Name: krC82822 Date: 05/02/2000


2 May 2000, eval1127@eng -- reproducible with 1.3.0-C on NT 4.0 SP 6a. Task Manager must be used to kill the process.
(Works fine with double-buffering turned off.)

java version "1.3.0rc3"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0rc3-Z)
Java HotSpot(TM) Client VM (build 1.3.0rc3-Z, mixed mode)

If we set a large x or y value for a point's coordinate, Graphics.drawLine()
freezes in the paint() method for Swing components in
DoubleBuffer mode (under Windows NT).

Try the following program :

If you run this DrawLineFreeze class, NT freezes after the JFrame becomes visible.
This happens when JPanel's paint() is invoked with DoubleBuffer mode
//----------------------------------------------------------
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import java.util.*;

class DrawLineFreeze extends JFrame {
   JButton test1, test2;
    
   public static void main( String[] arg ){
      JFrame w = new DrawLineFreeze();
      w.setDefaultCloseOperation(3);
      w.setSize( 500, 500 );
      w.setVisible( true );
   }
   DrawLineFreeze(){
      FreezePanel panel = new FreezePanel();
      Container pane = getContentPane();
      pane.add( panel, BorderLayout.CENTER );
      
RepaintManager.currentManager(getRootPane()).setDoubleBufferingEnabled(true);
      
//RepaintManager.currentManager(getRootPane()).setDoubleBufferingEnabled(false);
   }

  class FreezePanel extends JPanel {
    public void paint( Graphics g ){
         g.drawLine( -100000, -100000, 100000, 100000 );
         g.drawLine( -100000, 100000, 500, 0 );
    }
  }
}
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(Review ID: 103963)
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