php下不错的缩略图类

<?php
    /**
     * 生成缩略图(支持加载图片文件和字符串2种方式)
     * @param       $maxWidth       缩略图最大宽度
     * @param       $maxHeight      缩略图最大高度
     * @param       bool    $scale  是否按比例缩小，否则拉伸
     * @param       bool    $inflate        是否放大以来填充缩略图         
     */
    class Thumbnail {
    
            private $maxWidth;
            private $maxHeight;
            private $scale;
            private $inflate;
            private $types;
            private $imgLoaders;
            private $imgCreators;
            private $source;
            private $sourceWidth;
            private $sourceHeight;
            private $sourceMime;
            private $thumb;
            private $thumbWidth;
            private $thumbHeight;
    
            public function __construct($maxWidth, $maxHeight, $scale = true, $inflate = true) {
                    $this->maxWidth = $maxWidth;
                    $this->maxHeight = $maxHeight;
                    $this->scale = $scale;
                    $this->inflate = $inflate;
                    $this->types = array(
                        'image/jpeg',
                        'image/png',
                        'image/gif'
                    );
                    //加载MIME类型图像的函数名称
                    $this->imgLoaders = array(
                        'image/jpeg'        =>      'imagecreatefromjpeg',
                        'image/png'         =>      'imagecreatefrompng',
                        'image/gif'         =>      'imagecreatefromgif'
                    );
                    //储存创建MIME类型图片的函数名称
                    $this->imgCreators = array(
                        'image/jpeg'        =>      'imagejpeg',
                        'image/png'         =>      'imagepng',
                        'image/gif'         =>      'imagegif'
                    );          
            }
            /**
             * 文件方式加载图片
             * @param       string  $image 源图片
             * @return      bool   
             */
            public function loadFile($image){
                    if(!$dims = @getimagesize($image)){
                            trigger_error("源图片不存在");
                    }
                    if(in_array($dims['mime'], $this->types)){
                            $loader = $this->imgLoaders[$dims['mime']];
                            $this->source = $loader($image);
                            $this->sourceWidth = $dims[0];
                            $this->sourceHeight = $dims[1];
                            $this->sourceMime = $dims['mime'];
                            $this->initThumb();
                            return TRUE;
                    }else{
                            trigger_error('不支持'.$dims['mime']."图片类型");
                    }
        }
            /**
             * 字符串方式加载图片
             * @param       string $image  字符串
             * @param       string $mime    图片类型
             * @return type
             */
            public function loadData($image,$mime){
                    if(in_array($mime, $this->types)){
                            if($this->source = @imagecreatefromstring($image)){
                                    $this->sourceWidth = imagesx($this->source);
                                    $this->sourceHeight = imagesy($this->source);
                                    $this->sourceMime = $mime;
                                    $this->initThumb();
                                    return TRUE;
                            }else{
                                    trigger_error("不能从字符串加载图片");
                            }
                    }else{
                            trigger_error("不支持".$mime."图片格式");
                    }
            }
            /**
             * 生成缩略图
             * @param       string  $file   文件名。如果不为空则储存为文件，否则直接输出到浏览器
             */
            public function buildThumb($file = null){
                    $creator = $this->imgCreators[$this->sourceMime];
                    if(isset($file)){
                            return $creator($this->thumb,$file);
                    }else{
                            return $creator($this->thumb);
                    }
            }
            /**
             * 处理缩放
             */
            public function initThumb(){
                    if($this->scale){
                            if($this->sourceWidth > $this->sourceHeight){
                                    $this->thumbWidth = $this->maxWidth;
                                    $this->thumbHeight = floor($this->sourceHeight*($this->maxWidth/$this->sourceWidth));
                            }elseif($this->sourceWidth < $this->sourceHeight){
                                $this->thumbHeight = $this->maxHeight;
                                    $this->thumbWidth = floor($this->sourceWidth*($this->maxHeight/$this->sourceHeight));
                            }else{
                                    $this->thumbWidth = $this->maxWidth;
                                    $this->thumbHeight = $this->maxHeight;
                            }
                    }
                    $this->thumb = imagecreatetruecolor($this->thumbWidth, $this->thumbHeight);
                     
                    if($this->sourceWidth <= $this->maxWidth && $this->sourceHeight <= $this->maxHeight && $this->inflate == FALSE){
                            $this->thumb = $this->source;
                    }else{
                            imagecopyresampled($this->thumb, $this->source, 0, 0, 0, 0, $this->thumbWidth, $this->thumbHeight, $this->sourceWidth, $this->sourceHeight);
                    }
            }
             
            public function getMine(){
                    return $this->sourceMime;
            }
             
            public function getThumbWidth(){
                    return $this->thumbWidth;
            }
             
            public function getThumbHeight(){
                    return $this->thumbHeight;
            }
    
    }