服务器代码:
public void ProcessRequest(HttpContext context)
{
//context.Response.ContentType = "text/plain";
//context.Response.Write("Hello World");
Random rdn = new Random();
CreateValidateGraphic(rdn.Next(1000, 10000).ToString(), context);
}
/// <summary>
/// 创建验证码的图片
/// </summary>
public void CreateValidateGraphic(string validateCode, HttpContext context)
{
Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length*12.0),22);
Graphics g = Graphics.FromImage(image);
try
{
//生成随机生成器
Random random = new Random();
//清空图片背景色
g.Clear(Color.White);
//画图片的干扰线
for (int i = 0; i < 25; i++)
{
int x1 = random.Next(image.Width);
int x2 = random.Next(image.Width);
int y1 = random.Next(image.Height);
int y2 = random.Next(image.Height);
g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
}
Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));
System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkBlue, 1.2f, true);
g.DrawString(validateCode, font, brush, 3, 2);
//画图片的前景干扰点
for (int i = 0; i < 100; i++)
{
int x = random.Next(image.Width);
int y = random.Next(image.Height);
image.SetPixel(x, y, Color.FromArgb(random.Next()));
}
//画图片的边框线
g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
//保存图片的数据
MemoryStream stream = new MemoryStream();
image.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
//输出图片流
context.Response.Clear();
context.Response.ContentType = "image/Jpeg";
context.Response.BinaryWrite(stream.ToArray());
}
finally
{
g.Dispose();
image.Dispose();
}
}
HTML代码:
<script type="text/javascript">
window.onload = function () {
document.getElementById("aLink").onclick = function () {
//如果看不清，则重新请求一次一般处理程序,获取一张新图片即可
document.getElementById("img1").src = 'CreateCode.ashx?id='+Math.random();
return false;
};
};
</script>
<body>
<img src="CreateCode.ashx" id="img1" alt="1"/>
<a href="#" id="aLink">看不清?</a>
</body>
----以上是在asp.net网站中的应用，mvc版参考：http://www.cnblogs.com/shuai7boy/p/6195134.html