Java by API/org.eclipse.swt.events/PaintListener

implements PaintListener

   <source lang="java">

import org.eclipse.swt.SWT; import org.eclipse.swt.events.PaintEvent; import org.eclipse.swt.events.PaintListener; import org.eclipse.swt.layout.FillLayout; import org.eclipse.swt.widgets.Canvas; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; public class MainClass {

 public static void main(String[] a) {
   final Display d = new Display();
   final Shell shell = new Shell(d);
   shell.setSize(250, 200);
   shell.setLayout(new FillLayout());
   Canvas drawingCanvas = new Canvas(shell, SWT.NONE);
   drawingCanvas.addPaintListener(new ArcExamplePaintListener());
   drawingCanvas.redraw();
   
   shell.open();
   while (!shell.isDisposed()) {
     if (!d.readAndDispatch())
       d.sleep();
   }
   d.dispose();
 }

} class ArcExamplePaintListener implements PaintListener {

 public void paintControl(PaintEvent e) {
   Canvas canvas = (Canvas) e.widget;
   int x = canvas.getBounds().width;
   int y = canvas.getBounds().height;
   e.gc.setBackground(e.display.getSystemColor(SWT.COLOR_BLACK));
   e.gc.fillArc((x - 200) / 2, (y - 200) / 2, 200, 200, 0, 90);
 }

}

      </source>