2 some 2D geometrical concepts
13 Interval interval_a_[NO_AXES];
15 Interval &x () {return interval_a_[X_AXIS]; }
16 Interval &y (){ return interval_a_[Y_AXIS]; }
17 Interval x () const{ return interval_a_[X_AXIS]; }
18 Interval y () const{return interval_a_[Y_AXIS]; }
19 Interval operator [] (Axis a) const;
20 Interval &operator [] (Axis a);
22 Offset center () const;
24 void translate (Offset o);
25 /// smallest box enclosing #b#
27 void add_point (Offset);
28 void widen (Real x, Real y);
32 Box (Interval ix, Interval iy);