<?php class resize_image{    private $o_img_width;//原图像宽度    private $o_img_height;//原图像高度    private $n_img_width;//新图像宽度    private $n_img_height;//新图像高度    private $o_img_file;//原图像文件    private $o_img_source;//原图像资源    private $n_img_file;//新图像资源    private $n_img_source;//新图像资源    private $o_to_n_per=0.5;//图像缩放比    //初始化内部变量    function __construct($oldfile,$newfile){        list($width,$height)=getimagesize($oldfile);        $this->o_img_file=$oldfile;        $this->o_img_width=$width;        $this->o_img_height=$height;        $this->n_img_file=$newfile;    }    //等比例缩放并且解决GIF透明色为黑色背景的问题    function get_resize_scaling_img(){        $this->n_img_width=$this->o_img_width*$this->o_to_n_per;        $this->n_img_height=$this->o_img_height*$this->o_to_n_per;        //等比例缩放图片(算法)        if ( $this->n_img_width && ( $this->o_img_width <$this->o_img_height))        {              $this->n_img_width = ( $this->n_img_height/$this->o_img_height) * $this->o_img_width;        }        else        {             $this->n_img_height = ($this->n_img_width / $this->o_img_width) * $this->o_img_height;        }        $this->o_img_source=imagecreatefromgif($this->o_img_file);        //创建一个等比例缩放大小的画布        $this->n_img_source=imagecreatetruecolor($this->o_img_width,$this->n_img_height);        //美化:去除黑色不透明背景        $trans_init=imagecolortransparent($this->o_img_source);        //寻找透明色并且判断是否在总颜色中        if($trans_init>=0 && $trans_init < imagecolorstotal($this->o_img_source)){            //如果在的话则搜索这个颜色的RGB色相            $trans_index=imagecolorsforindex($this->o_img_source,$trans_init);            //找到之后就创建这样一个颜色            $trans_new=imagecolorallocate($this->n_img_source,$trans_index["red"],$trans_index["green"],$trans_index["blue"]);            //然后我们用这个颜色去填充新的图像            imagefill($this->n_img_source,0,0,$trans_new);            //然后我们在把填充色设置为透明            imagecolortransparent($this->n_img_source,$trans_new);        }        //拷贝原图像到新画板上        imagecopyresized($this->n_img_source,$this->o_img_source,0,0,0,0,$this->n_img_width,$this->n_img_height,$this->o_img_width,$this->o_img_height);        return $this->n_img_source;    }    //最终销毁资源    function __destruct(){        imagedestroy($this->o_img_source);        imagedestroy($this->n_img_source);    } }