下面代码文件名是ValidateCode.ashx
public class ValidateCode : IHttpHandler, IRequiresSessionState
{
/// <summary>
/// 验证码|使用事例：<img src="../tools/ValidateCode.ashx" onclick="this.src='../tools/ValidateCode.ashx'"alt="看不清验证码,请单击" style="cursor: hand; width: 52px; height: 18px;" />
/// </summary>
/// <param name="context"></param>
public void ProcessRequest(HttpContext context)
{
context.Response.Cache.SetCacheability(HttpCacheability.NoCache);
context.Response.ContentType = "text/plain";
int w = Common.CFun.GetQueryInt("w", HttpContext.Current);
w = w > 0 ? w : 63;
int h = Common.CFun.GetQueryInt("h", HttpContext.Current);
h = h > 0 ? h : 30;
string checkCode = GenerateCheckCode();
context.Session["CheckCode"] = checkCode;//将验证码写入Session
Bitmap image = CreateCheckCodeImage(checkCode, w, h);
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
context.Response.ClearContent();
context.Response.ContentType = "image/Gif";
context.Response.BinaryWrite(ms.ToArray());
}
/// <summary>
/// 得到验证码
/// </summary>
/// <param name="context"></param>
/// <returns></returns>
private string GenerateCheckCode()
{
int number;
char code;
string checkCode = String.Empty;
System.Random random = new Random();
for (int i = 0; i < 4; i++)
{
number = random.Next();
if (number % 2 == 0)
code = (char)('0' + (char)(number % 10));
else if (number % 3 == 0)
code = (char)('A' + (char)(number % 26));
else
code = (char)('a' + (char)(number % 26));
checkCode += code.ToString();
}
return checkCode.ToUpper();
}
/// <summary>
/// 生成验证码图片
/// </summary>
/// <param name="checkCode"></param>
/// <param name="context"></param>
private Bitmap CreateCheckCodeImage(string checkCode, int w = 54, int h = 30)
{
System.Drawing.Bitmap image = new System.Drawing.Bitmap(w, h);
Graphics g = Graphics.FromImage(image);
g.Clear(Color.WhiteSmoke);//清除背景色
Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };//定义随机颜色
string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };
Random rand = new Random();
int z = 0;//干扰线条数
for (int i = 0; i < z; i++)
{
int x1 = rand.Next(image.Width);
int x2 = rand.Next(image.Width);
int y1 = rand.Next(image.Height);
int y2 = rand.Next(image.Height);
g.DrawLine(new Pen(Color.LightGray, 1), x1, y1, x2, y2);//根据坐标画线
}
for (int i = 0; i < checkCode.Length; i++)
{
int cindex = rand.Next(7);
int findex = rand.Next(5);
Font f = new System.Drawing.Font(font[findex], 14, System.Drawing.FontStyle.Bold);
Brush b = new System.Drawing.SolidBrush(c[cindex]);
int ii = 4;
if ((i + 1) % 2 == 0)
{
ii = 2;
}
g.DrawString(checkCode.Substring(i, 1), f, b, 3 + (i * (14)), ii);
}
image = TwistImage(image, true, 5, 1);
g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1);
return image;
}
#region 产生波形滤镜效果
private const double PI = 3.1415926535897932384626433832795;
private const double PI2 = 6.283185307179586476925286766559;
/// <summary>
/// 正弦曲线Wave扭曲图片（Edit By 51aspx.com）
/// </summary>
/// <param name="srcBmp">图片路径</param>
/// <param name="bXDir">如果扭曲则选择为True</param>
/// <param name="nMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</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(nOldX, nOldY, color);
}
}
}
return destBmp;
}
#endregion
public bool IsReusable
{
get
{
return false;
}
}
}
以下调用方法
<span class="ckcinput"> <img id="checkCodeImg" src="/ValidateCode.ashx" align="absmiddle" onclick="changeCC()"alt="看不清验证码,请单击" style="cursor: pointer; width: 56px; height: 30px; margin-top: 5px;margin-left: 2px;" /> </span>
JS代码方法
function changeCC() {
$("#checkCodeImg").attr("src", "/ValidateCode.ashx?" + Math.random());
}