PHP图片操作类

１，生成缩图

<?php
///生成縮圖
///$resizeimage=new resizeimage($filesaved,$dstimg,250,250);
class resizeimage 
{ 
    var $type; 
    var $width; 
    var $height; 
    var $resize_width; 
    var $resize_height; 
    var $srcimg; 
    var $dstimg; 
    var $im;
    var $desiredRatio;

    function resizeimage($srcimg,$dstimg, $wid, $hei) 
    { 
        $this->srcimg = $srcimg; 
        $this->dstimg = $dstimg; 
        //圖片的類型 
        $this->type = substr(strrchr($this->srcimg,"."),1); 
        //初始化圖像 
        if($this->type=="jpg") 
            $this->im = imagecreatefromjpeg($this->srcimg); 
        if($this->type=="gif") 
            $this->im = imagecreatefromgif($this->srcimg); 
        if($this->type=="png") 
            $this->im = imagecreatefrompng($this->srcimg);
            
        //目標圖像寬和高
        $this->width = imagesx($this->im); 
        $this->height = imagesy($this->im);
        //計算縮圖的寬和高
        //若需要生產的縮圖的寬和高都大於源圖的寬高時都不需要縮小
        if( ($this->width<=$wid) && ($this->height<=$hei) ){
            $this->resize_width=$this->width;
            $this->resize_height=$this->height;
        }else{
            //若寬的縮小比例小於高的縮小比例時,則成生的縮圖的寬為$wid
            if( ($wid/$this->width) < ($hei/$this->height) ){
                $this->desiredRatio=$wid/$this->width;
                $this->resize_width=$wid;
                $this->resize_height=(int)($this->height*$this->desiredRatio);
            //若寬的縮小比例大於高的縮小比例時,則生成的縮圖的高為$hei
            }else{
                $this->desiredRatio=$hei/$this->height;
                $this->resize_height=$hei;
                $this->resize_width=(int)($this->width*$this->desiredRatio);
            }
        }
        //生成圖像
        $this->newimg(); 
        //销毁一图像
        ImageDestroy ($this->im); 
    } 
    function newimg() 
    { 
        $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height); 
        imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, $this->width, $this->height) ; 
        ImageJpeg ($newimg,$this->dstimg); 
    }    
} 
?>