图象缩放的一个问题

Question

public static BufferedImage zoom(BufferedImage image,float factorX,float factorY) {
      AffineTransform transform=AffineTransform.getScaleInstance(factorX,factorY);
      BufferedImageOp op=new AffineTransformOp(transform,AffineTransformOp.TYPE_BILINEAR);
      BufferedImage filteredImage=new BufferedImage(
            (int)(image.getWidth()*factorX),
            (int)(image.getHeight()*factorY),
            image.getType());
      op.filter(image, filteredImage);
      return filteredImage;
   }

Answer 1

可以试试下面的测试程序.
import java.awt.*;
import java.awt.event.*;
import java.awt.geom.*;
import java.awt.image.*;import javax.swing.*;
import javax.swing.event.*;public class image extends JApplet
{   public String imageName = "abc.gif";
   boolean isStandalone = false;
   JSlider slid;
   static ImageProcessingPanel panel;
   BufferedImage image,changedImage;   public static void main(String[] args) {
      image applet = new image();
      applet.imageName = "c:/abc.jpg";
      applet.isStandalone = true;
      JFrame frame = new JFrame();
      //EXIT_ON_CLOSE == 3
      frame.setDefaultCloseOperation(3);
      frame.setTitle("Applet Frame");
      frame.getContentPane().add(applet, BorderLayout.CENTER);
      applet.init();
      applet.start();
      frame.setSize(400,320);
      Dimension d = Toolkit.getDefaultToolkit().getScreenSize();
      frame.setLocation((d.width - frame.getSize().width) / 2, (d.height - frame.getSize().height) / 2);
      frame.setVisible(true);
   }
   Object P = "";
   boolean isIn = false;   public void processZoom(ChangeEvent e) {
      if(isIn)
         return;
      synchronized(P) {
         isIn = true;
      JSlider sld = (JSlider)e.getSource();
      float factor = (float)sld.getValue();
      if(factor < 0) {
         factor = -1/factor;
      }else if(factor == 0)
         factor = 1;
      System.out.println(""+factor);
      float fX = factor;
      float fY = factor;
      if(isHorizonFixed)fX=1.0f;
      if(isVertFixed)fY=1.0f;
      changedImage = zoom(image,fX,fY);
      panel.redraw(changedImage);
      isIn = false;
      }
   }
   boolean isHorizonFixed=false;
   boolean isVertFixed = false;   public static BufferedImage zoom(BufferedImage image,float factorX,float factorY) {
      AffineTransform transform=AffineTransform.getScaleInstance(factorX,factorY);
      BufferedImageOp op=new AffineTransformOp(transform,AffineTransformOp.TYPE_BILINEAR);
      BufferedImage filteredImage=new BufferedImage(
            (int)(image.getWidth()*factorX),
            (int)(image.getHeight()*factorY),
            image.getType());
      op.filter(image, filteredImage);
      return filteredImage;
   }
   private void pp(ChangeEvent e) {
      isHorizonFixed = boxH.isSelected();
      isVertFixed = boxV.isSelected();
      System.out.println("Ho:"+isHorizonFixed+" Ve:"+isVertFixed);
   }
 JCheckBox boxH = new JCheckBox("Hori");
 JCheckBox boxV = new JCheckBox("Vert");
   public void init()
   {
      Container contentPane=getContentPane();
      panel=new ImageProcessingPanel();
      contentPane.add(panel,"Center");
      JSlider slid = new JSlider(JSlider.HORIZONTAL,-10,3,0);
      slid.addChangeListener(new ChangeListener() {
         public void stateChanged(ChangeEvent e) {
            processZoom(e);
         }
      });
      JPanel pnlControl = new JPanel();
      contentPane.add(pnlControl,"South");
      pnlControl.add(slid);
      boxH.addChangeListener(new ChangeListener() {
         public void stateChanged(ChangeEvent e) {
            pp(e);
         }});
      boxV.addChangeListener(new ChangeListener() {
         public void stateChanged(ChangeEvent e) {
            pp(e);
         }});
      pnlControl.add(boxH);
      pnlControl.add(boxV);
//      contentPane.add(boxV,"South");
      try{
         Image loadedImage;
         if(isStandalone)
      loadedImage= new ImageIcon(imageName).getImage();
   else
    loadedImage=getImage(getCodeBase(),imageName);
 image=load(panel,loadedImage);
 panel.redraw(image);
 //init()
 }catch(Exception e){e.printStackTrace();}
   }
   static MediaTracker tracker;
   public static BufferedImage load(Component panel, Image loadedImage){
      tracker=new MediaTracker(panel);
      tracker.addImage(loadedImage,0);
      try{ tracker.waitForID(0);}
      catch(InterruptedException e){}      BufferedImage image=new BufferedImage(
                 loadedImage.getWidth(null),
                 loadedImage.getHeight(null),
                 BufferedImage.TYPE_INT_RGB);
      Graphics2D g2=image.createGraphics();
      g2.drawImage(loadedImage,0,0,null);
      g2.drawImage(loadedImage,100,100,null);
      return image;
   }}class ImageProcessingPanel extends JPanel
{
   private BufferedImage image;   public void paintComponent(Graphics g)
   {
      super.paintComponent(g);
      if (image!=null)
     g.drawImage(image,5,5,null);
   }   public void redraw(BufferedImage image)
   {
      this.image=image;
      repaint();
   }}