搞了两天，没有弄成，宣布失败，求高手帮忙！

class RoundedCorner {  

    private $_r;  

    private $_g;  

    private $_b;  

    private $_image_path;  

    private $_radius;  

      

   function __construct($image_path, $radius, $r = 255, $g = 255, $b = 255) {   

        $this->_image_path = $image_path;  

        $this->_radius = $radius;  

        $this->_r = (int)$r;  

        $this->_g = (int)$g;  

        $this->_b = (int)$b;  

    }  

      

    private function _get_lt_rounder_corner() {  

        $radius = $this->_radius;  

        $img = imagecreatetruecolor($radius, $radius);  

        $bgcolor = imagecolorallocate($img, $this->_r, $this->_g, $this->_b);  

        $fgcolor = imagecolorallocate($img, 0, 0, 0);  

        imagefill($img, 0, 0, $bgcolor);  

        imagefilledarc($img, $radius, $radius, $radius*2, $radius*2, 180, 270, $fgcolor, IMG_ARC_PIE);  

        imagecolortransparent($img, $fgcolor);  

        return $img;  

    }  

      

    private function _load_source_image() {  

        $ext = substr($this->_image_path, strrpos($this->_image_path, '.'));  

        if (empty($ext)) {  

            return false;