import org.eclipse.swt.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.layout.*;
import org.eclipse.swt.widgets.*;

/**
 * @author Thomas Singer
 */
public class MouseOverTest {

	public static void main(String[] args) {
		final Display display = new Display();

		final Shell shell = new Shell(display);
		shell.setLayout(new FillLayout());
		final Composite composite = new Composite(shell, SWT.NONE);

		final Label label = new Label(composite, SWT.NONE);
		label.setText("<- move here to see magenta");
		final Point labelSize = label.computeSize(SWT.DEFAULT, SWT.DEFAULT);
		label.setSize(labelSize);
		label.setLocation(50, 0);

		final Listener listener = new Listener() {
			private boolean mouseOver;

			@Override
			public void handleEvent(Event event) {
				if (event.type == SWT.Paint) {
					event.gc.setBackground(mouseOver ? display.getSystemColor(SWT.COLOR_MAGENTA) : composite.getBackground());
					event.gc.fillRectangle(0, 0, composite.getSize().x, labelSize.y);
				}
				else if (event.type == SWT.MouseEnter
				         || event.type == SWT.MouseMove
				         || event.type == SWT.MouseExit) {
					final boolean mouseOver = event.x >= 0 && event.x <= 50 && event.y >= 0 && event.y <= labelSize.y;
					if (this.mouseOver == mouseOver) {
						return;
					}

					this.mouseOver = mouseOver;
					composite.redraw();
				}
			}
		};
		composite.addListener(SWT.Paint, listener);
		composite.addListener(SWT.MouseEnter, listener);
		composite.addListener(SWT.MouseMove, listener);
		composite.addListener(SWT.MouseExit, listener);

		shell.setSize(400, 300);
		shell.open();

		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}

		display.dispose();
	}
}