[udig-devel] Problem with my MapGraphic implementation. Please Help

[Jesse Eichar]

Hi.

It sounds to me like since you want actual animation you may want to  
use an animation instead.  For now the API is rather poor.  I plan on  
integrating the timing framework later on.  But for now look into  
IAnimation and AnimationUpdater to run the animation.

The problem with using an animation is that it something must start  
it.  I'd suggest that when your map graphic is called to render it  
starts the animation (if it is not already running).  Draw commands  
(and IAnimations) are drawn on the Acetate layer and are removed  
during certain rendering actions, such as a zoom in.  Because of this  
you may find that you have to put a timestamp on you animation to  
make sure that it keeps running and isn't disposed of.

I'm not sure this email completely makes sense.  Please let me know  
if you have a question.

Jesse

On Oct 8, 2007, at 8:57 AM, Ingmar Eveslage wrote:

>
> Hello,
>
> I have a problem with the plugin I developed. I implemented a  
> MapGraphic
> Extension which draw rectangles on a given position on the map.
> I also implemented a thread which modifies the data that is drawn  
> and then
> calls the Layer.refresh(Envelope) function to draw the MapGraphic  
> again with
> the updated data. Then the thread takes a short break, modifies the  
> data
> again and refreshes the layer again, and so on.
>
> The MapGrahpics implementation uses double buffering and draws the  
> hidden
> painted picture (a java.awt.image.BufferedImage) in the last line  
> of the
> override draw(MapGraphicContext context) function.
>
> All works fine, but because the MapGraphic.draw function takes some  
> time (i
> paint many rectangles, and sometime circles) it has not finished  
> before the
> "updating-thread" calls Layer.refresh again. if this happens the  
> MapGraphics
> layer gets totally blank. As i said: only if the Layer.refresh call is
> before the MapGrahics.draw function finishes its last redraw.
>
> This is very distracting, because the MapGraphic layer with all my
> rectangles and circles begin to flicker and sometimes when there  
> are many
> updates the MapGraphic layer gets deleted short after its ready with
> painting.
>
> I hope someone can help me. I tried to find a way to suspend the  
> updating
> thread until the MapGraphic layer completed the draw method, but i  
> didn't
> find the right api call. after hours of debugging i could not even  
> find the
> place where the layer gets blank.
>
> So please help me.
>
> Thanks forward
> 	Ingmar
>
> For info:
>
> I use Eclipse 3.2 and the uDig SDK 1.1RC11 on a Intel Mac.
> -- 
> View this message in context: http://www.nabble.com/Problem-with-my- 
> MapGraphic-implementation.-Please-Help-tf4588290.html#a13096935
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>
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