[news.eclipse.platform.swt] Re: Drawing to GC

[grant_gayed@xxxxxxxxxx (Grant Gayed)]

This does it through JFace (direct to an swt Tree shouldn't be any
different w.r.t. creating the Image):

public static void main (String[] args) {
	final Display display = new Display();
	Shell shell = new Shell(display);
	shell.setBounds(10,10,200,200);
	TreeViewer tree = new TreeViewer(shell,SWT.NONE);
	tree.getTree().setBounds(10,10,140,140);
	tree.setLabelProvider(new ILabelProvider() {
		public Image getImage(Object element) {
			Image image = new Image (display, 16, 16);
			int random = (int)System.currentTimeMillis() % 2;
			Color color;
			if (random == 0) {
				color = display.getSystemColor (SWT.COLOR_RED);
			} else {
				color = display.getSystemColor (SWT.COLOR_BLUE);
			}
			GC gc = new GC (image);
			gc.setBackground (color);
			gc.fillOval (1, 1, 14, 14);
			gc.dispose ();
			return image;
		}
		public String getText(Object element) {
			return "node";
		}
		public void addListener(ILabelProviderListener listener) {}
		public void dispose() {}
		public boolean isLabelProperty(Object element, String property) {
			return false;
		}
		public void removeListener(ILabelProviderListener listener) {}
	});
	tree.setContentProvider(new ITreeContentProvider() {
		public Object[] getChildren(Object parentElement) {return null;}
		public Object getParent(Object element) {return null;}
		public boolean hasChildren(Object element) {return true;}
		public Object[] getElements(Object inputElement) {
			return new String[] {"",""};
		}
		public void dispose() {}
		public void inputChanged(Viewer viewer, Object oldInput, Object
newInput) {}
	});
	tree.setInput("");	
	shell.pack ();
	shell.open ();
	while (!shell.isDisposed ()) {
		if (!display.readAndDispatch ()) display.sleep (); 
	} 
	display.dispose ();
}

Grant



Angel Shishkov wrote:

> Hello,

> I would like to dynamically generate the labels for a Tree.  The labels must
> be circles with varying colors.  I don't have the labels as images in a
> file, so I need to create the Image dynamically in the code.  This is what
> I've tried:

> Image label = new Image(null, 15, 15);
> GC gc = new GC (label);
> gc.setBackground(ColorConstants.blue);
> gc.fillOval(0, 0, 15, 15);
> return label;

> However, the labels that get displayed by this are just black squares.  I
> have also tried:

> Image label = new Image(Display.getCurrent(), 15, 15);

> with the same effect.

> I have tried this with both a JFace TreeViewer by implementing the
> LabelProvider and an SWT Tree widget by using TreeItem.setImage(img);  Both
> methods produce a tree with black squares for labels.

> Is this the correct way to draw to a GC?  Am I missing something?

> Any help is greatly appreciated. Thanks!

> Angel