(C++) BoostGeometryExample2

 

 

Boost.Geometry example 2: points to polygon and back, determine the area of a polygon is a Boost.Geometry example.

Technical facts

 

Application type(s)

• Desktop application

Operating system(s) or programming environment(s)

• Lubuntu 15.04 (vivid)

IDE(s):

• Qt Creator 3.1.1

Project type:

• GUI application

C++ standard:

• C++11

Compiler(s):

• G++ 4.9.2

Libraries used:

• Qt: version 5.4.1 (32 bit)
• STL: GNU ISO C++ Library, version 4.9.2

 

 

 

 

 

Qt project file: ./CppBoostGeometryExample2/CppBoostGeometryExample2.pro

 

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exists(../../ConsoleApplication.pri) {   include(../../ConsoleApplication.pri) } !exists(../../ConsoleApplication.pri) {   QT += core   QT += gui   greaterThan(QT_MAJOR_VERSION, 4): QT += widgets   CONFIG   += console   CONFIG   -= app_bundle   TEMPLATE = app   CONFIG(release, debug|release) {     DEFINES += NDEBUG NTRACE_BILDERBIKKEL   }   QMAKE_CXXFLAGS += -std=c++11 -Wall -Wextra -Weffc++   unix {     QMAKE_CXXFLAGS += -Werror   } } exists(../../Libraries/Boost.pri) {   include(../../Libraries/Boost.pri) } !exists(../../Libraries/Boost.pri) {   win32 {     INCLUDEPATH += \       ../../Libraries/boost_1_55_0   } } SOURCES += main.cpp

 

 

 

 

 

./CppBoostGeometryExample2/main.cpp

 

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#include <cassert> #include <iostream> #pragma GCC diagnostic push #pragma GCC diagnostic ignored "-Weffc++" #pragma GCC diagnostic ignored "-Wunused-local-typedefs" #pragma GCC diagnostic ignored "-Wunused-variable" #include <boost/geometry.hpp> #include <boost/geometry/geometries/point_xy.hpp> #include <boost/geometry/geometries/ring.hpp> //#include <boost/geometry/geometries/adapted/std_as_ring.hpp> //Is absent in 1.54.0 #pragma GCC diagnostic pop int main() {   typedef boost::geometry::model::d2::point_xy<double> Coordinat2D;   /* Polygon used:     3-      |     2-    0 #      |   / \     1-  4   1      |  | * |     0-  3---2      |      +--|---|---|         0   1   2   *: point that is tested to be within the polygon   #: point that is tested to be outside of the polygon   */   const std::vector<Coordinat2D> points {     {0.5, 2.0}, //0     {1.0, 1.0}, //1     {1.0, 0.0}, //2     {0.0, 0.0}, //3     {0.0, 1.0}  //4   };   boost::geometry::model::polygon<Coordinat2D> house;   boost::geometry::append(house, points);   boost::geometry::model::ring<Coordinat2D> points_again;   boost::geometry::convert(house,points_again);   //Instead of using this syntax:   //  assert(points == points_again);   //operator== needs to be defined, which is done by a lambda function   assert(     std::equal(       points.begin(),points.end(),       points_again.begin(),       [](const Coordinat2D& a,const Coordinat2D& b)       {         return boost::geometry::equals(a,b);       }     )   );   assert( boost::geometry::within(Coordinat2D(0.5, 0.5), house));   assert(!boost::geometry::within(Coordinat2D(1.0, 2.0), house));   const double area = boost::geometry::area(house);   std::cout << "Area: " << area << std::endl; }