Php random verification code image generation instance details

Php random verification code image generation instance details

/** Default homepage **/ Class DefaultController extends AppController { Public function index (){ $ Len = 5; $ Str = "ABCDEFGHIJKLNMPQRSTUVWXYZ123456789 "; $ Im = imagecreatetruecolor (70, 20 ); $ Bgc = imagecolorallocate ($ im, 255,255,255 ); $ Bgtxt = imagecolorallocate ($ im, 220,220,220 ); // Random color palette $ Colors = array ( Imagecolorallocate ($ im, 255, 0, 0 ), Imagecolorallocate ($ im, 0,200, 0 ), Imagecolorallocate ($ im, 0, 0,255 ), Imagecolorallocate ($ im, 0, 0, 0 ), Imagecolorallocate ($ im, 255,128, 0 ), Imagecolorallocate ($ im, 255,208, 0 ), Imagecolorallocate ($ im, 98,186,245 ), ); // Fill in the background color Imagefill ($ im, 0, 0, $ bgc ); // Obtain random numbers $ Verify = ""; While (strlen ($ verify) <$ len ){ $ I = strlen ($ verify ); $ Random = $ str [rand (0, strlen ($ str)]; $ Verify. = $ random; // Draw background text Imagestring ($ im, 6, ($ I * 10) + 3, rand (0, 6), $ random, $ bgtxt ); // Draw the main text information Imagestring ($ im, 6, ($ I * 10) + 3, rand (0, 6), $ random, $ colors [rand (0, count ($ colors) -1)]); } // Add random colors For ($ I = 0; I I <100; $ I ++ ){ $ Color = imagecolorallocate ($ im, rand (50,220), rand (50,220), rand (50,220 )); Imagesetpixel ($ im, rand (0, 70), rand (0, 20), $ color ); } // Save the verification code to $ _ SESSION Sess ("verify", $ verify ); // Output the image and release the cache Header ('content-type: image/png '); Imagepng ($ im ); Imagedestroy ($ im ); } }; ?> Example 2: a php instance that generates a random string and verification code class. The implementation of the following code can distinguish one get_code () and the other create_check_image (). the output image is called directly after the session () command, and get_code () is used to obtain the verification code. When using session, you must put session_star () at the beginning. Complete code: Class RandCheckCode { /* Function name: get_code () * Function: obtain a random string. * Parameters: 1. (int) $ length = 32 # random character length 2. (int) $ mode = 0 # random character type, 0 is a combination of uppercase and lowercase English letters and numbers, 1 is a number, 2 is a lowercase letter, 3 is a capital letter, 4: uppercase letters, 5: uppercase letters and numbers, 6: lowercase letters and numbers * Return: the obtained string. */ Function get_code ($ length = 32, $ mode = 0) // Obtain the random verification code function { Switch ($ mode) { Case '1 ': $ Str = '000000 '; Break; Case '2 ': $ Str = 'abcdefghijklmnopqrstuvwxy '; Break; Case '3 ': $ Str = 'abcdefghijklmnopqrstuvwxy '; Break; Case '4 ': $ Str = 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxy '; Break; Case '5 ': $ Str = 'abcdefghijklmnopqrstuvwxyz1234567890 '; Break; Case '6 ': $ Str = 'abcdefghijklmnopqrstuvwxyz1234567890 '; Break; Default: $ Str = 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz1234567890 '; Break; } $ Checkstr = ''; $ Len = strlen ($ str)-1; For ($ I = 0; $ I <$ length; $ I ++) { // $ Num = rand (0, $ len); // generates a random number between 0 and $ len. $ Num = mt_rand (0, $ len); // generates a random number between 0 and $ len. $ Checkstr. = $ str [$ num]; } Return $ checkstr; } /** Function name: create_check_image () Function: generates an image of the verification code. Parameter: $ checkcode: verification code string Return value: returns the image. */ Function create_check_image ($ checkcode) // Generate { $ Im = imagecreate (); // generate an image $ Black = imagecolorallocate ($ im, 0, 0); // background color $ White = imagecolorallocate ($ im, 255,255,255); // foreground color $ Gray = imagecolorallocate ($ im, 200,200,200 ); Imagefill ($ im, 30, 30, $ gray); // The coordinates of the $ im image are 30, 30 (the upper left corner of the image is 0, 0) fill the area with the $ gray color (that is, the adjacent points will be filled with the same color as the 30, 30 points) Imagestring ($ im, 5, 8, 3, $ checkcode, $ white ); // use the $ white color to draw the string $ checkcode to the 8, 3 coordinates of the image represented by $ im (this is the coordinate of the upper left corner of the string, the upper left corner of the entire image is 0, 0), and 5 is the font size, the font can only be 1, 2, 3, 4, or 5. the built-in font is used. For ($ I = 0; I I <120; $ I ++) { $ Randcolor = imagecolorallocate ($ im, rand (0,255), rand (0,255), rand (0,255 )); Imagesetpixel ($ im, rand () % 70, rand () % 30, $ randcolor); // use $ randcolor on $ im images at (rand () % 70, rand () % 30) coordinate (the upper left corner of the image is 0, 0 ). } Header ("Content-type: image/png "); Imagepng ($ im); // output the image to a browser or file in PNG format Imagedestroy ($ im); // destroy the image $ im } } /* $ Randcode = new RandCheckCode (); $ Checkstring = $ randcode-> get_code (5, 7 ); $ Image = $ randcode-> create_check_image ($ checkstring ); Echo $ image; */ ?>