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69 lines
1.7 KiB
C++
69 lines
1.7 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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// QuickBook Example
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// Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands.
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//[for_each_point
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//` Convenient usage of for_each_point, rounding all points of a geometry
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#include <iostream>
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#include <boost/geometry.hpp>
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#include <boost/geometry/geometries/point_xy.hpp>
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#include <boost/geometry/geometries/polygon.hpp>
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template <typename Point>
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class round_coordinates
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{
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private :
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typedef typename boost::geometry::coordinate_type<Point>::type coordinate_type;
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coordinate_type factor;
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inline coordinate_type round(coordinate_type value)
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{
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return floor(0.5 + (value / factor)) * factor;
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}
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public :
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round_coordinates(coordinate_type f)
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: factor(f)
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{}
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inline void operator()(Point& p)
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{
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using boost::geometry::get;
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using boost::geometry::set;
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set<0>(p, round(get<0>(p)));
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set<1>(p, round(get<1>(p)));
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}
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};
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int main()
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{
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typedef boost::geometry::model::d2::point_xy<double> point;
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boost::geometry::model::polygon<point> poly;
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boost::geometry::read_wkt("POLYGON((0 0,1.123 9.987,8.876 2.234,0 0),(3.345 4.456,7.654 8.765,9.123 5.432,3.345 4.456))", poly);
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boost::geometry::for_each_point(poly, round_coordinates<point>(0.1));
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std::cout << "Rounded: " << boost::geometry::wkt(poly) << std::endl;
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return 0;
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}
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//]
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//[for_each_point_output
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/*`
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Output:
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[pre
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Rounded: POLYGON((0 0,1.1 10,8.9 2.2,0 0),(3.3 4.5,7.7 8.8,9.1 5.4,3.3 4.5))
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]
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*/
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//]
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