1 /**//// <summary>
  2    /// 验证码类
  3    /// </summary>
  4    public class ValidateImage
5    {
6        /**//// <summary>
  7        /// 要显示的文字
  8        /// </summary>
  9        public string Text
10        {
11            get { return this.text; }
12        }
13        /**//// <summary>
 14        /// 图片
 15        /// </summary>
 16        public Bitmap Image
17        {
18            get { return this.image; }
19        }
20        /**//// <summary>
 21        /// 宽度
 22        /// </summary>
 23        public int Width
24        {
25            get { return this.width; }
26        }
27        /**//// <summary>
 28        /// 高度
 29        /// </summary>
 30        public int Height
31        {
32            get { return this.height; }
33        }
34
35        private string text;
36        private int width;
37        private int height;
38        private Bitmap image;
39
40        private static byte[] randb = new byte[4];
41        private static Random rand = new Random();
42
43        public ValidateImage()
44        {
45            text = rand.Next(1000, 9999).ToString();
46            System.Web.HttpContext.Current.Session["CheckCode"] = text;
47            this.width = (int)Math.Ceiling(text.Length * 16.5);
48            this.height = 30;
49
50            GenerateImage();
51            System.Web.HttpContext.Current.Response.ContentType = "image/pjpeg";
52            Image.Save(System.Web.HttpContext.Current.Response.OutputStream, ImageFormat.Jpeg);
53
54        }
55
56        public static bool Validate(string input)
57        {
58            return System.Web.HttpContext.Current.Session["CheckCode"] != null && System.Web.HttpContext.Current.Session["CheckCode"].ToString().Equals(input);
59        }
60
61        ~ValidateImage()
62        {
63            Dispose(false);
64        }
65
66        public void Dispose()
67        {
68            GC.SuppressFinalize(this);
69            this.Dispose(true);
70        }
71
72        protected virtual void Dispose(bool disposing)
73        {
74            if (disposing)
75                this.image.Dispose();
76        }
77        private FontFamily[] fonts = {
78                                         new FontFamily("Times New Roman"),
79                                         new FontFamily("Georgia"),
80                                         new FontFamily("Arial"),
81                                         new FontFamily("Comic Sans MS")
82                                     };
83
84        public int Next(int max)
85        {
86            return rand.Next(max);
87        }
88
89        /**//// <summary>
 90        /// 生成验证码图片
 91
92        /// </summary>
 93        private void GenerateImage()
94        {
95            Bitmap bitmap = new Bitmap(this.width, this.height, PixelFormat.Format32bppArgb);
96
97            Graphics g = Graphics.FromImage(bitmap);
98            Rectangle rect = new Rectangle(0, 0, this.width, this.height);
99            g.SmoothingMode = SmoothingMode.AntiAlias;
100
101            g.Clear(Color.White);
102
103            //int emSize = Next(3) + 15;//(int)((this.width - 20) * 2 / text.Length);
104            //int emSize = (int)((this.width - 20) * 2 / text.Length);
105
106            int emSize = 12;
107            FontFamily family = fonts[Next(fonts.Length - 1)];
108            Font font = new Font(family, emSize, FontStyle.Bold);
109
110            SizeF measured = new SizeF(0, 0);
111            SizeF workingSize = new SizeF(this.width, this.height);
112            while (emSize > 2 && (measured = g.MeasureString(text, font)).Width > workingSize.Width || measured.Height > workingSize.Height)
113            {
114                font.Dispose();
115                font = new Font(family, emSize -= 2);
116            }
117
118            SolidBrush drawBrush = new SolidBrush(Color.FromArgb(Next(100), Next(80), Next(80)));
119            for (int x = 0; x < 1; x++)
120            {
121                Pen linePen = new Pen(Color.FromArgb(Next(150), Next(100), Next(100)), 1);
122                g.DrawLine(linePen, new PointF(0.0F + Next(2), 0.0F + Next(this.height)), new PointF(0.0F + Next(this.width), 0.0F + Next(this.height - 10)));
123            }
124
125            for (int x = 0; x < this.text.Length; x++)
126            {
127                drawBrush.Color = Color.FromArgb(Next(150) + 20, Next(150) + 20, Next(150) + 20);
128                PointF drawPoint = new PointF(0.0F + Next(5) + x * 15, 2.0F + Next(4));
129                g.DrawString(this.text[x].ToString(), font, drawBrush, drawPoint);
130            }
131
132            double distort = rand.Next(5, 10) * (Next(10) == 1 ? 1 : -1);
133
134            using (Bitmap copy = (Bitmap)bitmap.Clone())
135            {
136                for (int y = 0; y < height; y++)
137                {
138                    for (int x = 0; x < width; x++)
139                    {
140                        int newX = (int)(x + (distort * Math.Sin(Math.PI * y / 84.0)));
141                        int newY = (int)(y + (distort * Math.Cos(Math.PI * x / 54.0)));
142                        if (newX < 0 || newX >= width) newX = 0;
143                        if (newY < 0 || newY >= height) newY = 0;
144                        bitmap.SetPixel(x, y, copy.GetPixel(newX, newY));
145                    }
146                }
147            }
148
149
150            //g.DrawRectangle(new Pen(Color.Silver), 0, 0, bitmap.Width - 1, bitmap.Height - 1);
151
152            font.Dispose();
153            drawBrush.Dispose();
154            g.Dispose();
155
156            this.image = bitmap;
157        }
158    }