PHP Verification Code Implementation Local refresh

/*
* Auth_code () is a validation code function
* @access Public
* @param int $width Indicates the length of the verification code and defaults to 80
* @param int $height Indicates the height of the verification code, and defaults to 20
* @param int $num represents the number of digits in the verification code, which defaults to 4
* @param int $line represents the number of lines in the centerline of the validation code, which defaults to 4
* @param int $line represents the number of points in the verification code, default is 150
*/

The code is as follows

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function Auth_code ($width =, $height = $num = 4, $line = 4, $dot = 150) { $length = Floor ($width/$num); Floor: Take integer part length: Average length per paragraph for ($i =0; $i < $num; $i + +) @ $rand. =dechex (Mt_rand (1,15)); $_session[' code ']= $rand; Create a new artboard with a black bottom $im =imagecreatetruecolor ($width, $height); Take color $green =imagecolorallocate ($im, 0,255,0); $red = Imagecolorallocate ($im, 255,0,0); $white =imagecolorallocate ($im, 255,255,255); $black = Imagecolorallocate ($im, 0,0,0); Fill artboard Imagefill ($im, 0,0, $green); Draw Line for ($i =0; $i < $line; $i + +) { $color =imagecolorallocate ($im, Rand (0,255), Rand (0,255), Rand (0,255)); Imageline ($im, rand ($width -10), 0,rand (0, $width), $height, $color); } Draw a Point for ($i =0; $i < $dot; $i + +) { $color =imagecolorallocate ($im, Rand (0,255), Rand (0,255), Rand (0,255)); Imagesetpixel ($im, rand (0, $width), rand (0, $height), $color); } Draw a number for ($i =0; $i < $num; $i + +) { Imagestring ($im, 5,mt_rand ($i * $length +1, ($i + 1) * $length -8), Mt_rand (0, $height -14), $_session[' code ' [$i], $white); } Output picture Header ("Content-type:image/jpeg"); Imagejpeg ($im); }

 -main functions:
       imagecreatetruecolor //new artboard with black bottom
        imagecolorallocate    //Fetch color
       imagefill                     //Fill artboard
       imageline                  //Draw line
        imagesetpixel          /DOT
        imagestring            /Draw String ( This code is numeric)
       Note: When you draw the digital verification code on the artboard, you should pay attention to the font out of bounds, so you should subtract some range, as detailed in the attachment.
   -Local Refresh verification code:

code is as follows	copy code