PHP Random Verification Code Image generation example detailed

/** Default Home **/ 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 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 background color Imagefill ($im, 0, 0, $BGC); Get numbers randomly $verify = ""; while (strlen ($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, $bgtxt); Draw Main text information Imagestring ($im, 6, ($i *10) +3, rand (0,6), $random, $colors [rand (0, COUNT ($colors)-1)]); } Add Random noise for ($i =0; $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 verification Code in $_session Sess ("verify", $verify); Output a picture and release the cache Header (' content-type:image/png '); Imagepng ($im); Imagedestroy ($im); } }; ?> Copy Code Example 2, a class that generates a random string and a validation code for a class of random strings and Authenticode. The following code implementation, the main do can be very good to distinguish between a get_code (), another create_check_image (), the output image directly after the call, session () to take the verification code directly Get_code (). Session_star () must be placed at the front when using the session. Full code: Class Randcheckcode { /* Function Name: Get_code () * Function: Get random string Parameters 1, (int) $length = #随机字符长度 2, (int) $mode = 0 #随机字符类型, 0 for case English and numbers, 1 for numbers, 2 for lowercase letters, 3 for uppercase letters, 4 is uppercase and lowercase, 5 is capital letter and number, 6 is lowercase and number * Return: The obtained string */ function Get_code ($length =32, $mode =0)//Get random verification code functions { Switch ($mode) { Case ' 1 ': $str = ' 123456789 '; Break Case ' 2 ': $str = ' abcdefghijklmnopqrstuvwxyz '; Break Case ' 3 ': $str = ' abcdefghijklmnopqrstuvwxyz '; Break Case ' 4 ': $str = ' abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz '; 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);//Generate a random number between 0 and $len $num =mt_rand (0, $len);//Generate a random number between 0 and $len $checkstr. = $str [$num]; } return $checkstr; } /** function Name: Create_check_image () Function: Produces a picture of a checksum code Parameter: $checkcode: Check code string Return value: Returns the picture */ function Create_check_image ($checkcode)//produce a { $im =imagecreate (65,22);//produce a picture $black =imagecolorallocate ($im, 0,0,0);//Background color $white =imagecolorallocate ($im, 255,255,255);//Foreground color $gray =imagecolorallocate ($im, 200,200,200); Imagefill ($im, 30,30, $gray);//In the $im image coordinates 30,30 (the upper left corner of the image is 0,0) with the $gray color to perform the area fill (that is, with 30, 30 points of the same color and adjacent points will be filled) Imagestring ($im, 5,8,3, $checkcode, $white);//Use $white color to draw the string $checkcode to 8, 3 coordinates of the image represented by $im (this is the upper-left corner of the string, the upper-left corner of the image is 0,0), 5 is the font size, the font can only be 1,2,3,4 or 5, using the built-in font for ($i =0; $i <120; $i + +) { $randcolor =imagecolorallocate ($im, Rand (0,255), Rand (0,255), Rand (0,255)); Imagesetpixel ($im, Rand ()%70,rand ()%30, $randcolor),///on $im image with $randcolor color in (rand ()%70,rand ()%30) coordinates (the upper left corner of the image is 0,0) Draw a dot on the } Header ("Content-type:image/png"); Imagepng ($im);//Export the image to a browser or file in PNG format Imagedestroy ($im);//Destroy Image $im } } /* $randcode =new Randcheckcode (); $checkstring = $randcode->get_code (5,7); $image = $randcode->create_check_image ($checkstring); Echo $image; */ ?> Copy Code

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