求 php 图片压缩代码

Question

学习中，php可以生成缩略图吗，

Answer 1

可以生成function createThumbImage($original,$thumb_path,$new_width=50,$new_height=50,$ext=null)
{
if ($ext==null)
{
$ext=end(explode(".",$original));
}
$ext=strtolower($ext);
$filename = $original;
list($width, $height) = getimagesize($filename);
$image_p = imagecreatetruecolor($new_width, $new_height); switch ($ext)
{
case 'jpg':
$image = imagecreatefromjpeg($filename);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
imagejpeg($image_p, $thumb_path, 100);
return true;
case 'gif':
$image = imagecreatefromgif($filename);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
imagegif($image_p, $thumb_path, 100);
return true;
case 'png':
$image = imagecreatefrompng($filename);
imagecopyresampled($image_p, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height);
imagepng($image_p, $thumb_path, 100);
return true;
}
return false;
}
这段代码我参考ice_berg的代码的，忘记了是否经过修改。。

Answer 2

摘自:木目子技术交流站
/**
    * 生成一个缩略图
    * @params $Image:String;
    * @return String;
    */
    function make2small($Image)
    {
        $info=$this->getInfo($Image);
        if(!$info)
        {
            return 0;
        }        $file=$this->DOC_ROOT.$this->Path."/".$Image;        /*随即生成一个文件名*/
        $small=$this->make_rand(16).$this->mimePhoto[$info["mime"]];        if(@file_exists($this->DOC_ROOT.$this->Path."/".$small))
        {
            return $this->make2small($Image);
        }        /*如果大图小于小缩略图，则直接拷贝一份*/
        if($this->width>=$info["width"] && $this->heigh>=$info["heigh"])
        {
            if(@copy($file,$this->DOC_ROOT.$this->smallPath."/".$small))
            {
                return $small;
            }else{
                return 0;
            }
        }
        /*按照比例得到缩略图的高、宽*/
        if(($info["width"] / $info["heigh"]) > ($this->width / $this->heigh))
        {
            $w=$this->width;
            $h=floor($info["heigh"]*$w / $info["width"]);
        }else{
            $h=$this->heigh;
            $w=floor($info["width"]*$h / $info["heigh"]);
        }
        /*创建缩略图*/
        switch($info["mime"])
        {
            case "image/gif":
                $im=@imagecreatefromgif($file);
                break;
            case "image/pjpeg":
            case "image/jpeg":
                $im=@imagecreatefromjpeg($file);
                break;
            case "image/png":
                $im=@imagecreatefrompng($file);
                break;
            default:
                return -1;
        }
        if($im)
        {
            $ni=@imagecreatetruecolor($w,$h);
            @imagecopyresampled($ni,$im,0,0,0,0,$w,$h,$info["width"],$info["heigh"]);
            $result=@imagejpeg($ni,$this->DOC_ROOT.$this->smallPath."/".$small);
            @imagedestroy($ni);
        }            @imagedestroy($im);
        if($result)
        {
            return $small;
        }
        return "NoSmall.gif";
    }