rainpanel.java

外文网站上下载的JSP图形编程(3)

import java.awt.Color;
import java.awt.Graphics;

import javax.swing.JPanel;

/*
 * Created on Jul 3, 2003
 *
 * To change the template for this generated file go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */

/**
 * @author Fabian Jones AD Summer Intern 2003
 *
 * To change the template for this generated type comment go to
 * Window>Preferences>Java>Code Generation>Code and Comments
 */
public class RainPanel extends JPanel{
	private static int DEFAULT_WIDTH = 500;
	private static int DEFAULT_HEIGHT = 500;
	private static int NUM_DROPS = 500;
	
	private RainDrop[] rainDrops = new RainDrop[500];
	
	public RainPanel(){
		createRainDrops();
		createPanel();
	}
	
	private void createRainDrops(){
		for(int i = 0; i < rainDrops.length; ++i){
			createRainDrop(i);
		}
	}
	
	private void createRainDrop(int index){
		int randomX = (int) (Math.random()*500);
		int randomY = (int) (Math.random()*300);
		int randomV = (int) (Math.random()*10);
			
		rainDrops[index] = new RainDrop(randomX, randomY, randomV);
	}
	
	private void createPanel(){
		this.setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
		this.setBackground(Color.WHITE);
	}
	
	public void paint(Graphics g){
		for(int i = 0; i < rainDrops.length; ++i){
			rainDrops[i].paint(g);
			
			if(rainDrops[i].x > DEFAULT_WIDTH || rainDrops[i].y > DEFAULT_HEIGHT){
				createRainDrop(i);
			}
		}
	}
}