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;
    }
}