drawpane.java

一些基本的代码,还有一些事例.值得一看

package jtransformdemo;

import java.awt.*;
import javax.swing.JPanel;
import java.awt.image.*;
import java.awt.color.*;
import java.awt.geom.*;

public class DrawPane extends JPanel {
  private BorderLayout borderLayout1 = new BorderLayout();
  Image image;
  BufferedImage bimage;
  BufferedImage bimageSrc;
  BufferedImage bimageDest;
  Graphics2D g2D;

  AffineTransform transform = new AffineTransform();
  double scaleX = 1.0;
  double scaleY = 1.0;




  public DrawPane() {
    try {
      jbInit();
    }
    catch(Exception ex) {
      ex.printStackTrace();
    }
  }
  void jbInit() throws Exception {
    this.setLayout(borderLayout1);

    loadImage();

    createBufferedImage();
    bimage = bimageSrc;
    this.setSize(image.getWidth(this),image.getHeight(this));
  }

  public void loadImage(){
    //image = Toolkit.getDefaultToolkit().createImage("images/image.jpg");
   // System.out.println(ClassLoader.getSystemResource("images/image.jpg"));
    image = this.getToolkit().createImage(ClassLoader.getSystemResource("images/image.jpg"));
    MediaTracker mt = new MediaTracker(this);
    mt.addImage(image,0);

    try{
      mt.waitForAll();
    }catch(Exception err){
      System.err.println("Could not load the image.");

    }

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

  }

  public void createBufferedImage(){
    bimageSrc = new BufferedImage(image.getWidth(this),image.getHeight(this),
        BufferedImage.TYPE_INT_ARGB);

    g2D = bimageSrc.createGraphics();
    g2D.drawImage(image,0,0,this);

    bimageDest = new BufferedImage(image.getWidth(this),image.getHeight(this),
                                   BufferedImage.TYPE_INT_ARGB);

  }

  public void applyFilter(){
    transform.setToScale(this.scaleX,this.scaleY);
    System.out.println("scale"+this.scaleX+"  "+this.scaleY);
    AffineTransformOp ato = new AffineTransformOp(transform,null);

    bimageDest.createGraphics().clearRect(0,0,bimageDest.getWidth(this),
        bimageDest.getHeight(this));

    ato.filter(bimageSrc,bimageDest);
    bimage = bimageDest;


  }


  public void reset(){
    g2D.setColor(Color.black);
    g2D.clearRect(0,0,image.getWidth(this),image.getHeight(this));
    g2D.drawImage(image,0,0,this);

    bimage = bimageSrc;

  }

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

  }
  public void paintComponent(Graphics g){
    super.paintComponent(g);
    Graphics2D g2 = (Graphics2D)g;
    g2.drawImage(bimage,0,0,this);

  }
}