drawpanel.java

Java大学基础教程V6前五章源码

// Fig. 4.19: DrawPanel.java
// Draws two crossing lines on a panel.
import java.awt.Graphics; 
import javax.swing.JPanel;

public class DrawPanel extends JPanel
{
   // draws an X from the corners of the panel
   public void paintComponent( Graphics g )
   {
      // call paintComponent to ensure the panel displays correctly
      super.paintComponent( g );
      
      int width = getWidth(); // total width   
      int height = getHeight(); // total height

      // draw a line from the upper-left to the lower-right
      g.drawLine( 0, 0, width, height );
      
      // draw a line from the lower-left to the upper-right
      g.drawLine( 0, height, width, 0 );
   } // end method paintComponent
} // end class DrawPanel


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