php調整gif動畫圖片尺寸示例代碼分享

 這篇文章主要介紹了如何使用php調整gif動畫圖片尺寸，大家可以參考使用

類的使用demo：     代碼如下: <?php  require_once "roucheng.php";   $gr = new gifresizer;  $gr->temp_dir = "keleyi";  $gr->resize("keleyi.gif","keleyi_resized.gif",500,500);  ?>     類的源代碼,保存為roucheng.php文件：     代碼如下: <?      /**      *      * Resizes Animated GIF Files     *     *   ///IMPORTANT NOTE: The script needs a temporary directory where all the frames should be extracted.      *   Create a directory with a 777 permission level and write the path into $temp_dir variable below.      *        *   Default directory is "frames".     */       class gifresizer {           public $temp_dir = "frames";         private $pointer = 0;         private $index = 0;         private $globaldata = array();         private $imagedata = array();         private $imageinfo = array();         private $handle = 0;         private $orgvars = array();         private $encdata = array();         private $parsedfiles = array();         private $originalwidth = 0;         private $originalheight = 0;         private $wr,$hr;         private $props = array();         private $decoding = false;           /**          * Public part of the class         *          * @orgfile - Original file path         * @newfile - New filename with path         * @width   - Desired image width          * @height  - Desired image height         */         function resize($orgfile,$newfile,$width,$height){             $this->decode($orgfile);             $this->wr=$width/$this->originalwidth;             $this->hr=$height/$this->originalheight;             $this->resizeframes();             $this->encode($newfile,$width,$height);             $this->clearframes();         }              /**          * GIF Decoder function.         * Parses the GIF animation into single frames.         */         private function decode($filename){             $this->decoding = true;                         $this->clearvariables();             $this->loadfile($filename);             $this->get_gif_header();             $this->get_graphics_extension(0);             $this->get_application_data();             $this->get_application_data();             $this->get_image_block(0);             $this->get_graphics_extension(1);             $this->get_comment_data();             $this->get_application_data();             $this->get_image_block(1);             while(!$this->checkbyte(0x3b) && !$this->checkEOF()){                 $this->get_comment_data(1);                 $this->get_graphics_extension(2);                 $this->get_image_block(2);             }             $this->writeframes(time());                   $this->closefile();             $this->decoding = false;         }           /**          * GIF Encoder function.         * Combines the parsed GIF frames into one single animation.         */         private function encode($new_filename,$newwidth,$newheight){             $mystring = "";             $this->pointer = 0;             $this->imagedata = array();             $this->imageinfo = array();             $this->handle = 0;             $this->index=0;               $k=0;             foreach($this->parsedfiles as $imagepart){                 $this->loadfile($imagepart);                 $this->get_gif_header();                 $this->get_application_data();                 $this->get_comment_data();                 $this->get_graphics_extension(0);                 $this->get_image_block(0);                   //get transparent color index and color                 if(isset($this->encdata[$this->index-1]))                     $gxdata = $this->encdata[$this->index-1]["graphicsextension"];                 else                     $gxdata = null;                 $ghdata = $this->imageinfo["gifheader"];                 $trcolor = "";                 $hastransparency=($gxdata[3]&&1==1);                   if($hastransparency){                     $trcx = ord($gxdata[6]);                     $trcolor = substr($ghdata,13+$trcx*3,3);                 }                   //global color table to image data;                 $this->transfercolortable($this->imageinfo["gifheader"],$this->imagedata[$this->index-1]["imagedata"]);                    $imageblock = &$this->imagedata[$this->index-1]["imagedata"];                   //if transparency exists transfer transparency index                 if($hastransparency){             &n