P3 CC: chenxihui1981, tbuschto
Version: unspecified   
Target Milestone: ---   
Hardware: All   
OS: All   
Whiteboard:

Description Avrajit Chatterjee CLA 2011-10-19 10:29:47 EDT 
Build Identifier: 1.5 M2

Currently RAP does not support the setting of clipping in GC. This causes an issue in the usage of some great SWT custom components built on Canvas container. The total canvas need to be redrawn again and again even if a small region needs to be redrawn. This hampers the performance of the web applications when no. of items in the Canvas to be drawn are grows.

Reproducible: Always

Steps to Reproduce:
1.Draw any to 2 components in a Canvas
2.Write some to redraw one component on some event.
3.You will find the other component is not visible in the browser.
For that one needs to redraw the whole canvas again. This is because GC does not support clipping in RAP.
Comment 1 Tim Buschtoens CLA 2011-10-20 05:37:13 EDT 
Here's the problem: Clipping could propably be implemented in RAP. However, the performance would be horrible in IE (at least 7/8 where there is no HTML-Canvas). I had other ideas to allow partial redrawing in RAP, however these would not be compatible with SWT, so no single sourcing. See Bug 360978 (especially the first comment) for technical details. Any suggestions how to solve this issue are welcome.
Comment 2 Tim Buschtoens CLA 2012-01-20 05:42:59 EST 
Closed because there is no practical way to implement this. We might introduce some alternative for partial redrawing.
Comment 3 Ivan Furnadjiev CLA 2012-07-18 03:44:30 EDT 
*** Bug 381080 has been marked as a duplicate of this bug. ***