bundles/org.eclipse.rap.gef.demo/src/org/eclipse/draw2d/examples/swt/InheritBackgroundExample.java

package org.eclipse.draw2d.examples.swt;

import org.eclipse.draw2d.ColorConstants;
import org.eclipse.draw2d.FigureCanvas;
import org.eclipse.draw2d.Label;
import org.eclipse.swt.SWT;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Composite;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Group;
import org.eclipse.swt.widgets.Shell;

public class InheritBackgroundExample {

	static Shell shell;
	static Image bg;
	
	static {
		bg = new Image(null, 10, 800);
		GC gc = new GC(bg);
		gc.setForeground(ColorConstants.white);
		gc.setBackground(ColorConstants.lightGreen);
		gc.fillGradientRectangle(0, 0, 300, 400, true);
		gc.setForeground(ColorConstants.lightGreen);
		gc.setBackground(ColorConstants.white);
		gc.fillGradientRectangle(0, 400, 300, 400, true);
		gc.dispose();
	}

	public static void main(String[] args) {
		Display d = Display.getDefault();
		shell = new Shell(d, SWT.SHELL_TRIM);
		shell.setText("Figure Canvas inheriting background from parent Composite");
		shell.setLayout(new GridLayout(2, false));
		shell.setBackgroundImage(bg);
		shell.setBackgroundMode(SWT.INHERIT_FORCE);

		FigureCanvas canvas;

		canvas = createCanvas(shell,
				SWT.DOUBLE_BUFFERED | SWT.BORDER | SWT.NO_REDRAW_RESIZE | SWT.V_SCROLL | SWT.H_SCROLL,
				"Paints Background");
		canvas.setBackground(ColorConstants.orange);
		
		canvas = createCanvas(shell,
				SWT.DOUBLE_BUFFERED | SWT.BORDER | SWT.NO_REDRAW_RESIZE | SWT.V_SCROLL | SWT.H_SCROLL,
				"Inherits Background");
		canvas.getLightweightSystem().getRootFigure().setOpaque(false);

		shell.pack();
		shell.open();
		while (!shell.isDisposed())
			while (!d.readAndDispatch())
				d.sleep();
	}

	private static FigureCanvas createCanvas(Composite parent, int style, String text) {
		Group group = new Group(parent, SWT.NONE);
		group.setLayoutData(new GridData(GridData.FILL_BOTH));
		group.setText(text);
		parent = group;
		group.setLayout(new FillLayout());
		
		FigureCanvas canvas = new FigureCanvas(style, parent);
		canvas.setContents(new Label(
				"This is a figure canvas\n" +
				"with a label.  The background\n" +
				"is either painted by the root\n" +
				"figure, or by the operating system.\n" +
				"Note that vertical scrolling may not be\n" +
				"as fast when the background from the\n" +
				"parent is inherited."));
		return canvas;
	}

}