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Point concept.
A legacy point, defining the necessary specializations to fulfil to the concept.
Suppose that the following point is defined:
struct legacy_point1 { double x, y; };
It can then be adapted to the concept as following:
// adapt legacy_point1 namespace boost { namespace geometry { namespace traits { template <> struct tag<legacy_point1> { typedef point_tag type; }; template <> struct coordinate_type<legacy_point1> { typedef double type; }; template <> struct coordinate_system<legacy_point1> { typedef cs::cartesian type; }; template <> struct dimension<legacy_point1>: boost::mpl::int_<2> {}; template <> struct access<legacy_point1, 0> { static double get(legacy_point1 const& p) { return p.x; } static void set(legacy_point1& p, double const& value) { p.x = value; } }; template <> struct access<legacy_point1, 1> { static double get(legacy_point1 const& p) { return p.y; } static void set(legacy_point1& p, double const& value) { p.y = value; } }; }}} // namespace boost::geometry::traits
Note that it is done like above to show the system. Users will normally use the registration macro.
A read-only legacy point, using a macro to fulfil to the ConstPoint concept. It cannot be modified by the library but can be used in all algorithms where points are not modified.
The point looks like the following:
class legacy_point2 { public : double x() const; double y() const; };
It uses the macro as following:
// adapt legacy_point2 BOOST_GEOMETRY_REGISTER_POINT_2D_CONST(legacy_point2, double, boost::geometry::cs::cartesian, x(), y() ) // end adaptation
April 2, 2011 |
Copyright © 2007-2011 Barend Gehrels, Amsterdam, the Netherlands Copyright © 2008-2011 Bruno Lalande, Paris, France Copyright © 2009-2010 Mateusz Loskot, London, UK |