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Multiple decorators : expected behaviour? [message #726093]

Fri, 16 September 2011 14:31

Hernan Gonzalez

Messages: 188
Registered: October 2010
Location: Buenos Aires, Argentina

Senior Member

The method ToolBehaviorProvider.getDecorators() returns an array of Decorators for a pictogram element. What is the expected behaviour when more than one is returned? I expected that they were displayed side by side, but it seems I was too optimistic Razz

For example, in the tutorial:

public class TutorialToolBehaviorProvider extends DefaultToolBehaviorProvider {
 ...
  @Override
  public IDecorator[] getDecorators(PictogramElement pe) {
    IFeatureProvider featureProvider = getFeatureProvider();
    Object bo = featureProvider.getBusinessObjectForPictogramElement(pe);
    if (bo instanceof EClass) {
        IDecorator imageRenderingDecorator1 = new ImageDecorator(IPlatformImageConstants.IMG_ECLIPSE_ERROR);
        imageRenderingDecorator1.setMessage("Error");
        IDecorator imageRenderingDecorator2 = new ImageDecorator(IPlatformImageConstants.IMG_ECLIPSE_INFORMATION);
        imageRenderingDecorator2.setMessage("Info"); 
        return new IDecorator[] { imageRenderingDecorator1,imageRenderingDecorator2};
    }
    return super.getDecorators(pe);
  }

The two images are placed one in top of the other - only the last one is visible. Is this right?

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Re: Multiple decorators : expected behaviour? [message #726103 is a reply to message #726093]

Fri, 16 September 2011 15:10

Hernan Gonzalez

Messages: 188
Registered: October 2010
Location: Buenos Aires, Argentina

Senior Member

Well, after looking inside the code, (PictogramElementDelegate.decorateFigure) it seems that decorators are just stacked, so that's all

I wonder if some alternative decorators could be implemented, apart from ImageDecorator... specially I'd like to have some "highligting" decorators, either drawing some border or changing the background colour. I'll give it a look.

Another thing: I see that the decorateFigure() is called for every figure refresh (eg, when I move it), and that it instantiates a new DecoratorImageFigure() each time. This extends a ImageFigure (draw2d), which states in its docs: "Note that it is the client's responsibility to dispose the given image. There is no "free" resource management in draw2d." I know little of Draw2d/SWT, can someone who knows better confirm that there is no danger of resource leak here?

[Updated on: Fri, 16 September 2011 15:10]

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Re: Multiple decorators : expected behaviour? [message #726544 is a reply to message #726103]

Sun, 18 September 2011 15:16

Andreas Graf

Messages: 211
Registered: July 2009

Senior Member

Hi Hernan,

I haven't tried this, but there is this piece of code int PictogramElementDelegate:

if (decorator instanceof ILocation) {
				ILocation location = (ILocation) decorator;
				boundsForDecoratorFigure.setLocation(location.getX(), location.getY());
			}

which makes me think if you could extend the ImageDecorator, implement ILocation and provide your own location?

That would put the responsibility of decorator layout to you, but at least it might be possible.

Andreas

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Re: Multiple decorators : expected behaviour? [message #726658 is a reply to message #726544]

Mon, 19 September 2011 07:44

Felix Velasco

Messages: 43
Registered: July 2009

Member

IImageDecorator already implements ILocation, so you just have to call setX() and setY() as you wish...

        IImageDecorator imageRenderingDecorator1 = new ImageDecorator(IPlatformImageConstants.IMG_ECLIPSE_ERROR);
        imageRenderingDecorator1.setMessage("Error");
        imageRenderingDecorator1.setX(4); //default
        imageRenderingDecorator1.setY(10);

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