GDI+ 绘制验证码

GDI绘制学习资料：GDI绘制学习资料

GDI绘制验证码

1. 创建5个随机数，存入字符串或者数组
2. 创建图形对象：Bitmap bmp = new Bitmap(150,40);
3. 创建GDI对象：Graphics g = Graphics.FromImage(bmp);
4. 循环5次，随机字体、颜色文本绘制每个随机数：
   g.DrawString(s[i].ToString(), new Font(fonts[r.Next(0, 5)], 20, FontStyle.Bold), new SolidBrush(colors[r.Next(0, 5)]),
5. 循环随机两点绘制直线，来做验证码的干扰线：g.DrawLine(new Pen(Brushes.Green), p1, p2);
6. 循环设置随机点的像素颜色：bmp.SetPixel(p.X, p.Y, Color.Black);
   

			Random r = new Random();
            string s = null;
            //创建5个随机数
            for (int i = 0; i < 5; i++)
            {
                int n = r.Next(0, 10);
                s += n;
            }
            //MessageBox.Show(s);

            //创建图形对象
            Bitmap bmp = new Bitmap(150,40);
            //创建GDI对象
            Graphics g = Graphics.FromImage(bmp);

            for(int i = 0; i < 5; i++)
            {
                //固定每个验证码的横坐标位置
                Point p = new Point(i * 20, 0);
                //创建字体和颜色数组
                string[] fonts = { "微软雅黑", "宋体", "黑体", "楷体", "仿宋" };
                Color[] colors = { Color.Yellow, Color.Blue, Color.Red, Color.Green, Color.Black };
                //绘制文本
                g.DrawString(s[i].ToString(), new Font(fonts[r.Next(0, 5)], 20, FontStyle.Bold), new SolidBrush(colors[r.Next(0, 5)]), p);
            }
            //循环多次绘制验证码干扰线条
            for(int i = 0; i < 20; i++)
            {
                //随机两个点的位置
                Point p1 = new Point(r.Next(0, bmp.Width), r.Next(0, bmp.Height));
                Point p2 = new Point(r.Next(0, bmp.Width), r.Next(0, bmp.Height));
                //绘制直线
                g.DrawLine(new Pen(Brushes.Green), p1, p2);
            }
            //循环多次绘制验证码的干扰像素点
            for(int i = 0; i < 500; i++)
            {
                //随机一个点的位置
                Point p = new Point(r.Next(0, bmp.Width), r.Next(0, bmp.Height));
                //设置图形指定位置的像素颜色
                bmp.SetPixel(p.X, p.Y, Color.Black);
            }
            //将图形嵌入到pictrueBox
            pictureBox1.Image = bmp;