Dynamic Verification Code Generation

Knowledge point:

1. Operations on Images

 

Problem:

Dynamic Verification Code Generation

 

Solution

1 <% @ webhandler Language = "C #" class = "validatecode" %> 2 3 using system; 4 using system. web; 5 using system. drawing; 6 using system. io; 7 8 public class validatecode: ihttphandler {9 10 public void processrequest (httpcontext context) {11 context. response. contenttype = "text/plain"; 12 // context. response. write ("Hello World"); 13 random r = new random (); 14 int n = R. next (values, 100000); 15 createvalidategraphic (N. tostring (), context ); 16} 17 /// <summary> 18 // picture of the Verification Code created 19 /// </Summary> 20 /// <Param name = "containspage"> to output page Object </param> 21 // <Param name = "validatenum"> Verification Code </param> 22 public void createvalidategraphic (string validatecode, httpcontext context) 23 {24 bitmap image = new Bitmap (INT) math. ceiling (validatecode. length * 12.0), 22); 25 graphics G = graphics. fromimage (image); 26 try27 {28 // generate random generator 29 random = new random (); 30 // clear the image background color 31G. clear (color. white); 32 // The interference line of the picture. 33 for (INT I = 0; I <25; I ++) 34 {35 int X1 = random. next (image. width); 36 int X2 = random. next (image. width); 37 int Y1 = random. next (image. height); 38 int y2 = random. next (image. height); 39G. drawline (new pen (color. silver), X1, Y1, X2, Y2); 40} 41 Font font = new font ("Arial", 12, (fontstyle. bold | fontstyle. italic); 42 system. drawing. drawing2d. lineargradientbrush brush = new system. drawing. drawing2d. lineargradientbrush (New rectangle (0, 0, image. width, image. height), 43 color. blue, color. darkred, 1.2f, true); 44G. drawstring (validatecode, Font, brush, 3, 2); 45 // foreground disturbance of the picture: 46 for (INT I = 0; I <100; I ++) 47 {48 int x = random. next (image. width); 49 int y = random. next (image. height); 50 image. setpixel (X, Y, color. fromargb (random. next (); 51} 52 // draw the border line of the image 53g. drawrectangle (new pen (color. silver), 0, 0, image. width-1, image. height-1); 54 // Save image data 55 memorystream stream = new memorystream (); 56 image. save (stream, system. drawing. imaging. imageformat. JPEG); 57 // output image stream 58 Context. response. clear (); 59 context. response. contenttype = "image/JPEG"; 60 context. response. binarywrite (stream. toarray (); 61} 62 finally63 {64g. dispose (); 65 image. dispose (); 66} 67} 68 69 public bool isreusable {70 get {71 return false; 72} 73} 74 75}

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Dynamic Verification Code Generation