displayimage.java

非常好的java事例以及带源码事例的java2教程

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

public class DisplayImage extends JApplet
{
  public void init()
  {
    Image image = null;
    try
    {
      // Image from a file specified by a URL
      image = getImage(new URL(getCodeBase(),"Images/wrox_logo.gif")); 
    }

    catch(MalformedURLException e)
    {
      System.out.println("Failed to create URL:\n" + e);
    }

    int imageWidth = image.getWidth(this);                     // Get its width
    int imageHeight = image.getHeight(this);                   // and its height
    if(imageWidth != -1 && imageHeight != -1)                  // If they are available
      resize(imageWidth,imageHeight);                          // set applet size to fit

    ImagePanel imagePanel = new ImagePanel(image);  // Create panel showing the image

    getContentPane().add(imagePanel);               // Add the panel to the content pane
  }

  public boolean imageUpdate(Image img,         // Reference to the image
                             int flags,         // Flags identifying what is available
                             int x,             // x coordinate
                             int y,             // y coordinate
                             int width,         // Image width
                             int height)        // Image height
  {
    if((flags & WIDTH) > 0 && (flags & HEIGHT) > 0)
    {
      resize(width,height);                        // Set applet size to fit the image
      repaint();                                   // Repaint the applet in its new size
      return true; 
    }
    else
      return false;                                // More info required
  }

   // Class representing a panel displaying an image
   class ImagePanel extends JPanel
   {
     public ImagePanel(Image image)
     {
      this.image = image;
     }

     public void paint(Graphics g)
     {
       g.drawImage(image, 0, 0, this);                        // Display the image
     }

     Image image;                                             // The image
   }
}