如何用PHP编写的图片验证码类文件

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适用于自定义的验证码类！

code_len;$i++ ){      $code .= $this->code_str[mt_rand(0, strlen($this->code_str)-1)];  }    return $this->code = $code;  }     //输出图像  public function getImage(){    $w = $this->width;    $h = $this->height;    $bg_color = $this->bg_color;    $img = imagecreatetruecolor($w, $h);    $bg_color = imagecolorallocate($img,   hexdec(substr($bg_color, 1,2)), hexdec(substr($bg_color, 3,2)), hexdec(substr($bg_color, 5,2)));  imagefill($img, 0, 0, $bg_color);    $this->img = $img;    $this->create_font();    $this->create_pix();  $this->show_code();  }    //写入验证码  public function create_font(){    $this->create_code();    $color = $this->font_color;    $font_color = imagecolorallocate($this->img, hexdec(substr($color,1,2)), hexdec(substr($color, 3,2)), hexdec(substr($color,5,2)));    $x = $this->width/$this->code_len;    for( $i=0;$i<$this->code_len;$i++ ){      $txt_color = imagecolorallocate($this->img, mt_rand(0,100), mt_rand(0, 150), mt_rand(0, 200));      imagettftext($this->img, $this->font_size, mt_rand(-30, 30), $x*$i+mt_rand(3, 6), mt_rand($this->height/1.2, $this->height), $txt_color, $this->font , $this->code[$i]);       //imagestring($this->img, $this->font_size, $x*$i+mt_rand(3, 6),mt_rand(0, $this->height/4) , $this->code[$i], $font_color);    }    $this->font_color = $font_color;  }     //画干扰线  public function create_pix(){    $pix_color= $this->font_color;    for($i=0;$i<100;$i++){      imagesetpixel($this->img, mt_rand(0, $this->width),mt_rand(0, $this->height), $pix_color);    }    for($j=0;$j<4;$j++){      imagesetthickness($this->img, mt_rand(1, 2));      imageline($this->img, mt_rand(0, $this->width), mt_rand(0, $this->height), mt_rand(0, $this->width), mt_rand(0, $this->height), $pix_color);    }  }     //得到验证码  public function getCode(){    return strtoupper($this->code);  }    //输出验证码  private function show_code(){    header("Content-type:image/png");    imagepng($this->img);    imagedestroy($this->img);  }}

我们再来看一例代码：

生成图片类型验证码，验证码包含数字和大写字母，session中存放md5加密后的验证码

buildAndExportImage(); *  * 作     者: luojing * 创建时间: 2013-3-27 上午11:42:12 */class Captcha {                private $width;//宽度        private $height; //高度        private $codeNum;//验证码字符数量        private $image;//验证码图像资源        private $sessionKey;//session中保存的名字        private $captcha;//验证码字符串        const charWidth = 10;//单个字符宽度,根据输出字符大小而变                /**         * 创建验证码类，初始化相关参数         * @param $width 图片宽度         * @param $height 图片高度         * @param $codeNum 验证码字符数量         * @param $sessionKey session中保存的名字         */        function __construct($width = 50, $height = 20, $codeNum = 4, $sessionKey = 'captcha') {                $this->width = $width;                $this->height = $height;                $this->codeNum = $codeNum;                $this->sessionKey = $sessionKey;                                //保证最小高度和宽度                if($height < 20) {                        $this->height = 20;                }                if($width < ($codeNum * self::charWidth + 10)) {//左右各保留5像素空隙                        $this->width = $codeNum * self::charWidth + 10;                }        }                /**         * 构造并输出验证码图片         */        public function buildAndExportImage() {                $this->createImage();                $this->setDisturb();                $this->setCaptcha();                $this->exportImage();        }                /**         * 构造图像，设置底色         */        private function createImage() {                //创建图像                $this->image = imagecreatetruecolor($this->width, $this->height);                 //创建背景色                $bg = imagecolorallocate($this->image, mt_rand(220, 255), mt_rand(220, 255), mt_rand(220, 255));                 //填充背景色                imagefilledrectangle($this->image, 0, 0, $this->width - 1, $this->height - 1, $bg);        }                /**         * 设置干扰元素         */        private function setDisturb() {                                //设置干扰点                for($i = 0; $i < 150; $i++) {                        $color = imagecolorallocate($this->image, mt_rand(150, 200), mt_rand(150, 200), mt_rand(150, 200));                        imagesetpixel($this->image, mt_rand(5, $this->width - 10), mt_rand(5, $this->height - 3), $color);                }                                //设置干扰线                for($i = 0; $i < 10; $i++) {                        $color = imagecolorallocate($this->image, mt_rand(150, 220), mt_rand(150, 220), mt_rand(150, 220));                        imagearc($this->image, mt_rand(-10, $this->width), mt_rand(-10, $this->height), mt_rand(30, 300), mt_rand(20, 200), 55, 44, $color);                }                                //创建边框色                $border = imagecolorallocate($this->image, mt_rand(0, 50), mt_rand(0, 50), mt_rand(0, 50));                //画边框                imagerectangle($this->image, 0, 0, $this->width - 1, $this->height - 1, $border);        }                /**         * 产生并绘制验证码         */        private function setCaptcha() {                $str = '23456789ABCDEFGHJKLMNPQRSTUVWXYZ';                //生成验证码字符                for($i = 0; $i < $this->codeNum; $i++) {                        $this->captcha .= $str{mt_rand(0, strlen($str) - 1)};                }                //绘制验证码                for($i = 0; $i < strlen($this->captcha); $i++) {                        $color = imagecolorallocate($this->image, mt_rand(0, 200), mt_rand(0, 200), mt_rand(0, 200));                        $x = floor(($this->width - 10)/$this->codeNum);                        $x = $x*$i + floor(($x-self::charWidth)/2) + 5;                        $y = mt_rand(2, $this->height - 20);                        imagechar($this->image, 5, $x, $y, $this->captcha{$i}, $color);                }        }                /*         * 输出图像,验证码保存到session中         */        private function exportImage() {                if(imagetypes() & IMG_GIF){                        header('Content-type:image/gif');                        imagegif($this->image);                } else if(imagetypes() & IMG_PNG){                        header('Content-type:image/png');        imagepng($this->iamge);                } else if(imagetypes() & IMG_JPEG) {                        header('Content-type:image/jpeg');        imagepng($this->iamge);                } else {                        imagedestroy($this->image);                        die("Don't support image type!");                }                //将验证码信息保存到session中，md5加密                if(!isset($_SESSION)){              session_start();                }                 $_SESSION[$this->sessionKey] = md5($this->captcha);                    imagedestroy($this->image);         }                function __destruct() {                unset($this->width, $this->height, $this->codeNum,$this->captcha);        }}

例三：

width=$width;  $this->height=$height;  $this->codeNum=$codeNum;  $this->checkCode=$this->createCheckCode();  $number=floor($width*$height/15);   if($number > 240-$codeNum){  $this->disturbColorNum= 240-$codeNum;  }else{  $this->disturbColorNum=$number;  }  } //通过访问该方法向浏览器中输出图像 function showImage($fontFace=""){  //第一步：创建图像背景  $this->createImage();  //第二步：设置干扰元素  $this->setDisturbColor();  //第三步：向图像中随机画出文本  $this->outputText($fontFace);  //第四步：输出图像  $this->outputImage(); }  //通过调用该方法获取随机创建的验证码字符串 function getCheckCode(){  return $this->checkCode; } private function createImage(){  //创建图像资源  $this->image=imagecreatetruecolor($this->width, $this->height);  //随机背景色  $backColor=imagecolorallocate($this->image, rand(225, 255), rand(225,255), rand(225, 255));  //为背景添充颜色  imagefill($this->image, 0, 0, $backColor);  //设置边框颜色  $border=imagecolorallocate($this->image, 0, 0, 0);  //画出矩形边框  imagerectangle($this->image, 0, 0, $this->width-1, $this->height-1, $border); } private function setDisturbColor(){  for($i=0; $i<$this->disturbColorNum; $i++){  $color=imagecolorallocate($this->image, rand(0, 255), rand(0, 255), rand(0, 255));  imagesetpixel($this->image, rand(1, $this->width-2), rand(1, $this->height-2), $color);  }  for($i=0; $i<10; $i++){  $color=imagecolorallocate($this->image, rand(200, 255), rand(200, 255), rand(200, 255));  imagearc($this->image, rand(-10, $this->width), rand(-10, $this->height), rand(30, 300), rand(20, 200), 55, 44, $color);  } } private function createCheckCode(){//这里主要产生随机码，从2开始是为了区分1和l  $code="23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKMNPQRSTUVWXYZ";  $string='';  for($i=0; $i < $this->codeNum; $i++){  $char=$code{rand(0, strlen($code)-1)};  $string.=$char;  }  return $string; } private function outputText($fontFace=""){  for($i=0; $i<$this->codeNum; $i++){  $fontcolor=imagecolorallocate($this->image, rand(0, 128), rand(0, 128), rand(0, 128));  if($fontFace==""){   $fontsize=rand(3, 5);   $x=floor($this->width/$this->codeNum)*$i+3;   $y=rand(0, $this->height-15);   imagechar($this->image,$fontsize, $x, $y, $this->checkCode{$i},$fontcolor);  }else{   $fontsize=rand(12, 16);   $x=floor(($this->width-8)/$this->codeNum)*$i+8;   $y=rand($fontSize+5, $this->height);   imagettftext($this->image,$fontsize,rand(-30, 30),$x,$y ,$fontcolor, $fontFace, $this->checkCode{$i});  }  } } private function outputImage() {  if(imagetypes() & IMG_GIF){  header("Content-Type:image/gif");  imagepng($this->image);  }else if(imagetypes() & IMG_JPG){  header("Content-Type:image/jpeg");  imagepng($this->image);  }else if(imagetypes() & IMG_PNG){  header("Content-Type:image/png");  imagepng($this->image);  }else if(imagetypes() & IMG_WBMP){  header("Content-Type:image/vnd.wap.wbmp");  imagepng($this->image);  }else{  die("PHP不支持图像创建");  } } function __destruct(){  imagedestroy($this->image); } }

使用如下：

测试，调用验证码类
code.php

showImage();  //输出到页面中供 注册或登录使用$_SESSION["code"]=$code->getCheckCode(); //将验证码保存到服务器中

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