Polygon Set Usage

/*
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>
namespace gtl = boost::polygon;
using namespace boost::polygon::operators;
int main() {
//lets declare ourselves a polygon set
using namespace gtl; //because of operators
typedef std::vector<polygon_data<int> > PolygonSet;
PolygonSet ps;
//lets put some data in
ps += rectangle_data<int>(0, 0, 10, 10);
//now lets do something interesting
PolygonSet ps2;
ps2 += rectangle_data<int>(5, 5, 15, 15);
PolygonSet ps3;
assign(ps3, ps * ps2); //woah, I just felt the room flex around me
PolygonSet ps4;
ps4 += ps + ps2;
//assert that area of result is equal to sum of areas
//of input geometry minus the area of overlap between inputs
assert(area(ps4) == area(ps) + area(ps2) - area(ps3));
//I don't even see the code anymore, all
//I see is bounding box...interval...triangle
//lets try that again in slow motion shall we?
assert(equivalence((ps + ps2) - (ps * ps2), ps ^ ps2));
//hmm, subtracting the intersection from the union
//is equivalent to the xor, all this in one line of code,
//now we're programming in bullet time
//(by the way, xor is implemented as one pass, not composition)
//just for fun
rectangle_data<int> rect;
assert(extents(rect, ps ^ ps2));
assert(area(rect) == 225);
assert(area(rect ^ (ps ^ ps2)) == area(rect) - area(ps ^ ps2));
return 0;
}
//Now you know how to use the polygon set concept with library polygons

Copyright: | Copyright © Intel Corporation 2008-2010.
License: | Distributed under 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)