/***************************************************
 *  
 *  源文件名:  VerifyCode.java
 *  功    能： 夢想年華新聞系統 - 驗證碼
 *	作者：夢想年華 [DreamTime]
 *	Email:fanwsp@126.com
 *  QQ:122142023 
 * 	CopyRight(c)2005-2006 by DreamTime 
 *
 ****************************************************
*/


package dreamtime.dreamnews;			//指定類所在的包
import java.awt.*;						//導入類
import java.awt.image.*;
import java.util.*;
import javax.imageio.*;

//定義類

public class VerifyCode {
	static Random r = new Random();
	static String ssource = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"  + "abcdefghijklmnopqrstuvwxyz" + "0123456789";
	static char[] src = ssource.toCharArray();
	
	
	//產生隨機字符串
	
	private static String randString (int length){
		char[] buf = new char[length];
		int rnd;
		for(int i=0;i<length;i++){
			rnd = Math.abs(r.nextInt()) % src.length;
			
			buf[i] = src[rnd];
		}
		return new String(buf);
	}
	
	//調用該方法，產生隨機字符串,
	//參數i: 為字符串的長度
	public String runVerifyCode(int i){
		String VerifyCode = randString(i);
		return VerifyCode;
	}
	
	
	//給定范圍獲得隨機顏色
	public Color getRandColor(int fc,int bc)
	{
	   Random random = new Random();
	   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);
   	}
  
  	//調用該方法將得到的驗證碼生成圖象
  	//sCode:傳遞驗證碼 w:圖象寬度 h:圖象高度
  	public BufferedImage CreateImage(String sCode)
  	{
	  	try{	
	  		//字符的字體
			Font CodeFont = new Font("Arial Black",Font.PLAIN,16);
			int iLength = sCode.length();					//得到驗證碼長度
			int width=22*iLength, height=20;				//圖象寬度與高度
			int CharWidth = (int)(width-24)/iLength;		//字符距左邊寬度
			int CharHeight = 16;    						//字符距上邊高度
			
			// 在內存中創建圖象
			BufferedImage image = new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB);
			
			// 獲取圖形上下文
			Graphics g = image.getGraphics();
			
			//生成隨機類
			Random random = new Random();
			
			// 設定背景色
			g.setColor(getRandColor(200,240));
			g.fillRect(0, 0, width, height);
			
			//設定字體
			g.setFont(CodeFont);
			
			//畫隨機顏色的邊框
			g.setColor(getRandColor(10,50));
			g.drawRect(0,0,width-1,height-1);
			
			// 隨機產生155條干擾線，使圖象中的認證碼不易被其它程序探測到
			g.setColor(getRandColor(160,200));
			for (int i=0;i<155;i++)
			{
				  int x = random.nextInt(width);
				  int y = random.nextInt(height);
				  int xl = random.nextInt(12);
				  int yl = random.nextInt(12);
				  g.drawLine(x,y,x+xl,y+yl);
			}
			
	
			for (int i=0;i<iLength;i++)
			{
				String rand = sCode.substring(i,i+1); 
				// 將認證碼顯示到圖象中
				g.setColor(new Color(20+random.nextInt(60),20+random.nextInt(120),20+random.nextInt(180)));
				g.drawString(rand,CharWidth*i+14,CharHeight);
			}
			// 圖象生效
			g.dispose();
			return image;
		}catch(Exception e){
			//e.printStackTrace();	
			//System.out.println(e.getMessage());
			}
		return null;
	}
	
	//測試
	public static void main(String[] args){	
			//VerifyCode vc = new VerifyCode();
			//String s1 = vc.runVerifyCode(4);
			//Fun.DreamNewsTitle;System.out.println(s1);	
			//Image im = vc.CreateImage(s1);
			//Graphics g = im.getGraphics();
			//g.drawImage(im,20,20,this);
			//g.drawString(s1,20,20);
			
	}	
}