imageapplet.java

《Java实例入门》所有实例的源代码。所有的源文件都是.java文件

import java.applet.Applet;
import java.awt.*;
import java.awt.image.*;

public class imageApplet extends Applet
{

    Image img = null;
    MediaTracker tracker = null;
    int Mx = 0;
    int My = 0;							//鼠标按下的位置
    int width = 0;
    int height = 0;						//选定区域的宽和高

    public void init()
    {
        img = getImage(getCodeBase(), "fun.jpg");		//下载图像
        tracker = new MediaTracker(this);
        tracker.addImage(img, 0);
        try
        {
            tracker.waitForAll();				//等待图像完全下载
        }
        catch(InterruptedException _ex) { }
        Mx = -1;
        My = -1;
        resize(200,200) ;
        width = 100;
        height = 100;
    }

    public boolean mouseDown(Event event, int i, int j)
    {
        Mx = i;
        My = j;							//记录鼠标按下的位置
        repaint();
        return true;
    }

    public void paint(Graphics g)
    {
    	//由于类component实现了接口ImageObserver，所以方法drawImage
	//中的ImageObserver型参数为this
        g.drawImage(img, 0, 30, this);				//显示原始图像
        g.drawString("This is the original picture", 10,20);
        if(Mx > 0)
        {
            int i = Math.max(0, Mx - width / 2);
            int j = Math.max(0, My - height / 2);		//计算左上角图标
             g.drawString("Using copyArea method", 345,20);
             g.copyArea(i, j, width, height, 336, j);
             g.drawString("Using clipRect method", 490,20);	//将图像的一部分拷贝
             g.clipRect(440+i, j, width, height);		        //设置裁减区域
             g.drawImage(img, 440,0, this);

        }
    }

}