Asp.Net验证码3

using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
using System.IO;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Drawing.Text;

public partial class user_Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        CreateImage(GetCheckCode(VCODE_LENGTH));
    }

    protected static int VCODE_LENGTH = 4;

    //产生图片 宽度：_WIDTH, 高度：_HEIGHT
    private static readonly int _WIDTH = 80, _HEIGHT = 35;
    //字体集
    private static readonly string[] _FONT_FAMIly = { "Broadway", "Arial", "Arial Black", "Courier New", "Showcard Gothic", "Algerian", "Wide Latin", "Bernard MT Condensed", "Cooper Black" };
    //字体大小集
    private static readonly int[] _FONT_SIZE = { 16, 17, 18 };
    //前景字体颜色集
    private static readonly Color[] _COLOR_FACE = { Color.FromArgb(113, 153, 67), Color.FromArgb(30, 127, 182), Color.FromArgb(101, 44, 29), Color.FromArgb(150, 156, 0) };
    //背景颜色集
    private static readonly Color[] _COLOR_BACKGROUND = { Color.FromArgb(247, 254, 236), Color.FromArgb(234, 248, 255), Color.FromArgb(244, 250, 246), Color.FromArgb(248, 248, 248) };
    //文本布局信息
    private static StringFormat _DL_FORMAT = new StringFormat(StringFormatFlags.NoClip);
    //左右旋转角度
    private static readonly int _ANGLE = 60;

    private string GetCheckCode(int codeCount)
    {
        string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,W,X,Y,Z";
        string[] allCharArray = allChar.Split(',');
        string randomCode = "";
        int temp = -1;
        Random rand = new Random();
        for (int i = 0; i < codeCount; i++)
        {
            if (temp != -1)
            {
                rand = new Random(i * temp * ((int)DateTime.Now.Ticks));
            }
            int t = rand.Next(35);
            if (temp == t)
            {
                return GetCheckCode(codeCount);
            }
            temp = t;
            randomCode += allCharArray[t];
        }
        return randomCode;
    }

    private void CreateImage(string code)
    {
        _DL_FORMAT.Alignment = StringAlignment.Center;
        _DL_FORMAT.LineAlignment = StringAlignment.Center;

        long tick = DateTime.Now.Ticks;
        Random Rnd = new Random((int)(tick & 0xffffffffL) | (int)(tick >> 32));

        using (Bitmap _img = new Bitmap(_WIDTH, _HEIGHT))
        {
            using (Graphics g = Graphics.FromImage(_img))
            {
                g.TextRenderingHint = TextRenderingHint.ClearTypeGridFit;

                Point dot = new Point(18, 18);

                // 定义一个无干扰线区间和一个起始位置
                int nor = Rnd.Next(53), rsta = Rnd.Next(130);
                // 绘制干扰正弦曲线 M:曲线平折度, D:Y轴常量 V:X轴焦距
                int M = Rnd.Next(15) + 5, D = Rnd.Next(20) + 15, V = Rnd.Next(5) + 1;

                int ColorIndex = Rnd.Next(4);

                float Px_x = 0.0F;
                float Px_y = Convert.ToSingle(M * Math.Sin(V * Px_x * Math.PI / 180) + D);
                float Py_x, Py_y;

                //填充背景
                g.Clear(_COLOR_BACKGROUND[Rnd.Next(4)]);

                //前景刷子 //背景刷子
                using (Brush _BrushFace = new SolidBrush(_COLOR_FACE[ColorIndex]))
                {
                    #region 绘制正弦线
                    for (int i = 0; i < 131; i++)
                    {
                        //初始化y点
                        Py_x = Px_x + 1;
                        Py_y = Convert.ToSingle(M * Math.Sin(V * Py_x * Math.PI / 180) + D);

                        //确定线条颜色
                        if (rsta >= i || i > (rsta + nor))
                            //初始化画笔
                            using (Pen _pen = new Pen(_BrushFace, 1.5f))
                            {
                                //绘制线条
                                g.DrawLine(_pen, Px_x, Px_y, Py_x, Py_y);
                            }

                        //交替x,y坐标点
                        Px_x = Py_x;
                        Px_y = Py_y;
                    }
                    #endregion

                    //初始化光标的开始位置
                    g.TranslateTransform(-5, 2);

                    #region 绘制校验码字符串
                    for (int i = 0; i < code.Length; i++)
                    {
                        //随机旋转 角度
                        int angle = Rnd.Next(-_ANGLE, _ANGLE);
                        //移动光标到指定位置
                        g.TranslateTransform(dot.X, dot.Y);
                        //旋转
                        g.RotateTransform(angle);

                        //初始化字体
                        using (Font _font = new Font(_FONT_FAMIly[Rnd.Next(0, 8)], _FONT_SIZE[Rnd.Next(0, 3)]))
                        {
                            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, _WIDTH, _HEIGHT), _COLOR_FACE[ColorIndex], Color.Orange, 1.2f, true);

                            //绘制
                            g.DrawString(code[i].ToString(), _font, brush, 1, 1, _DL_FORMAT);
                        }
                        //反转
                        g.RotateTransform(-angle);
                        //重新定位光标位置
                        g.TranslateTransform(-2, -dot.Y);
                    }
                    #endregion

                }
            }

            using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
            {
                Response.ContentType = "Image/PNG";
                Response.Clear();
                Response.BufferOutput = true;
                _img.Save(ms, ImageFormat.Png);
                ms.Flush();
                Response.BinaryWrite(ms.GetBuffer());
                Response.End();
            }
        }

    }
}

验证码效果：

还有2种验证码：

http://www.cnblogs.com/webapi/p/5725576.html

http://www.cnblogs.com/webapi/p/5726489.html