/Src/Dependencies/Boost/libs/geometry/doc/src/examples/core/rings.cpp
http://hadesmem.googlecode.com/ · C++ · 77 lines · 31 code · 18 blank · 28 comment · 0 complexity · d58da1b47cd7918d308279d2e1f7e5b6 MD5 · raw file
- // Boost.Geometry (aka GGL, Generic Geometry Library)
- // QuickBook Example
- // Copyright (c) 2011 Barend Gehrels, Amsterdam, the Netherlands.
- // Use, modification and distribution is subject to the Boost Software License,
- // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- //[rings
- /*`
- Shows how to access the exterior ring (one)
- and interior rings (zero or more) of a polygon.
- Also shows the related ring_type and interior_type.
- */
- #include <iostream>
- #include <boost/geometry.hpp>
- #include <boost/geometry/geometries/polygon.hpp>
- #include <boost/geometry/geometries/point_xy.hpp>
- int main()
- {
- typedef boost::geometry::model::d2::point_xy<double> point;
- typedef boost::geometry::model::polygon<point> polygon_type;
- polygon_type poly;
-
- typedef boost::geometry::ring_type<polygon_type>::type ring_type;
- ring_type& ring = boost::geometry::exterior_ring(poly);
-
- // For a ring of model::polygon, you can call "push_back".
- // (internally, it is done using a traits::push_back class)
- ring.push_back(point(0, 0));
- ring.push_back(point(0, 5));
- ring.push_back(point(5, 4));
- ring.push_back(point(0, 0));
-
- ring_type inner;
- inner.push_back(point(1, 1));
- inner.push_back(point(2, 1));
- inner.push_back(point(2, 2));
- inner.push_back(point(1, 1));
- typedef boost::geometry::interior_type<polygon_type>::type int_type;
- int_type& interiors = boost::geometry::interior_rings(poly);
- interiors.push_back(inner);
- std::cout << boost::geometry::dsv(poly) << std::endl;
-
- // So int_type defines a collection of rings,
- // which is a Boost.Range compatible range
- // The type of an element of the collection is the very same ring type again.
- // We show that.
- typedef boost::range_value<int_type>::type int_ring_type;
-
- std::cout
- << std::boolalpha
- << boost::is_same<ring_type, int_ring_type>::value
- << std::endl;
- return 0;
- }
- //]
- //[rings_output
- /*`
- Output:
- [pre
- (((0, 0), (0, 5), (5, 4), (0, 0)), ((1, 1), (2, 1), (2, 2), (1, 1)))
- true
- ]
- */
- //]