SWT Java Tutorial

Image image1 =  new Image(display, 300, 200);
Image image2 = new Image(display, myRect);
Because an Image is a Drawable, you can pass it to a GC to draw on it:

GC gc = new GC(image);

import org.eclipse.swt.SWT;
import org.eclipse.swt.events.PaintEvent;
import org.eclipse.swt.events.PaintListener;
import org.eclipse.swt.graphics.GC;
import org.eclipse.swt.graphics.Image;
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 ImageEmpty {
  public static void main(String[] args) {
    final Display display = new Display();
    final Shell shell = new Shell(display);
    shell.setText("Canvas Example");
    shell.setLayout(new FillLayout());
    Canvas canvas = new Canvas(shell, SWT.NONE);
    canvas.addPaintListener(new PaintListener() {
      public void paintControl(PaintEvent e) {
        Image image = new Image(display, 300, 200);
        GC gc = new GC(image);
        gc.drawLine(10,10,200,200);
        gc.dispose();
        e.gc.drawImage(image, 10, 10);
        image.dispose();
      }
    });
    shell.open();
    while (!shell.isDisposed()) {
      if (!display.readAndDispatch()) {
        display.sleep();
      }
    }
    display.dispose();
  }
}