[news.eclipse.modeling.gmf] Re: Layout issue with Polygon in Composite F

[c.muth@xxxxxx (Christian Muth)]

Hi Julia,


thanks for the hints! Although I already knew these documentation 
resources I rather tried composing the figure just with .gmfgraph which 
wont work for Polygons in the given scenario.

So I followed your advice and created RhombFigure (everyone feel free to 
use, modify and distribute):


__________________________________________________________________________
package org.eclipse.draw2d;

import org.eclipse.draw2d.Graphics;
import org.eclipse.draw2d.RectangleFigure;
import org.eclipse.draw2d.geometry.Point;
import org.eclipse.draw2d.geometry.PointList;
import org.eclipse.draw2d.geometry.Rectangle;

/**
* Draws a filled rhomb whose size is determined by its bounds.
* Each corner of the rhomb matches the middle of the corresponding edge 
* given by {@link #getBounds()}.
*/
public class RhombFigure extends RectangleFigure {
	private PointList cachedPointList;
	private Rectangle oldBounds;

	/**
	 * Constructs a new RhombFigure, sets <code>fill</code> to 
<code>true</code>.  
	 */
	public RhombFigure() {
		super();
		this.setFill(true);
	}

	/**
	 * Fills the rhomb.
	 * @see org.eclipse.draw2d.Shape#fillShape(org.eclipse.draw2d.Graphics)
	 */
	@Override
	protected void fillShape(Graphics graphics) {
		graphics.pushState();
		graphics.fillPolygon(getPointList());
		graphics.popState();
	}

	/**
	 * Outlines the rhomb.
	 * @see org.eclipse.draw2d.Shape#outlineShape(org.eclipse.draw2d.Graphics)
	 */
	@Override
	protected void outlineShape(Graphics graphics) {
		graphics.pushState();
		graphics.drawPolygon(getPointList());
		graphics.popState();
	}

	/**
	 * Returns the PointList for a rhomb style polygon filling the 
<code>Rectangle</code>
	 * returned by {@link org.eclipse.draw2d.RectangleFigure#getBounds()}.
	 * 
	 * @return the desired <code>PointList</code> containing absolute 
coordinates
	 */
	private PointList getPointList() {
		Rectangle bounds = getBounds();

		if (oldBounds == null || !(bounds.equals(oldBounds))) {
			// need to recalculate since bounds changed
			
			// use a copy - otherwise oldBounds never changes ;o)
			this.oldBounds = bounds.getCopy();

			// leave 1 px margin on each edge to avoid clipping
			int left = bounds.x + 1;
			int right = (left + bounds.width) - 2;
			int center = left + (int)Math.floor((right - left) / 2);

			int top = bounds.y + 1;
			int bottom = top + bounds.height - 2;
			int middle = top + (int)Math.floor((bottom - top) / 2);

			this.cachedPointList = new PointList();
			this.cachedPointList.addPoint(new Point(center, top));
			this.cachedPointList.addPoint(new Point(right, middle));
			this.cachedPointList.addPoint(new Point(center, bottom));
			this.cachedPointList.addPoint(new Point(left, middle));
		}
		
		return this.cachedPointList;
	}
}
__________________________________________________________________________

And modified my .gmfgraph to use the new Custom Figure:


   <descriptors
       name="ResourceFigure">
     <actualFigure
         xsi:type="gmfgraph:Rectangle"
         name="ResourceFigure"
         outline="false"
         fill="false">
       <layout
           xsi:type="gmfgraph:StackLayout"/>
       <children
           xsi:type="gmfgraph:Rectangle"
           name="Inner"
           outline="false"
           fill="false">
         <layout
             xsi:type="gmfgraph:GridLayout"
             equalWidth="false"/>
         <foregroundColor
             xsi:type="gmfgraph:ConstantColor"
             value="gray"/>
         <children
             xsi:type="gmfgraph:CustomFigure"
             name="MyRhombFigure"
             qualifiedClassName="org.eclipse.draw2d.RhombFigure">
           <layoutData
               xsi:type="gmfgraph:GridLayoutData"
               verticalAlignment="BEGINNING"/>
           <backgroundColor
               xsi:type="gmfgraph:ConstantColor"
               value="yellow"/>
           <size
               x="30"
               y="30"/>
         </children>
         <children
             xsi:type="gmfgraph:Rectangle"
             name="Body">
           <layoutData
               xsi:type="gmfgraph:GridLayoutData"
               grabExcessHorizontalSpace="true"
               grabExcessVerticalSpace="true"
               verticalAlignment="FILL"
               horizontalAlignment="FILL"/>
           <backgroundColor
               xsi:type="gmfgraph:ConstantColor"
               value="gray"/>
           <size
               x="120"
               y="200"/>
         </children>
       </children>
     </actualFigure>
   </descriptors>



Maybe someone might find this useful...


Thanks all

Christian