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- /*
- Copyright 2008 Intel Corporation
- Use, modification and distribution are 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).
- */
- #include <boost/polygon/polygon.hpp>
- #include <cassert>
- #include <list>
- namespace gtl = boost::polygon;
- using namespace boost::polygon::operators;
- //first lets turn our polygon usage code into a generic
- //function parameterized by polygon type
- template <typename Polygon>
- void test_polygon() {
- //lets construct a 10x10 rectangle shaped polygon
- typedef typename gtl::polygon_traits<Polygon>::point_type Point;
- Point pts[] = {gtl::construct<Point>(0, 0),
- gtl::construct<Point>(10, 0),
- gtl::construct<Point>(10, 10),
- gtl::construct<Point>(0, 10) };
- Polygon poly;
- gtl::set_points(poly, pts, pts+4);
- //now lets see what we can do with this polygon
- assert(gtl::area(poly) == 100.0f);
- assert(gtl::contains(poly, gtl::construct<Point>(5, 5)));
- assert(!gtl::contains(poly, gtl::construct<Point>(15, 5)));
- gtl::rectangle_data<int> rect;
- assert(gtl::extents(rect, poly)); //get bounding box of poly
- assert(gtl::equivalence(rect, poly)); //hey, that's slick
- assert(gtl::winding(poly) == gtl::COUNTERCLOCKWISE);
- assert(gtl::perimeter(poly) == 40.0f);
- //add 5 to all coords of poly
- gtl::convolve(poly, gtl::construct<Point>(5, 5));
- //multiply all coords of poly by 2
- gtl::scale_up(poly, 2);
- gtl::set_points(rect, gtl::point_data<int>(10, 10),
- gtl::point_data<int>(30, 30));
- assert(gtl::equivalence(poly, rect));
- }
- //Now lets declare our own polygon class
- //Oops, we need a point class to support our polygon, lets borrow
- //the CPoint example
- struct CPoint {
- int x;
- int y;
- };
- //we have to get CPoint working with boost polygon to make our polygon
- //that uses CPoint working with boost polygon
- namespace boost { namespace polygon {
- template <>
- struct geometry_concept<CPoint> { typedef point_concept type; };
- template <>
- struct point_traits<CPoint> {
- typedef int coordinate_type;
- static inline coordinate_type get(const CPoint& point,
- orientation_2d orient) {
- if(orient == HORIZONTAL)
- return point.x;
- return point.y;
- }
- };
- template <>
- struct point_mutable_traits<CPoint> {
- typedef int coordinate_type;
- static inline void set(CPoint& point, orientation_2d orient, int value) {
- if(orient == HORIZONTAL)
- point.x = value;
- else
- point.y = value;
- }
- static inline CPoint construct(int x_value, int y_value) {
- CPoint retval;
- retval.x = x_value;
- retval.y = y_value;
- return retval;
- }
- };
- } }
- //I'm lazy and use the stl everywhere to avoid writing my own classes
- //my toy polygon is a std::list<CPoint>
- typedef std::list<CPoint> CPolygon;
- //we need to specialize our polygon concept mapping in boost polygon
- namespace boost { namespace polygon {
- //first register CPolygon as a polygon_concept type
- template <>
- struct geometry_concept<CPolygon>{ typedef polygon_concept type; };
- template <>
- struct polygon_traits<CPolygon> {
- typedef int coordinate_type;
- typedef CPolygon::const_iterator iterator_type;
- typedef CPoint point_type;
- // Get the begin iterator
- static inline iterator_type begin_points(const CPolygon& t) {
- return t.begin();
- }
- // Get the end iterator
- static inline iterator_type end_points(const CPolygon& t) {
- return t.end();
- }
- // Get the number of sides of the polygon
- static inline std::size_t size(const CPolygon& t) {
- return t.size();
- }
- // Get the winding direction of the polygon
- static inline winding_direction winding(const CPolygon& t) {
- return unknown_winding;
- }
- };
- template <>
- struct polygon_mutable_traits<CPolygon> {
- //expects stl style iterators
- template <typename iT>
- static inline CPolygon& set_points(CPolygon& t,
- iT input_begin, iT input_end) {
- t.clear();
- t.insert(t.end(), input_begin, input_end);
- return t;
- }
- };
- } }
- //now there's nothing left to do but test that our polygon
- //works with library interfaces
- int main() {
- test_polygon<CPolygon>(); //woot!
- return 0;
- }
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