using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
namespace Utility
{
/// <summary>
/// 完美随机验证码 0.10
/// Verion:0.10
/// Description:随机生成设定验证码，并随机旋转一定角度，字体颜色不同
/// </summary>
public class ValidateCode
{
/// <summary>
/// 生成随机码
/// </summary>
/// <param >随机码个数</param>
/// <returns></returns>
public static string CreateRandomCode(int length)
{
int rand;
char code;
string randomcode = String.Empty;
//生成一定长度的验证码
System.Random random = new Random();
for (int i = 0; i < length; i++)
{
rand = random.Next();
if (rand % 3 == 0)
{
code = (char)('A' + (char)(rand % 26));
}
else
{
code = (char)('0' + (char)(rand % 10));
}
randomcode += code.ToString();
}
return randomcode;
}
/// <summary>
/// 创建随机码图片
/// </summary>
/// <param >随机码</param>
public static void CreateImage(string randomcode)
{
int randAngle = 45; //随机转动角度
int mapwidth = (int)(randomcode.Length * 23);
Bitmap map = new Bitmap(mapwidth, 28);//创建图片背景
Graphics graph = Graphics.FromImage(map);
graph.Clear(Color.AliceBlue);//清除画面，填充背景
graph.DrawRectangle(new Pen(Color.Black, 0), 0, 0, map.Width - 1, map.Height - 1);//画一个边框
//graph.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;//模式
Random rand = new Random();
//背景噪点生成
Pen blackPen = new Pen(Color.LightGray, 0);
for (int i = 0; i < 50; i++)
{
int x = rand.Next(0, map.Width);
int y = rand.Next(0, map.Height);
graph.DrawRectangle(blackPen, x, y, 1, 1);
}
//验证码旋转，防止机器识别
char[] chars = randomcode.ToCharArray();//拆散字符串成单字符数组
//文字距中
StringFormat format = new StringFormat(StringFormatFlags.NoClip);
format.Alignment = StringAlignment.Center;
format.LineAlignment = StringAlignment.Center;
//定义颜色
Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
//定义字体
string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };
for (int i = 0; i < chars.Length; i++)
{
int cindex = rand.Next(7);
int findex = rand.Next(5);
Font f = new System.Drawing.Font(font[findex], 13, System.Drawing.FontStyle.Bold);//字体样式(参数2为字体大小)
Brush b = new System.Drawing.SolidBrush(c[cindex]);
Point dot = new Point(16, 16);
//graph.DrawString(dot.X.ToString(),fontstyle,new SolidBrush(Color.Black),10,150);//测试X坐标显示间距的
float angle = rand.Next(-randAngle, randAngle);//转动的度数
graph.TranslateTransform(dot.X, dot.Y);//移动光标到指定位置
graph.RotateTransform(angle);
graph.DrawString(chars.ToString(), f, b, 1, 1, format);
//graph.DrawString(chars.ToString(),fontstyle,new SolidBrush(Color.Blue),1,1,format);
graph.RotateTransform(-angle);//转回去
graph.TranslateTransform(2, -dot.Y);//移动光标到指定位置
}
//graph.DrawString(randomcode,fontstyle,new SolidBrush(Color.Blue),2,2); //标准随机码
//生成图片
System.IO.MemoryStream ms = new System.IO.MemoryStream();
map.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
HttpContext.Current.Response.ClearContent();
HttpContext.Current.Response.ContentType = "image/gif";
HttpContext.Current.Response.BinaryWrite(ms.ToArray());
graph.Dispose();
map.Dispose();
}
}
}