void set_color (uint32_t);
bool color_out_of_bounds() const { return _color == out_of_bound_color; }
static const uint32_t out_of_bound_color;
void set_color (uint32_t);
bool color_out_of_bounds() const { return _color == out_of_bound_color; }
static const uint32_t out_of_bound_color;