resize transparent image

 /** 
     *  Now with added Transparency resizing feature
     *  @param int $width
     *  @param int $height
     */
    public function resize($width,$height) 
    {
        
        $new_image = imagecreatetruecolor($width, $height);
        if ( ($this->getImageType() == IMAGETYPE_GIF) || ($this->getImageType()  == IMAGETYPE_PNG) ) 
        {
            $transparency = imagecolortransparent($this->_image);
            if ($transparency >= 0) 
            {
                $transparent_color = imagecolorsforindex($this->_image, $transparency);
                $transparency = imagecolorallocate($new_image, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue']);
                imagefill($new_image, 0, 0, $transparency);
                imagecolortransparent($new_image, $transparency);
            }
            elseif ($this->getImageType() == IMAGETYPE_PNG) 
            {
                imagealphablending($new_image, false);
                imagesavealpha($new_image, true);
                $color = imagecolorallocatealpha($new_image, 0, 0, 0, 127);
                imagefill($new_image, 0, 0, $color);
            }
        }
        imagecopyresampled($new_image, $this->_image, 0, 0, 0, 0, $width, $height, $this->getWidth(), $this->getHeight());
        $this->_image = $new_image;
    }