C# GDI繪製驗證碼

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步驟:1.通過Random產生隨機數或字元及驗證碼2.通過驗證碼內容長度產生指定大小的圖片3.擷取產生圖片的Graphics對象4.定義驗證碼字型格式5.通過指定字型將驗證碼繪製到圖片6.向圖片上添加背景雜音線7.添加前景噪音點 

 1  private void pictureBox1_Click(object sender, EventArgs e) 2         { 3             Random r = new Random(); 4             string str = null; 5             for (int i = 0; i < 5; i++) 6             { 7                 int rNumber = r.Next(0, 10); 8                 str += rNumber; 9             }10             //MessageBox.Show(str);11             //建立GDI對象12             Bitmap bmp=new Bitmap(120,50);13             Graphics g = Graphics.FromImage(bmp);14 15             for (int i = 0; i < 5; i++)16             {17                 Point p=new Point(i*20,0);18                 string [] fonts={"微軟雅黑","宋體","黑體","隸書","仿宋"};19                 Color [] colors={Color.Yellow,Color.Blue,Color.Black,Color.Red,Color.Green};20                 g.DrawString(str[i].ToString(),new Font(fonts[r.Next(0,4)],20,FontStyle.Bold),new SolidBrush(colors[r.Next(0,5)]),p);21             }22             //繪製線條,線條不能超出驗證碼的範圍23             for (int i = 0; i < 30; i++)24             {25                 Point p1=new Point(r.Next(0,bmp.Width),r.Next(0,bmp.Height));26                 Point p2=new Point(r.Next(0,bmp.Width),r.Next(0,bmp.Height));27                 g.DrawLine(new Pen(Brushes.Green), p1, p2);28             }29 30             for (int i = 0; i < 1000; i++)31             {32                 Point p=new Point(r.Next(0,bmp.Width),r.Next(0,bmp.Height));33                 bmp.SetPixel(p.X, p.Y, Color.Black);34             }35             //將圖片鑲嵌到PictureBox中36             pictureBox1.Image = bmp;37 38         }

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C# GDI繪製驗證碼