学习笔记：利用GDI+生成简单的验证码图片

学习笔记：利用GDI+生成简单的验证码图片

 /// <summary>
         /// 单击图片时切换图片
         /// </summary>
         /// <param name="sender"></param>
         /// <param name="e"></param>
         private void pictureBox1_Click(object sender, EventArgs e)
         {
             Random r = new Random();
             string str = string.Empty;
             //生成5位随机数如 90531
             for (int i = ; i < ; i++)
             {
                 str += r.Next(, );
             }
             Bitmap bitmap = new Bitmap(, );
             Graphics g = Graphics.FromImage(bitmap);
             //预定义几种字体样式和颜色
             string[] fonts = { "微软雅黑", "宋体", "黑体", "隶书", "仿宋" };
             Color[] colors = { Color.Yellow, Color.Blue, Color.Black, Color.Red, Color.Orange };
             //因为每一数字的字体和颜色可能不同，
             //因此循环将生成的随机数每一数字绘制到图片
             for (int i = ; i < str.Length; i++)
             {
                 Point p = new Point(i * , );
                 g.DrawString(str[i].ToString(), new Font(fonts[r.Next(, )], , FontStyle.Bold), new SolidBrush(colors[r.Next(, )]), p);
             }
             //循环在图片范围内绘制出50条线
             for (int i = ; i < ; i++)
             {
                 //保证线的起始点都在图片范围内
                 Point p1 = new Point(r.Next(, bitmap.Width), r.Next(, bitmap.Height));
                 Point p2 = new Point(r.Next(, bitmap.Width), r.Next(, bitmap.Height));
                 g.DrawLine(new Pen(Brushes.Green), p1, p2);
             }
             //添加一些像素点
             for (int i = ; i < ; i++)
             {
                 Point p1 = new Point(r.Next(, bitmap.Width), r.Next(, bitmap.Height));
                 bitmap.SetPixel(p1.X, p1.Y, Color.Green);
             }
             //在winForm中用PictureBox中显示出来
             pictureBox1.Image = bitmap;
         }

最终效果如下