(C++) BoostGeometryExample13

 

Boost.Geometry example 13: Convert a polygon to linestring and back 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: ./CppBoostGeometryExample13/CppBoostGeometryExample13.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

 

 

 

 

 

./CppBoostGeometryExample13/main.cpp

 

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#include <cassert> #include <iostream> #include <vector> #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/algorithms/equals.hpp> #include <boost/geometry/geometries/point_xy.hpp> #include <boost/geometry/geometries/polygon.hpp> #include <boost/geometry/geometries/linestring.hpp> #include <boost/geometry/io/wkt/read.hpp> #pragma GCC diagnostic pop //Convert a polygon to linestring and back int main() {   typedef boost::geometry::model::d2::point_xy<double> Point;   typedef boost::geometry::model::linestring<Point> Linestring;   typedef boost::geometry::model::polygon<Point> Polygon;   //Create polygon   Polygon polygon;   boost::geometry::read_wkt(     "POLYGON((1.0 1.0, 1.0 3.0, 3.0 3.0, 3.0 1.0))",     polygon   );   //Convert polygon to linestring   Linestring linestring;   boost::geometry::append(linestring, polygon.outer());   //Convert linestring to new polygon   Polygon new_polygon;   boost::geometry::append(new_polygon, linestring);   //Check that the resulting polygon equals the original   //Instead of using this syntax:   //  assert(polygon == new_polygon);   //operator== needs to be defined, which is done by a lambda function   assert(     std::equal(       polygon.outer().begin(),polygon.outer().end(),       new_polygon.outer().begin(),       [](const Point& a, const Point& b)       {         return boost::geometry::equals(a,b);       }     )   ); }