shapesapplet.java

高级java2 大学教程(含源码,经典的Java学习教程

// Fig. 10.x: ShapesApplet.java
// Applet that demonstrates a Java2D GeneralPath.
package com.deitel.advjhtp1.jsp.applet;

// Java core packages
import java.applet.*;
import java.awt.event.*;
import java.awt.*;
import java.awt.geom.*;

// Java extension packages
import javax.swing.*;

public class ShapesApplet extends JApplet {
   
   // initialize the applet
   public void init()
   {
      // obtain color parameters from XHTML file
      try {
         int red = Integer.parseInt( getParameter( "red" ) );
         int green = Integer.parseInt( getParameter( "green" ) );
         int blue = Integer.parseInt( getParameter( "blue" ) );
      
         Color backgroundColor = new Color( red, green, blue );
         
         setBackground( backgroundColor );
      }
      
      // if there is an exception while processing the color
      // parameters, catch it and ignore it
      catch ( Exception exception ) {
         // do nothing
      }
   }

   public void paint( Graphics g )
   {
      // create arrays of x and y coordinates
      int xPoints[] = 
         { 55, 67, 109, 73, 83, 55, 27, 37, 1, 43 };
      int yPoints[] = 
         { 0, 36, 36, 54, 96, 72, 96, 54, 36, 36 };

      // obtain reference to a Graphics2D object
      Graphics2D g2d = ( Graphics2D ) g;

      // create a star from a series of points
      GeneralPath star = new GeneralPath();

      // set the initial coordinate of the GeneralPath
      star.moveTo( xPoints[ 0 ], yPoints[ 0 ] );

      // create the star--this does not draw the star
      for ( int k = 1; k < xPoints.length; k++ )
         star.lineTo( xPoints[ k ], yPoints[ k ] );

      // close the shape
      star.closePath();

      // translate the origin to (200, 200)
      g2d.translate( 200, 200 );

      // rotate around origin and draw stars in random colors
      for ( int j = 1; j <= 20; j++ ) {
         g2d.rotate( Math.PI / 10.0 );
         
         g2d.setColor(
            new Color( ( int ) ( Math.random() * 256 ),
                       ( int ) ( Math.random() * 256 ),              
                       ( int ) ( Math.random() * 256 ) ) );
         
         g2d.fill( star );   // draw a filled star
      }
   }
}

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