<?php    /**    *  vcode    *  param   $w画布宽    *  param   $h 画布高    *  param   $fnum 验证码元素个数    *  param   $fontsize 验证码元素大小    *  param   $obs  干扰素个数    */    function vcode($w, $h, $fnum, $fontsize, $obs) {    $img = imagecreatetruecolor($w,  $h);        $white = imagecolorallocate($img, 255, 255, 255);    $black = imagecolorallocate($img, 0 , 0, 0);    $gray = imagecolorallocate($img, 180, 180, 180);    imagefill($img, 0, 0, $gray);            for ($i=0; $i < $obs; $i++) {         imagesetpixel($img, rand(0, $w), rand(0, $h), $black);    }    $x = ($w - $fnum * $fontsize) / 2;    $y = $h / 2 + $fontsize / 2;    $fontfile = "final/fonts/msyh.ttf";    $arr = array_merge(range(0,9), range('a', 'z'), range('A', 'Z'));    shuffle($arr);    $str=implode(array_slice($arr, 0, $fnum));    imagettftext($img, $fontsize, 0, $x, $y, $black, $fontfile, $str);    header("content-type:image/jpeg");    imagejpeg($img);    imagedestroy($img);}    vcode(80, 40, 4, 15, 1000);