php 数据流怎么转化为图片

<?php

class imageUpload {
    const ROOT_PATH = './';
    const FAIL_WRITE_DATA = 'Fail to write data';
    //没有数据流
    const NO_STREAM_DATA = 'The post data is empty';
    //图片类型不正确
    const NOT_CORRECT_TYPE = 'Not a correct image type';
    //不能创建文件
    const CAN_NOT_CREATE_FILE = 'Can not create file';
    //上传图片名称
    public $image_name;
    //图片保存名称
    public $save_name;
    //图片保存路径
    public $save_dir;
    //目录+图片完整路径
    public $save_fullpath;     
    public function __construct($save_name, $save_dir) {
        //set_error_handler ( $this->error_handler () );         //设置保存图片名称，若未设置，则随机产生一个唯一文件名
        $this->save_name = $save_name ? $save_name : md5 ( mt_rand (), uniqid () );
        //设置保存图片路径，若未设置，则使用年/月/日格式进行目录存储
        $this->save_dir =  $save_dir ? self::ROOT_PATH .$save_dir : self::ROOT_PATH .date ( 'Y/m/d' );         //创建文件夹
        @$this->create_dir ( $this->save_dir );
        //设置目录+图片完整路径
        $this->save_fullpath = $this->save_dir . '/' . $this->save_name;
    }
    //兼容PHP4
    public function image($save_name) {
        $this->__construct ( $save_name );
    }     public function stream2Image() {
        //二进制数据流
        $data = file_get_contents ( 'php://input' ) ? file_get_contents ( 'php://input' ) : gzuncompress ( $GLOBALS ['HTTP_RAW_POST_DATA'] );
        //数据流不为空，则进行保存操作
        if (! empty ( $data )) {
            //创建并写入数据流，然后保存文件
            if (@$fp = fopen ( $this->save_fullpath, 'w+' )) {
                fwrite ( $fp, $data );
                fclose ( $fp );
                $baseurl = "http://" . $_SERVER ["SERVER_NAME"] . ":" . $_SERVER ["SERVER_PORT"] . dirname ( $_SERVER ["SCRIPT_NAME"] ) . '/' . $this->save_name;
                if ( $this->getimageInfo ( $baseurl )) {
                    echo $baseurl;
                } else {
                    echo ( self::NOT_CORRECT_TYPE  );
                }
            } else {             }
        } else {
            //没有接收到数据流
            echo ( self::NO_STREAM_DATA );
        }
    }
    
    public function create_dir($dirName, $recursive = 1,$mode=0777) {
        ! is_dir ( $dirName ) && mkdir ( $dirName,$mode,$recursive );
    }
    
    public function getimageInfo($imageName = '') {
        $imageInfo = getimagesize ( $imageName );
        if ($imageInfo !== false) {
            $imageType = strtolower ( substr ( image_type_to_extension ( $imageInfo [2] ), 1 ) );
            $imageSize = filesize ( $imageInfo );
            return $info = array ('width' => $imageInfo [0], 'height' => $imageInfo [1], 'type' => $imageType, 'size' => $imageSize, 'mine' => $imageInfo ['mine'] );
        } else {
            //不是合法的图片
            return false;
        }     }      }
?>