Biegral Blog

  private void CreateImage(string codes)
        {
            try
            {
                int iMapWidth = codes.Length * 21;
                Bitmap map = new Bitmap(iMapWidth, 28);     //创建图片背景

                Graphics graph = Graphics.FromImage(map);
                graph.Clear(Color.AliceBlue);//清除画面，填充背景
                graph.DrawRectangle(new Pen(Color.Black, 0), 0, 0, map.Width - 1, map.Height - 1);//画一个边框
                graph.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;//模式 抗锯齿

                Random rand = new Random();

                //背景噪点生成
                Pen blackPen = new Pen(Color.LightGray, 0);
                for (int i = 0; i < 50; i++)
                {
                    int x = rand.Next(0, map.Width);
                    int y = rand.Next(0, map.Height);
                    graph.DrawRectangle(blackPen, x, y, 1, 1);
                }

                //验证码旋转，防止机器识别
                char[] chars = codes.ToCharArray();//拆散字符串成单字符数组

                //文字距中
                StringFormat format = new StringFormat(StringFormatFlags.NoClip);
                format.Alignment = StringAlignment.Center;
                format.LineAlignment = StringAlignment.Center;

                //定义颜色
                Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
                
                //定义字体
                string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };

                for (int i = 0; i < chars.Length; i++)
                {
                    int cindex = rand.Next(7);
                    int findex = rand.Next(5);

                    Font f = new System.Drawing.Font(font[findex], 13, System.Drawing.FontStyle.Bold);//字体样式(参数2为字体大小)
                    
                    Brush b = new System.Drawing.SolidBrush(c[cindex]);
      
                    graph.DrawString(chars[i].ToString(), f, b, i*16+8, 15, format);

                }

                this.pictureBox1.Image = map;


            }
            catch (ArgumentException ex)
            {
                MessageBox.Show("创建图片验证码错误，错误原因："+ex.Message.ToString());
            }
        }

        /// <summary>
        /// 得到单个字符
        /// </summary>
        /// <param name="a"></param>
        /// <param name="b"></param>
        /// <returns></returns>
        private string getOneCode(int a, int b)
        {
            char c = (char)ran.Next(a, b);
            return c.ToString();
        }

        /// <summary>
        /// 得到验证码
        /// </summary>
        /// <returns></returns>
        private string getCode()
        {
            string code = "";
            //Ascii码范围：数字:48-57，小写字母:97-122，大写字母:65-90  
            code += getOneCode(48,57);
            code += getOneCode(97, 122);
            code += getOneCode(65, 90);
            code += getOneCode(97, 122);
            code += getOneCode(48, 57);
            return code;
        }

        /// <summary>
        /// 加载验证码
        /// </summary>
        private void LoadCode()
        {
            string right_code = getCode();
            CreateImage(right_code);
        }