学习笔记：利用GDI+生成简略的验证码图片

 1 /// <summary> 2         /// 单击图片时切换图片 3         /// </summary> 4         /// <param name="sender"></param> 5         /// <param name="e"></param> 6         private void pictureBox1_Click(object sender, EventArgs e) 7         { 8             Random r = new Random(); 9             string str = string.Empty;10             //生成5位随机数如 9053111             for (int i = 0; i < 5; i++)12             {13                 str += r.Next(0, 10);14             }15             Bitmap bitmap = new Bitmap(150, 40);16             Graphics g = Graphics.FromImage(bitmap);17             //预定义几种字体样式和颜色18             string[] fonts = { "微软雅黑", "宋体", "黑体", "隶书", "仿宋" };19             Color[] colors = { Color.Yellow, Color.Blue, Color.Black, Color.Red, Color.Orange };20             //因为每一数字的字体和颜色可能不同，21             //因此循环将生成的随机数每一数字绘制到图片22             for (int i = 0; i < str.Length; i++)23             {24                 Point p = new Point(i * 30, 0);25                 g.DrawString(str[i].ToString(), new Font(fonts[r.Next(0, 5)], 20, FontStyle.Bold), new SolidBrush(colors[r.Next(0, 5)]), p);26             }27             //循环在图片范围内绘制出50条线28             for (int i = 0; i < 50; i++)29             {30                 //保证线的起始点都在图片范围内31                 Point p1 = new Point(r.Next(0, bitmap.Width), r.Next(0, bitmap.Height));32                 Point p2 = new Point(r.Next(0, bitmap.Width), r.Next(0, bitmap.Height));33                 g.DrawLine(new Pen(Brushes.Green), p1, p2);34             }35             //添加一些像素点36             for (int i = 0; i < 300; i++)37             {38                 Point p1 = new Point(r.Next(0, bitmap.Width), r.Next(0, bitmap.Height));39                 bitmap.SetPixel(p1.X, p1.Y, Color.Green);40             }41             //在winForm中用PictureBox中显示出来42             pictureBox1.Image = bitmap;43         }