AxisFixed::Grid PHP Méthode

    public function Grid($min, $round_up = false)
    {
        // if min and max are the same side of 0, only adjust one of them
        if ($this->max_value * $this->min_value >= 0) {
            $count = $this->max_value - $this->min_value;
            // $round_up means bars, so add space for the bar
            if ($round_up) {
                ++$count;
            }
            if (abs($this->max_value) >= abs($this->min_value)) {
                $this->max_value = $this->min_value + $this->step * ceil($count / $this->step);
            } else {
                $this->min_value = $this->max_value - $this->step * ceil($count / $this->step);
            }
        } else {
            $this->max_value = $this->step * ceil($this->max_value / $this->step);
            $this->min_value = $this->step * floor($this->min_value / $this->step);
        }
        $count = ($this->max_value - $this->min_value) / $this->step;
        $ulen = $this->max_value - $this->min_value;
        if ($ulen == 0) {
            throw new Exception("Zero length axis");
        }
        $this->unit_size = $this->length / $ulen;
        $grid = $this->length / $count;
        $this->zero = -$this->min_value / $this->step * $grid;
        return $grid;
    }