libs/geometry/test/algorithms/test_simplify.hpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2 // Unit Test
   3
   4 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
   5 // Use, modification and distribution is subject to the Boost Software License,
   6 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   7 // http://www.boost.org/LICENSE_1_0.txt)
   8
   9 #ifndef BOOST_GEOMETRY_TEST_SIMPLIFY_HPP
  10 #define BOOST_GEOMETRY_TEST_SIMPLIFY_HPP
  11
  12 // Test-functionality, shared between single and multi tests
  13
  14 #include <geometry_test_common.hpp>
  15 #include <boost/geometry/algorithms/simplify.hpp>
  16 #include <boost/geometry/algorithms/distance.hpp>
  17 #include <boost/geometry/strategies/strategies.hpp>
  18
  19 #include <boost/geometry/io/wkt/wkt.hpp>
  20
  21 template <typename Tag, typename Geometry>
  22 struct test_inserter
  23 {
  24     static void apply(Geometry& , std::string const& , double )
  25     {}
  26 };
  27
  28 template <typename Geometry>
  29 struct test_inserter<bg::linestring_tag, Geometry>
  30 {
  31     static void apply(Geometry& geometry, std::string const& expected, double distance)
  32     {
  33         Geometry simplified;
  34         bg::detail::simplify::simplify_insert(geometry,
  35             std::back_inserter(simplified), distance);
  36
  37         std::ostringstream out;
  38         out << bg::wkt(simplified);
  39         BOOST_CHECK_EQUAL(out.str(), expected);
  40     }
  41 };
  42
  43
  44 template <typename Geometry>
  45 void test_geometry(std::string const& wkt, std::string const& expected, double distance)
  46 {
  47     Geometry geometry, simplified;
  48
  49     // Generate polygon using only integer coordinates and obvious results
  50     // Polygon is a hexagon, having one extra point (2,1) on a line which should be filtered out.
  51     bg::read_wkt(wkt, geometry);
  52     bg::simplify(geometry, simplified, distance);
  53
  54     {
  55         std::ostringstream out;
  56         out << bg::wkt(simplified);
  57
  58         BOOST_CHECK_MESSAGE(out.str() == expected,
  59             "simplify: " << bg::wkt(geometry)
  60             << " expected " << expected
  61             << " got " << bg::wkt(simplified));
  62     }
  63
  64     // Check using user-specified strategy
  65     typedef typename bg::point_type<Geometry>::type point_type;
  66     typedef typename bg::cs_tag<point_type>::type tag;
  67     typedef bg::strategy::distance::projected_point
  68         <
  69             point_type,
  70             point_type
  71         > strategy;
  72     typedef bg::strategy::simplify::douglas_peucker
  73         <
  74             point_type,
  75             strategy
  76         > simplify_strategy_type;
  77
  78     BOOST_CONCEPT_ASSERT( (bg::concept::SimplifyStrategy<simplify_strategy_type>) );
  79     bg::simplify(geometry, simplified, distance, simplify_strategy_type());
  80
  81     {
  82         std::ostringstream out;
  83         out << bg::wkt(simplified);
  84         BOOST_CHECK_EQUAL(out.str(), expected);
  85     }
  86
  87     // Check inserter (if applicable)
  88     test_inserter
  89         <
  90             typename bg::tag<Geometry>::type,
  91             Geometry
  92         >::apply(geometry, expected, distance);
  93 }
  94
  95
  96 #endif