PHP生成缩略图

/** * 生成唯一字符串 * @return string */function getUniName(){return md5(uniqid(microtime(true),true));}/** * 得到文件的扩展名 * @param string $filename * @return string */function getExt($filename){return strtolower(end(explode(".",$filename)));}

/** * 生成缩略图 * @param string $filename * @param string $destination * @param int $dst_w * @param int $dst_h * @param bool $isReservedSource * @param number $scale * @return string */function thumb($filename,$destination=null,$dst_w=null,$dst_h=null,$isReservedSource=true,$scale=0.5){//默认不保留源文件$isReservedSource=falselist($src_w,$src_h,$imagetype)=getimagesize($filename);if(is_null($dst_w)||is_null($dst_h)){$dst_w=ceil($src_w*$scale);$dst_h=ceil($src_h*$scale);}$mime=image_type_to_mime_type($imagetype);//echo $mime;//image/jpeg,image/gif$createFun=str_replace("/", "createfrom", $mime);//imagecreatefromjpeg$outFun=str_replace("/", null, $mime);//imagejpeg$src_image=$createFun($filename);$dst_image=imagecreatetruecolor($dst_w, $dst_h);imagecopyresampled($dst_image, $src_image, 0,0,0,0, $dst_w, $dst_h, $src_w, $src_h);if($destination&&!file_exists(dirname($destination))){mkdir(dirname($destination),0777,true);}$dstFilename=$destination==null?getUniName().".".getExt($filename):$destination;$outFun($dst_image,$dstFilename);imagedestroy($src_image);//销毁资源imagedestroy($dst_image);//销毁资源if(!$isReservedSource){unlink($filename);//删掉源文件}return $dstFilename;}