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  1. JDK
  2. JDK-4252578

Program hang in JPanel with large Graphics.drawLine

    Details

    • Type: Bug
    • Status: Resolved
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 1.2.0
    • Fix Version/s: 1.4.0
    • Component/s: client-libs
    • Labels:
    • Subcomponent:
      2d
    • Resolved In Build:
      beta3
    • CPU:
      x86
    • OS:
      windows_95

      Description



      Name: rlT66838 Date: 07/08/99


      I discovered my Java application to hang while zooming in on
      a graphics repaint while drawing lines.

      I experimented and determined it happens with
      drawLine(x1,y1,x2,y2) when (x2-x1)*(y2-y1)>2^30 or so.

      This happens for lines as small as drawLine(0,0,32900,32900).
      That's significantly larger than the screen resolution,
      but when I'm zooming in on a small part of my image, this
      happens quite easily.

      Included is an example program. It draws:
      drawLine(0,0,rad,rad), with rad=32000 and each time a
      "repaint" button is pressed, rad is increased by 100.
      Pressing "repaint" 9 times will cause it to fail at rad=32900.

      I used this program to test the limits. The error will occur
      on any little program with a drawLine which exceeds this limit.

      In the very least, the bug should be fixed so the program
      doesn't hang - it could just draw nothing.

      Thanks!

      ********************************
      //redraw4.java
      //7/7/99

      import java.awt.*;
      import java.awt.event.*;
      import javax.swing.*;

      public class redraw4 extends JFrame
        implements ActionListener
      {
        static redraw4 frame = new redraw4("Drawing test");
        static Dimension d=new Dimension(200,200);

        test t=new test();
        int rad=32000;

        redraw4(String x)
        {
          super(x);

          Container c=getContentPane();
          c.setLayout(new BorderLayout());
          c.add(t,BorderLayout.CENTER);
          Button b=new Button("repaint");
          b.addActionListener(this);
          c.add(b,BorderLayout.NORTH);
        }

        public void actionPerformed(ActionEvent e)
        {
          String arg = e.getActionCommand();
          if (arg.equals("repaint")) t.repaint();
        }

        public static void main(String[] args)
        {
            frame.addWindowListener
            ( //allow application to close with x button.
              new WindowAdapter()
              {
                public void windowClosing(WindowEvent e) {System.exit(0);}
              }
            );

            frame.pack();
            frame.setVisible(true);
        }

        class test extends JPanel
        {
          public test()
          {
            super();
          }

          public Dimension getPreferredSize() { return d; }

          public void draw(Graphics g)
          {
            g.setXORMode(getBackground());
            g.setColor(Color.white);
            g.setPaintMode();
            g.drawString("drawLine(0,0,"+rad+","+rad+")",10,100);
            g.drawLine(0,0,rad,rad);
            rad=(int)(rad+100);
          }

          public void paint(Graphics g)
          {
            super.paint(g);
            draw(g);
          }
        }
      }
      (Review ID: 85334)
      ======================================================================

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              • Assignee:
                tdv Dmitri Trembovetski (Inactive)
                Reporter:
                rlewis Roger Lewis (Inactive)
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                  Updated:
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