drawpane.java

来自「Java编程100例,提供了很多经典实例来说明Java」· Java 代码 · 共 66 行

package jrasterdemo1;

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


class DrawPane extends JPanel{

    BufferedImage bimage,bimage1,bimage2;


    public DrawPane(){

      Image image = this.getToolkit().getImage(ClassLoader.getSystemResource("images/image.jpg"));

      MediaTracker mt = new MediaTracker(this);
      mt.addImage(image,0);

      try{
        mt.waitForAll();

      }catch(Exception err){
        err.printStackTrace();
      }

      if (image.getWidth(this) == -1){
        System.out.println("Could not get the image");
        System.exit(-1);
      }

      this.setSize(image.getWidth(this),image.getHeight(this));

      bimage1 = new BufferedImage(image.getWidth(this),image.getHeight(this),BufferedImage.TYPE_INT_ARGB);
      Graphics2D g2D = bimage1.createGraphics();
      g2D.drawImage(image,0,0,this);

      bimage = bimage1;
    }

    public void turnBufferedImage(){

      bimage2 = new BufferedImage(bimage1.getWidth(),bimage1.getHeight(),bimage1.getType());

      DataBuffer db1 = bimage1.getRaster().getDataBuffer();
      DataBuffer db2 = bimage2.getRaster().getDataBuffer();

      for (int i=db1.getSize()-1,j=0;i>=0;i--,j++){
        db2.setElem(j,db1.getElem(i));
      }

    }

    public void update(Graphics g){
      g.clearRect(0,0,this.getWidth(),this.getHeight());
      this.paintComponent(g);
    }

    public void paintComponent(Graphics g){
      super.paintComponent(g);
      Graphics2D g2d = (Graphics2D)g;
      g2d.drawImage(bimage,0,0,this);
    }
  }