PieGraph::Calc PHP Method

    protected function Calc()
    {
        $bound_x_left = $this->pad_left;
        $bound_y_top = $this->pad_top;
        $bound_x_right = $this->width - $this->pad_right;
        $bound_y_bottom = $this->height - $this->pad_bottom;
        $w = $bound_x_right - $bound_x_left;
        $h = $bound_y_bottom - $bound_y_top;
        if ($this->aspect_ratio == 'auto') {
            $this->aspect_ratio = $h / $w;
        } elseif ($this->aspect_ratio <= 0) {
            $this->aspect_ratio = 1.0;
        }
        $this->x_centre = ($bound_x_right - $bound_x_left) / 2 + $bound_x_left;
        $this->y_centre = ($bound_y_bottom - $bound_y_top) / 2 + $bound_y_top;
        $this->start_angle %= 360;
        if ($this->start_angle < 0) {
            $this->start_angle = 360 + $this->start_angle;
        }
        $this->s_angle = deg2rad($this->start_angle);
        if ($h / $w > $this->aspect_ratio) {
            $this->radius_x = $w / 2.0;
            $this->radius_y = $this->radius_x * $this->aspect_ratio;
        } else {
            $this->radius_y = $h / 2.0;
            $this->radius_x = $this->radius_y / $this->aspect_ratio;
        }
        $this->calc_done = true;
    }

 /**
  * Calculates reduced radius of pie
  */
 protected function Calc()
 {
     parent::Calc();
     $this->explode_amount = min($this->radius_x - 10, $this->radius_y - 10, max(2, (int) $this->explode_amount));
     $this->radius_y -= $this->explode_amount;
     $this->radius_x -= $this->explode_amount;
 }