<?php check_code(100, 50, 5); function check_code($width = 100, $height = 50, $num = 4, $type = ‘jpeg‘) { $img = imagecreate($width, $height); $string = ‘‘; for ($i = 0; $i < $num; $i++) { $rand = mt_rand(0, 2); switch($rand) { case 0: $ascii = mt_rand(48, 57); break; case 1: $ascii = mt_rand(65, 90); break; case 2: $ascii = mt_rand(97, 122); break; } $string .= sprintf(‘%c‘, $ascii); } imagefilledrectangle($img, 0, 0, $width, $height, randBg($img)); for ($i = 0; $i < 50; $i++) { imagesetpixel($img, mt_rand(0, $width), mt_rand(0, $height), randPix($img)); } for ($i = 0; $i < $num; $i++) { $x = floor($width/$num) *$i + 2; $y = mt_rand(0, $height - 15); imagechar($img, 5, $x, $y, $string[$i], randPix($img)); } $func = ‘image‘ . $type; $header = ‘content-type:image/‘ . $type; if (function_exists($func)) { header($header); $func($img); } else { exit(‘不支持‘); } imagedestroy($img); return $string; } function randBg($img) { return imagecolorallocate($img, mt_rand(130, 255), mt_rand(130, 255), mt_rand(130, 255)); } function randPix($img) { return imagecolorallocate($img, mt_rand(0, 120), mt_rand(0, 120), mt_rand(0, 120)); } ?>