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Canvas with overlaid buttons speed problem [message #659739]

Tue, 15 March 2011 12:59

Dominic Hanlan

Messages: 98
Registered: July 2009

Member

Hi,

I have an editor which as its main component has a canvas, I have added a paintlistener to this which draws an image (png) on the background.

So far so good.

As this is a "home page" I have placed buttons in a grid over the canvas. Originally the canvas was just a plain composite, but I want to brand the product with the image.

Now the problem is one of speed, as the screen is displayed, either initially or on resize, the image is resized correctly. The buttons in the forground though take about a half a second each to display!!!.

I have read several snippets about using canvas and painlistener to render the image, but the overlaying buttons are the issue.

I got the idea from another eclipse application I saw, unfortunately this is a commercial product and not open to discussion of implementation.

Any ideas, pointers???

Regards

/Dominic

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Re: Canvas with overlaid buttons speed problem [message #660056 is a reply to message #659739]

Wed, 16 March 2011 17:22

Lakshmi P Shanmugam

Messages: 277
Registered: July 2009
Location: India

Senior Member

This article maybe useful --> http://www.eclipse.org/articles/Article-SWT-graphics/SWT_gra phics.html

Lakshmi P Shanmugam

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Re: Canvas with overlaid buttons speed problem [message #660179 is a reply to message #660056]

Thu, 17 March 2011 09:20

Dominic Hanlan

Messages: 98
Registered: July 2009

Member

Thanks for the link.

The problem is that the code works perfectly, it's just the speed of the button rendering that is the issue. If I have a standard composite as the parent, it's fine, if I have a canvas the speed is incredibly slow for each button to appear?????

Regards

/Dominic

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Re: Canvas with overlaid buttons speed problem [message #661460 is a reply to message #660179]

Thu, 24 March 2011 17:57

Grant Gayed

Messages: 2150
Registered: July 2009

Senior Member

I took
http://dev.eclipse.org/viewcvs/index.cgi/%7Echeckout%7E/org. eclipse.swt.snippets/src/org/eclipse/swt/snippets/Snippet172 .java ,
inserted a Canvas between the Shell and all of the Buttons, and the
performance seemed fine. Does your case's performance improve without
drawing the background image? Does using a Composite instead with a
background image set on it perform better for your case?

Grant

"Dominic Hanlan" <dominic@hanlan.org.uk> wrote in message
news:ilsjcm$8ni$1@news.eclipse.org...
> Thanks for the link.
> The problem is that the code works perfectly, it's just the speed of the
> button rendering that is the issue. If I have a standard composite as the
> parent, it's fine, if I have a canvas the speed is incredibly slow for
> each button to appear?????
>
> Regards
>
> /Dominic

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