例8-8.java

用Java和XML建立试题库管理系统,试题库管理系统的设计

//example 8-8
import java.applet.Applet;
import java.awt.*;
import java.awt.image.*;
public class tt extends Applet
{
   Image baseImage,newImage;
   int sx,sy,dx,dy,w,h;
   boolean selected;
   public void init()
   {
   	 baseImage=getImage(getCodeBase(),"duke.gif");
   	 newImage=baseImage;
   }
   public void paint(Graphics g)
   {
   	  g.drawImage(baseImage,0,0,this);
   	  g.drawImage(newImage,dx,dy,this);
   }
   public boolean mouseDown(Event evt,int x,int y)
   {
   	  if(!selected)
   	  {
   	  	sx=x;sy=y;selected=true;
   	  }
   	  else
   	  {
   	  	dx=x;dy=y;newImage=cropImage();
   	  	repaint();
   	  	selected=false;
   	  }
   	  return true;
   }
   public boolean mouseDrag(Event evt,int x,int y)
   {
   	  showStatus("from("+sx+","+sy+")to("+x+","+y+")");
   	  return true;
   }
   public boolean mouseUp(Event evt,int x,int y)
   {
   	  if(selected)
   	  {
   	  	w=Math.abs(x-sx);h=Math.abs(y-sy);
   	  	getGraphics().drawRect(sx,sy,w,h);
   	  }
   	  return true;
   }
   Image cropImage()
   {
   	  ImageFilter filter=new CropImageFilter(sx,sy,w,h);
   	  ImageProducer producer=new FilteredImageSource(baseImage.getSource(),filter);
   	  Image img=createImage(producer);
   	  return img;
   }
}