PHP缩略图类

 class ThumbImages{
     /**
      * 生成缩略图
      * prorate 按比例缩放
      * distortion 扭曲型缩图
      * cut 最小裁剪后的缩图
      * backFill 背景填充图
      * clssname ThumbImages
      * createtime:2014-1-14下午04:44:28
      * author:lhm
      * for example
      * include 'ThumbImages.class.php'
      * $th=new ThumbImages(array('imagePre'=>'',
      *                           'imagePath'=>'./uploads/thumb/',
      *                           'echoType'=>'file'));
      * $th->setThumb($srcImage, 384, 300, 'prorate');
      */
     private $imagepre;               //缩略图名称前缀
     private $imagepath;             //缩略图存放路径
     private $srcImage='';          //源图路径
     private $newImageName;        //缩略图名称
     private $imageType;           //图片类型
     private $echotype;          //输出图片类型，link--直接输出到浏览器；file--保存为文件
     private $im='';            //临时变量
     private $originName='';   //源图名称
     private $srcW='';        //源图宽
     private $srcH='';       //源图高
     private $errorNum=0;   //错误号
     private $errorMess='';//用来提供错误报告

     public function __construct($options = array()){
         $allowOption = array('imagepre','imagepath','echotype');
         foreach($options as $key=>$val){
             $key = strtolower($key);
             //查看用户参数中数组的下标是否和成员属性名相同
             //if(!in_array($key,get_class_vars(get_class($this)))){
             if(!in_array($key, $allowOption)){
                 $this->errorNum = -3;
                 $this->errorMess = $this->getError();
                 continue 1;
             }
             $this->$key = $val;
         }
     }
     /**
      *
      * 判断源文件路径、缩略图存放路径是否正确
      * 判断GD库是否支持缩略图格式
      * 初始化图片高宽、缩略图存放路径、缩略图生成方式
      * @param string $srcImage
      * @param int $toW
      * @param int $toH
      * @param string $method
      * @param string $echotype
      */
     public function setThumb($srcImage = '', $toW = 0, $toH = 0, $method = 'distortion'){
         $this->srcImage = $srcImage;
         $imageName = explode('/', $this->srcImage);
         $this->originName = $imageName[2];
            //检查源文件是否存在
         if(empty($srcImage) || filetype($srcImage) != 'file'){
             $this->errorNum = 4;
             $this->errorMess = $this->getError();
             return false;
         }
         //检查文件上传路径
         if ($this->echotype == 'file'){
             if(!$this->checkImagePath()){
                 $this->errorMess = $this->getError();
                 return false;
             }
         }
         $info = '';
         $data = getimagesize($this->srcImage, $info);//获取图像大小
         $this->srcW = $data[0];//宽
         $this->srcH = $data[1];//高
          //检查GD库
         if(!$this->checkGD($data[2])){
             $this->errorMess = $this->getError();
             return false;
         }
         $this->setImageName();//设置缩略图名称
         $toFile = $this->imagepath.$this->newImageName;//缩略图存放路径
         $return = $this->createImageMethod($method, $toFile, $toW, $toH);
           return $return;
     }
     /**
      *
      * 初始化缩略图生成方式
      * prorate 按比例缩放
      * distortion 扭曲型缩图
      * cut 最小裁剪后的缩图
      * backFill 背景填充图
      * @param string $method
      * @param string $toFile
      * @param int $toW
      * @param int $toH
      */
     private function createImageMethod($method, $toFile, $toW, $toH){
         switch ($method){
               case 'prorate':
                   $return = $this->prorate($toFile, $toW, $toH);
                   break;
               case 'cut':
                   $return = $this->cut($toFile, $toW, $toH);
                   break;
               case 'backFill':
                   $return = $this->backFill($toFile, $toW, $toH);
                   break;
               default:
                   $return = $this->distortion($toFile, $toW, $toH);
            }
            return $return;
     }
     //生成扭曲型缩图
     function distortion($toFile='', $toW=0, $toH=0){
         $cImg=$this->creatImage($this->im, $toW, $toH, 0, 0, 0, 0, $this->srcW, $this->srcH);
         return $this->echoImage($cImg, $toFile);
         imagedestroy($cImg);
     }

     //生成按比例缩放的缩图
     function prorate($toFile, $toW, $toH){
         $toWH = $toW / $toH;
         $srcWH = $this->srcW / $this->srcH;
         if($toWH <= $srcWH){
             $ftoW = $toW;
             $ftoH = $ftoW * ($this->srcH / $this->srcW);
         }else{
               $ftoH = $toH;
               $ftoW = $ftoH * ($this->srcW / $this->srcH);
         }
         if($this->srcW > $toW || $this->srcH > $toH){
             $cImg = $this->creatImage($this->im, $ftoW, $ftoH, 0, 0, 0, 0, $this->srcW, $this->srcH);
             return $this->echoImage($cImg, $toFile);
             imagedestroy($cImg);
         }else{
             $cImg = $this->creatImage($this->im, $this->srcW, $this->srcH, 0, 0, 0, 0, $this->srcW, $this->srcH);
             return $this->echoImage($cImg, $toFile);
             imagedestroy($cImg);
         }
     }

     //生成最小裁剪后的缩图
     private function cut($toFile, $toW, $toH){
           $toWH = $toW/$toH;
           $srcWH = $this->srcW / $this->srcH;
           if($toWH <= $srcWH){
                $ctoH = $toH;
                $ctoW = $ctoH * ($this->srcW / $this->srcH);
           }else{
               $ctoW = $toW;
               $ctoH = $ctoW * ($this->srcH / $this->srcW);
           }
         $allImg = $this->creatImage($this->im, $ctoW, $ctoH, 0, 0, 0, 0, $this->srcW, $this->srcH);
         $cImg = $this->creatImage($allImg, $toW, $toH, 0, 0, ($ctoW-$toW) / 2, ($ctoH-$toH) / 2, $toW, $toH);
         return $this->echoImage($cImg, $toFile);
         imagedestroy($cImg);
         imagedestroy($allImg);
     }

     //生成背景填充的缩图
     private function backFill($toFile, $toW, $toH, $bk1=255, $bk2=255, $bk3=255){
         $toWH = $toW / $toH;
         $srcWH = $this->srcW / $this->srcH;
         if($toWH <= $srcWH){
             $ftoW = $toW;
             $ftoH = $ftoW * ($this->srcH / $this->srcW);
         }else{
               $ftoH = $toH;
               $ftoW = $ftoH*($this->srcW / $this->srcH);
         }
         if(function_exists("imagecreatetruecolor")){
             @$cImg = imagecreatetruecolor($toW,$toH);
             if(!$cImg){
                 $cImg = imagecreate($toW,$toH);
             }
         }else{
             $cImg = imagecreate($toW,$toH);
         }
         $backcolor = imagecolorallocate($cImg, $bk1, $bk2, $bk3);        //填充的背景颜色
         imagefilledrectangle($cImg,0,0,$toW,$toH,$backcolor);
         if($this->srcW > $toW || $this->srcH > $toH){
             $proImg = $this->creatImage($this->im,$ftoW,$ftoH,0,0,0,0,$this->srcW,$this->srcH);
             if($ftoW < $toW){
                  imagecopy($cImg, $proImg, ($toW - $ftoW) / 2, 0, 0, 0, $ftoW, $ftoH);
             }else if($ftoH < $toH){
                  imagecopy($cImg, $proImg, 0, ($toH-$ftoH) / 2, 0, 0, $ftoW, $ftoH);
             }else{
                  imagecopy($cImg, $proImg, 0, 0, 0, 0, $ftoW, $ftoH);
             }
         }else{
              imagecopymerge($cImg, $this->im, ($toW - $ftoW) / 2,($toH - $ftoH) / 2, 0, 0, $ftoW, $ftoH, 100);
         }
         return $this->echoImage($cImg, $toFile);
         imagedestroy($cImg);
     }
     //创建图像
     private function creatImage($img, $creatW, $creatH, $dstX, $dstY, $srcX, $srcY, $srcImgW, $srcImgH){
         if(function_exists("imagecreatetruecolor")){
             @$creatImg = imagecreatetruecolor($creatW, $creatH);
             if($creatImg){
                 imagecopyresampled($creatImg, $img, $dstX, $dstY, $srcX, $srcY, $creatW, $creatH, $srcImgW, $srcImgH);
             }else{
                 $creatImg=imagecreate($creatW,$creatH);
                 imagecopyresized($creatImg, $img, $dstX, $dstY, $srcX, $srcY, $creatW, $creatH, $srcImgW, $srcImgH);
             }
          }else{
             $creatImg=imagecreate($creatW, $creatH);
             imagecopyresized($creatImg, $img, $dstX, $dstY, $srcX, $srcY, $creatW, $creatH, $srcImgW, $srcImgH);
          }
          return $creatImg;
     }

     //输出图片，link---只输出，不保存文件。file--保存为文件
     function echoImage($img, $toFile){
         switch($this->echotype){
             case 'link':
                 if(function_exists('imagejpeg'))
                     return imagejpeg($img);
                 else
                     return imagepng($img);
                 break;
             case 'file':
                 if(function_exists('imagejpeg'))
                     return imagejpeg($img,$toFile);
                 else
                     return imagepng($img,$toFile);
                 break;
         }
     }
     /**
      *
      * 设置随机文件名称
      * @access private
      * @return string
      */
     private function setRandName(){
         $fileName = date("YmdHis").rand(100,999);
         return $fileName.'.'.$this->imageType;
     }
     private function setImageName(){
         if ($this->imagepre != ''){
             $this->newImageName = $this->imagepre.'_'.$this->setRandName();
         }else {
             $this->newImageName = $this->setRandName();
         }
     }
     /**
      *
      * 用来检查文件上传路径
      * @access private
      * @return bool
      */
     private function checkImagePath(){
         if(empty($this->imagepath)) {
             $this->errorNum = -2;
             return false;
         }

         if(!file_exists($this->imagepath) || !is_writable($this->imagepath)){
             if(!@mkdir($this->imagepath, 0755)){
                 $this->errorNum = -1;
                 return false;
             }
         }
         return true;
     }
     private function checkGD($imageType){
         switch ($imageType){
              case 1:
                if(!function_exists("imagecreatefromgif")){
                        $this->errorNum = 1;
                        return false;
                }
                $this->imageType = 'gif';
                $this->im = imagecreatefromgif($this->srcImage);
                break;
              case 2:
                if(!function_exists("imagecreatefromjpeg")){
                      $this->errorNum = 2;
                      return false;
                 }
                 $this->imageType = 'jpg';
                 $this->im = imagecreatefromjpeg($this->srcImage);
                 break;
              case 3:
                 if(!function_exists("imagecreatefrompng")){
                       $this->errorNum = 3;
                       return false;
                  }
                  $this->imageType = 'png';
                  $this->im = imagecreatefrompng($this->srcImage);
                  break;
               default:
                  $this->errorNum = 0;
                  return false;
           }
           return true;
     }
     /**
      *
      * 用于获取上传后缩略图片的文件名
      * @access public
      * @return string
      */
     public function getNewImageName(){
         return $this->newImageName;
     }

     /**
      *
      * 获取上传错误信息
      * @access private
      * @return string
      */
     private function getError(){
         $str='生成缩略图<font color="red">'.$this->originName.'</font>时出错：';

         switch($this->errorNum){
             case 4: $str .= '没有找到需要缩略的图片';
                 break;
             case 3: $str .= '你的GD库不能使用png格式的图片，请使用其它格式的图片！';
                 break;
             case 2: $str .= '你的GD库不能使用jpeg格式的图片，请使用其它格式的图片！';
                 break;
             case 1: $str .= '你的GD库不能使用GIF格式的图片，请使用Jpeg或PNG格式！';
                 break;
             case -1: $str .= '建立存放缩略图目录失败，请重新指定缩略图目录';
                 break;
             case -2: $str .= '必须指定缩略图的路径';
                 break;
             case -3: $str .= '初始化参数出错';
                 break;
             default: $str .= '末知错误';
         }

         return $str.'<br>';
     }
     public function getErrorMsg() {
         return $this->errorMess;
     }
 }