Name: sg39081 Date: 08/20/97


In JDK 1.1.4G, calling repaint() on a lightweight component
causes 2 calls to paint(). This bug has been introduced since JDK
1.1.3.
Ramifications: All products using lightweight components are significantly
slower than they need to be. I believe this deserves showstopper status.

Test case: Run the following Java application. Note that pressing
the Button causes only one "Repaint" message, but two "Paint" messages.
-----------------------------------------------
import java.awt.*;
import java.awt.event.*;
public class DoubleRepaint extends Frame implements ActionListener
{
  public static void main(String[] args)
  {
    (new DoubleRepaint()).setVisible(true);
  }
  public DoubleRepaint()
  {
    Button b = new Button("Press me");
    b.addActionListener(this);
    add(b, BorderLayout.SOUTH);
    _counter = new CounterComp();
    add(_counter);
    pack();
  }
  public void actionPerformed(ActionEvent e)
  {
    _counter.repaint();
  }
  private CounterComp _counter;
}
class CounterComp extends Component
{
  public Dimension getPreferredSize()
  {
    return new Dimension(50, 50);
  }
  public void repaint(long tm, int x, int y, int width, int height)
  {
    System.out.println("Repaint #" + (++_repaintCount));
    super.repaint(tm, x, y, width, height);
  }
  public void paint(Graphics g)
  {
    System.out.println("Paint #" + (++_paintCount));
  }
  private int _paintCount, _repaintCount;
}

company - Oracle , email - ###@###.###
======================================================================