本文实例讲述了php封装的验证码工具类。分享给大家供大家参考，具体如下：

<?php //验证码工具类 class Captcha{ //属性 private $width; private $height; private $fontsize; private $pixes; private $lines; private $str_len; /* * 构造方法 * @param1 array $arr = array()，初始化属性的关联数组 */ public function __construct($arr = array()){ //初始化 $this->width = isset($arr['width']) ? $arr['width'] : $GLOBALS['config']['captcha']['width']; $this->height = isset($arr['height']) ? $arr['height'] : $GLOBALS['config']['captcha']['height']; $this->fontsize = isset($arr['fontsize']) ? $arr['fontsize'] : $GLOBALS['config']['captcha']['fontsize']; $this->pixes = isset($arr['pixes']) ? $arr['pixes'] : $GLOBALS['config']['captcha']['pixes']; $this->lines = isset($arr['lines']) ? $arr['lines'] : $GLOBALS['config']['captcha']['lines']; $this->str_len = isset($arr['str_len']) ? $arr['str_len'] : $GLOBALS['config']['captcha']['str_len']; } /* * 产生验证码图片 */ public function generate(){ //制作画布 $img = imagecreatetruecolor($this->width,$this->height); //给定背景色 $bg_color = imagecolorallocate($img,mt_rand(200,255),mt_rand(200,255),mt_rand(200,255)); imagefill($img,0,0,$bg_color); //制作干扰线 $this->getLines($img); //增加干扰点 $this->getPixels($img); //增加验证码文字 $captcha = $this->getCaptcha(); //文字颜色 $str_color = imagecolorallocate($img,mt_rand(0,100),mt_rand(0,100),mt_rand(0,100)); //写入文字 //计算文字应该出现的起始位置 $start_x = ceil($this->width/2) - 25; $start_y = ceil($this->height/2) - 8; if(imagestring($img,$this->fontsize,$start_x,$start_y,$captcha,$str_color)){ //成功：输出验证码 header('Content-type:image/png'); imagepng($img); }else{ //失败 return false; } } /* * 获取验证码随机字符串 * @return string $captcha，随机验证码文字 */ private function getCaptcha(){ //获取随机字符串 $str = implode('',array_merge(range('a','z'),range('A','Z'),range(1,9))); //随机取 $captcha = ''; //保存随机字符串 for($i = 0,$len = strlen($str);$i < $this->str_len;$i++){ //每次随机取一个字符 $captcha .= $str[mt_rand(0,$len - 1)] . ' '; } //将数据保存到session $_SESSION['captcha'] = str_replace(' ','',$captcha); //返回值 return $captcha; } /* * 增加干扰点 * @param1 resource $img */ private function getPixels($img){ //增加干扰点 for($i = 0;$i < $this->pixes;$i++){ //分配颜色 $pixel_color = imagecolorallocate($img,mt_rand(100,150),mt_rand(100,150),mt_rand(100,150)); //画点 imagesetpixel($img,mt_rand(0,$this->width),mt_rand(0,$this->height),$pixel_color); } } /* * 增加干扰线 * @param1 resource $img，要增加干扰线的图片资源 */ private function getLines($img){ //增加干扰线 for($i = 0;$i < $this->lines;$i++){ //分配颜色 $line_color = imagecolorallocate($img,mt_rand(150,200),mt_rand(150,200),mt_rand(150,200)); //画线 imageline($img,mt_rand(0,$this->width),mt_rand(0,$this->height),mt_rand(0,$this->width),mt_rand(0,$this->height),$line_color); } } /* * 验证验证码 * @param1 string $captcha，用户提交的验证码 * @return bool，成功返回true，失败返回false */ public static function checkCaptcha($captcha){ //验证码不区分大小写 return (strtolower($captcha) === strtolower($_SESSION['captcha'])); } }

希望本文所述对大家PHP程序设计有所帮助。