protected void Page_Load(object sender, EventArgs e)
{
System.Drawing.Image img = new Bitmap(200, 100);//画画布
Graphics g = Graphics.FromImage(img);//通过改变图像改变画布内容
// g.DrawString("hello", new Font("宋体", 12), Brushes.Gray, 0, 0);
this.AddPoint(img, 100);//画噪点
string code = this.GeneralCode();//随机生成数字
//加字体
Font font1 = new Font("宋体", 20, FontStyle.Italic);
g.DrawString(code, font1, Brushes.Red, 10, 10);
//输出
this.Response.Clear();//先清空
MemoryStream ms = new MemoryStream();//实例化一个流
img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);//保存这张图片
this.Response.BinaryWrite(ms.ToArray());//放到缓存区
this.Response.Flush();//显示
this.Response.End();//结束
}
private void AddPoint(System.Drawing.Image img, int nums)//给谁加加多少
{
Bitmap b = img as Bitmap;//声明个画布
Random ran = new Random();//随机生成点
for (int i = 0; i < nums; i++)
{
b.SetPixel(ran.Next(0, img.Width), ran.Next(0, img.Height),Color.White);//设置噪点的取值范围和颜色
}
}
//随机生成数字
private string GeneralCode()
{
Random ran = new Random(DateTime.Now.Millisecond);
StringBuilder sb = new StringBuilder(6);//位数
for (int i = 0; i < 6;i++ )
{
sb.Append(ran.Next(0, 9));
}
return sb.ToString();