/**
*
*/
package com.lideedu.randompic;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;
import javax.imageio.ImageIO;
/**
* @author Administrator
*
*/
public class RandomPic {
Random random = new Random();
private OutputStream desc;
public RandomPic(OutputStream desc)
{
this.desc=desc;
}
//返回的是生成的验证码
public String generate() throws IOException
{
BufferedImage image = new BufferedImage(60, 20,BufferedImage.TYPE_INT_RGB);
// 获取图形上下文
Graphics g = image.getGraphics();
g.setColor(getRandColor(200, 250));//设置画笔颜色
g.fillRect(0, 0, 60, 20);//用该颜色填充整个画布
// 随机产生155条干扰线,使图象中的认证码不易被其它程序探测到
g.setColor(getRandColor(160, 200));
for (int i = 0; i < 155; i++) {
int x = random.nextInt(60);
int y = random.nextInt(20);
int xl = random.nextInt(12);
int yl = random.nextInt(12);
g.drawLine(x, y, x + xl, y + yl);
}
//设定字体
g.setFont(new Font("Times New Roman", Font.PLAIN, 18));
String sRand="";
for (int i = 0; i < 4; i++) {
String rand = String.valueOf(random.nextInt(10));
sRand += rand;
// 将认证码显示到图象中
g.setColor(new Color(20 + random.nextInt(110), 20 + random.nextInt(110), 20 + random.nextInt(110)));
//调用函数出来的颜色相同,可能是因为种子太接近,所以只能直接生成
g.drawString(rand, 13 * i + 6, 16);
}
g.dispose();
// 输出图象到文件
// 把存在于内存的bit点阵(pixel),按JPEG格式压缩存盘
ImageIO.write(image, "JPEG", desc);
return sRand;
}
//给定范围获得随机颜色
private Color getRandColor(int fc, int bc) {
if (fc > 255)
fc = 255;
if (bc > 255)
bc = 255;
int r = fc + random.nextInt(bc - fc);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}
}