GDI+ 绘制验证码

小鱼儿 2021-10-15 02:45 267阅读 0赞

GDI绘制学习资料：[GDI绘制学习资料][GDI]

## 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);`  
    ![在这里插入图片描述][20190815161607550.png]

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;

[GDI]: https://blog.csdn.net/shenqiankk/article/details/99633134
[20190815161607550.png]: /images/20211015/2e23699b061141e0b9fe1685c91958ff.png