生成随机数图片

生成验证码图片

(2) 生成随机数图片

生成随机数图片

/// <summary>
/// 生成随机数图片
/// </summary>
/// <param name="codeCount">生成随机数的位数</param>
/// <returns>返回随机数</returns>
public static string CreateRandomCode(int codeCount)
{
    string allChar = "0,1,2,3,4,5,6,7,8,9" ;
    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(10);
        if(temp == t)
        {
            return CreateRandomCode(codeCount);
        }
        temp = t;
        randomCode += allCharArray[t];
    }
    return randomCode;
}

正弦曲线Wave扭曲图片

/// <summary>
/// 正弦曲线Wave扭曲图片
/// </summary>
/// <param name="srcBmp"></param>
/// <param name="bXDir"></param>
/// <param name="nMultValue">波形的幅度倍数</param>
/// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>
/// <returns></returns>
public System.Drawing.Bitmap TwistImage(Bitmap srcBmp,bool bXDir,double dMultValue,double dPhase)
{
    System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width,srcBmp.Height);

    // 将位图背景填充为白色
    System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);
    graph.FillRectangle(new SolidBrush(System.Drawing.Color.White),0,0,destBmp.Width,destBmp.Height);
    graph.Dispose();
  
    double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;

    for(int i=0;i<destBmp.Width;i++)
    {
        for(int j=0;j<destBmp.Height;j++)
        {
            double dx = 0;
            dx = bXDir ? (PI2*(double)j)/dBaseAxisLen : (PI2*(double)i)/dBaseAxisLen;
            dx += dPhase;
            double dy = Math.Sin(dx);

            // 取得当前点的颜色
            int nOldX = 0,nOldY = 0;
            nOldX = bXDir ? i + (int)(dy*dMultValue) : i;
            nOldY = bXDir ? j : j + (int)(dy*dMultValue);

            System.Drawing.Color color = srcBmp.GetPixel(i,j);
            if(nOldX >= 0 && nOldX < destBmp.Width
             && nOldY >=0 && nOldY < destBmp.Height)
            {
                destBmp.SetPixel(x, y, Color.FromArgb(rand.Next()));
            }
        }
    }
    return destBmp;
}

生成验证码图片

/// <summary>
/// 生成验证码图片
/// </summary>
/// <param name="checkCode"></param>
public static void CreateImage(string checkCode)
{
    int iwidth = (int)(checkCode.Length * 12);
    System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 25);
    Graphics g = Graphics.FromImage(image);
    Font f = new System.Drawing.Font("Arial", 12, System.Drawing.FontStyle.Bold);
   
    Brush b = new System.Drawing.SolidBrush(Color.FromArgb(51,51,51));
    //g.FillRectangle(new System.Drawing.SolidBrush(Color.Blue),0,0,image.Width, image.Height);
    g.Clear(Color.FromArgb(187,241,0));
    g.DrawString(checkCode, f, b, 3, 3);

    Pen blackPen = new Pen(Color.White, 0);
    Random rand = new Random();
//   for (int i=0;i<1;i++)
//   {
//    int y = rand.Next(image.Height);
//    g.DrawLine(blackPen,0,y,image.Width,image.Height);
//   }
//   //画图片的前景噪音点
    for(int i=0; i<30; i++)
    {
        int x = rand.Next(image.Width);
        int y = rand.Next(image.Height);

        image.SetPixel(x, y, Color.FromArgb(rand.Next()));
    }
    System.IO.MemoryStream ms = new System.IO.MemoryStream();
   
    image.Save(ms,System.Drawing.Imaging.ImageFormat.Jpeg);
    //System.Web.HttpContext.Current.Response.ClearContent();
    //System.Web.HttpContext.Current.Response.ContentType = "image/Jpeg";
    //System.Web.HttpContext.Current.Response.BinaryWrite(ms.ToArray());
    g.Dispose();
    image.Dispose();
}