[examples] Update qt example

example/with_external_libs/common/read_countries.hpp

@@ -0,0 +1,66 @@
+// Boost.Geometry
+//
+// Copyright (c) 2007-2024 Barend Gehrels, Amsterdam, the Netherlands.
+// Use, modification and distribution is 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)
+
+#ifndef READ_COUNTRIES_HPP
+#define READ_COUNTRIES_HPP
+
+#include <fstream>
+#include <boost/geometry/geometry.hpp>
+
+// ----------------------------------------------------------------------------
+// Read an ASCII file containing WKT's of either POLYGON or MULTIPOLYGON
+// ----------------------------------------------------------------------------
+template <typename Geometry>
+std::vector<Geometry> read_countries(std::string const& filename)
+{
+    std::vector<Geometry> geometries;
+    std::ifstream cpp_file(filename.c_str());
+    if (!cpp_file.is_open())
+    {
+        return geometries;
+    }
+    while (! cpp_file.eof() )
+    {
+        std::string line;
+        std::getline(cpp_file, line);
+        if (line.empty())
+        {
+            continue;
+        }
+        Geometry geometry;
+        if (line.substr(0, 4) == "POLY")
+        {
+            using polygon_t = std::decay_t<decltype(*geometry.begin())>;
+            polygon_t polygon;
+            boost::geometry::read_wkt(line, polygon);
+            geometry.push_back(polygon);
+        }
+        else
+        {
+            boost::geometry::read_wkt(line, geometry);
+        }
+
+        geometries.push_back(geometry);
+    }
+    return geometries;
+}
+
+// Returns the envelope of a collection of geometries
+template <typename Box, typename Countries>
+Box calculate_envelope(Countries const& countries)
+{
+    Box box;
+    boost::geometry::assign_inverse(box);
+
+    for (auto const& country : countries)
+    {
+        boost::geometry::expand(box, boost::geometry::return_envelope<Box>(country));
+    }
+    return box;
+}
+
+#endif

example/with_external_libs/qt/CMakeLists.txt

@@ -0,0 +1,36 @@
+# Boost.Geometry
+# Example CMakeLists.txt building the Boost.Geometry with Qt example
+#
+# Copyright (c) 2021-2024 Barend Gehrels, Amsterdam, the Netherlands.
+
+# Use, modification and distribution is 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)
+
+cmake_minimum_required(VERSION 3.16)
+project(qt_world_mapper LANGUAGES CXX)
+
+find_package(Qt6 REQUIRED COMPONENTS Core Gui Widgets)
+
+qt_standard_project_setup()
+
+qt_add_executable(${PROJECT_NAME}
+    qt_world_mapper.cpp
+    qt_world_mapper.hpp
+)
+
+set_target_properties(${PROJECT_NAME} PROPERTIES
+    WIN32_EXECUTABLE TRUE
+    MACOSX_BUNDLE TRUE
+)
+
+target_link_libraries(${PROJECT_NAME} PRIVATE
+    Qt6::Core
+    Qt6::Gui
+    Qt6::Widgets
+)
+
+target_include_directories(${PROJECT_NAME} PRIVATE
+    ..
+    ../../../../..
+)

example/with_external_libs/qt/README.md

@@ -0,0 +1,61 @@
+# ![Boost.Geometry](../../../doc/other/logo/logo_bkg.png)
+
+# Qt
+
+## Introduction
+
+[Qt](https://www.qt.io/product/framework) is a stable and powerful open source framework for developing native cross-platform GUI applications in C++.
+
+## Installing Qt
+
+###  Mac
+
+On a Mac, installing Qt for this purpose is trivial:
+
+`brew install qt`
+
+And then you can use the standard CMake workflow.
+
+During that, either ignore this warning: `Could NOT find WrapVulkanHeaders (missing: Vulkan_INCLUDE_DIR)`
+
+or install vulkan-tools (`brew install vulkan-tools`), though for 2D applications, it might not be necessary.
+
+### Linux Ubuntu
+
+Install Vulkan as described [here](https://vulkan.lunarg.com/doc/sdk/1.3.239.0/linux/getting_started_ubuntu.html).
+
+Since Qt 6.3 there is `qt_standard_project_setup()` used in the `CMakeLists.txt`.
+
+If you have an older Qt version (on Ubuntu 22 you might have `QT6.2.4`), replace `qt_standard_project_setup` with:
+
+```
+set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_AUTOMOC ON)
+set(CMAKE_AUTOUIC ON)
+set(CMAKE_AUTORCC ON)
+```
+
+### Other platforms
+
+Either you have Qt installed already, or you install it according to the [Qt documentation](https://doc.qt.io/qt-6/get-and-install-qt.html),
+and change the `CMakeLists.txt` if necessary.
+
+## Building this example
+
+Assuming you want to build it with CMake, and example workflow is:
+
+```
+cd example/with_external_libs/qt
+mkdir my_build_folder
+cd my_build_folder
+cmake .. -G Ninja
+ninja
+```
+
+## Running this example
+
+You can pass an Ascii file with WKT polygons as the first command line argument. There are several
+packed with Boost.Geometry as examples and as test data.
+
+For example: `././qt_world_mapper.app/Contents/MacOS/qt_world_mapper ../../../data/world.wkt`

example/with_external_libs/qt/qt_world_mapper.cpp

@@ -0,0 +1,77 @@
+// Boost.Geometry
+//
+// Copyright (c) 2007-2024 Barend Gehrels, Amsterdam, the Netherlands.
+// Use, modification and distribution is 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)
+
+// Qt World Mapper Example
+
+#include "qt_world_mapper.hpp"
+#include "common/read_countries.hpp"
+
+#include <QApplication>
+#include <QPainter>
+#include <QTime>
+#include <QTimer>
+
+#include <boost/geometry/geometries/register/point.hpp>
+#include <boost/geometry/geometries/register/ring.hpp>
+
+// Adapt a QPointF such that it can be handled by Boost.Geometry
+BOOST_GEOMETRY_REGISTER_POINT_2D_GET_SET(QPointF, double, cs::cartesian, x, y, setX, setY)
+
+// Adapt a QPolygonF as well.
+// A QPolygonF has no holes (interiors) so it is similar to a Boost.Geometry ring
+BOOST_GEOMETRY_REGISTER_RING(QPolygonF)
+
+
+qt_world_mapper::qt_world_mapper(std::vector<country_type> const& countries, boost::geometry::model::box<point_2d> const& box, QWidget *parent)
+    : QWidget(parent)
+    , m_countries(countries)
+    , m_box(box)
+{
+    setPalette(QPalette(Qt::blue));
+    setAutoFillBackground(true);
+}
+
+void qt_world_mapper::paintEvent(QPaintEvent *)
+{
+    map_transformer_type transformer(m_box, this->width(), this->height());
+
+    QPainter painter(this);
+    painter.setBrush(Qt::green);
+    painter.setRenderHint(QPainter::Antialiasing);
+
+    for(auto const& country : m_countries)
+    {
+        for(auto const& polygon : country)
+        {
+            // This is the essention:
+            // Directly transform from a multi_polygon (ring-type) to a QPolygonF
+            QPolygonF qring;
+            boost::geometry::transform(boost::geometry::exterior_ring(polygon), qring, transformer);
+            painter.drawPolygon(qring);
+        }
+    }
+}
+
+int main(int argc, char *argv[])
+{
+    const std::string filename = argc > 1 ? argv[1] : "../../../data/world.wkt";
+    const auto countries = read_countries<country_type>(filename);
+    if (countries.empty())
+    {
+        std::cout << "No countries read" << std::endl;
+        return 1;
+    }
+
+    const auto box = calculate_envelope<boost::geometry::model::box<point_2d>>(countries);
+
+    QApplication app(argc, argv);
+    qt_world_mapper mapper(countries, box);
+    mapper.setWindowTitle("Boost.Geometry for Qt - Hello World!");
+    mapper.setGeometry(100, 100, 1024, 768);
+    mapper.show();
+    return app.exec();
+}

example/with_external_libs/qt/qt_world_mapper.hpp

@@ -0,0 +1,47 @@
+// Boost.Geometry
+//
+// Copyright (c) 2007-2024 Barend Gehrels, Amsterdam, the Netherlands.
+// Use, modification and distribution is 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)
+
+// Qt World Mapper Example
+
+#ifndef QT_WORLD_MAPPER_H
+#define QT_WORLD_MAPPER_H
+
+#include <QWidget>
+
+#include <boost/geometry/geometry.hpp>
+
+#include <boost/geometry/geometries/geometries.hpp>
+
+using point_2d = boost::geometry::model::d2::point_xy<double>;
+using country_type = boost::geometry::model::multi_polygon
+    <
+        boost::geometry::model::polygon<point_2d>
+    >;
+
+class qt_world_mapper : public QWidget
+{
+    Q_OBJECT
+
+public:
+    qt_world_mapper(std::vector<country_type> const& countries, boost::geometry::model::box<point_2d> const& box, QWidget *parent = nullptr);
+
+protected:
+    void paintEvent(QPaintEvent *event) override;
+
+private:
+    using map_transformer_type = boost::geometry::strategy::transform::map_transformer
+        <
+            double, 2, 2,
+            true, true
+        >;
+
+     std::vector<country_type> m_countries;
+     boost::geometry::model::box<point_2d> m_box;
+};
+
+
+#endif

example/with_external_libs/wxwidgets/CMakeLists.txt

@@ -11,7 +11,7 @@ cmake_minimum_required(VERSION 3.8...3.20)
 
 project(wx_widgets_world_mapper)
 
-add_executable(${PROJECT_NAME} x04_wxwidgets_world_mapper.cpp)
+add_executable(${PROJECT_NAME} wxwidgets_world_mapper.cpp)
 target_compile_features(${PROJECT_NAME} PUBLIC cxx_std_14)
 
 # Link the wxWidgets libraries to our executable
@@ -21,7 +21,7 @@ target_link_libraries(${PROJECT_NAME} wxWidgets::wxWidgets)
 
 # Link the Boost.Geometry library to our executable
 # By default, it is assumed to be relative to this directory.
-target_include_directories(${PROJECT_NAME} PRIVATE ../../../../..)
+target_include_directories(${PROJECT_NAME} PRIVATE .. ../../../../..)
 
 # If this does not work, or you build from elsewhere
 # First set BOOST_ROOT

example/with_external_libs/wxwidgets/x04_wxwidgets_world_mapper.cpp → example/with_external_libs/wxwidgets/wxwidgets_world_mapper.cpp

@@ -13,7 +13,6 @@
 
 // #define EXAMPLE_WX_USE_GRAPHICS_CONTEXT 1
 
-#include <fstream>
 #include <sstream>
 
 #include <boost/geometry/geometry.hpp>
@@ -34,6 +33,8 @@
 #include "wx/dcgraph.h"
 #endif
 
+#include "common/read_countries.hpp"
+
 using point_2d = boost::geometry::model::d2::point_xy<double>;
 using country_type = boost::geometry::model::multi_polygon
     <
@@ -45,41 +46,6 @@ using country_type = boost::geometry::model::multi_polygon
 BOOST_GEOMETRY_REGISTER_POINT_2D(wxPoint, int, cs::cartesian, x, y)
 BOOST_GEOMETRY_REGISTER_POINT_2D(wxRealPoint, double, cs::cartesian, x, y)
 
-// ----------------------------------------------------------------------------
-// Read an ASCII file containing WKT's of either POLYGON or MULTIPOLYGON
-// ----------------------------------------------------------------------------
-template <typename Geometry, typename Box>
-inline void read_wkt(std::string const& filename, std::vector<Geometry>& geometries, Box& box)
-{
-    std::ifstream cpp_file(filename.c_str());
-    if (cpp_file.is_open())
-    {
-        while (! cpp_file.eof() )
-        {
-            std::string line;
-            std::getline(cpp_file, line);
-            if (line.empty())
-            {
-                continue;
-            }
-            Geometry geometry;
-            if (line.substr(0, 4) == "POLY")
-            {
-                boost::geometry::model::polygon<point_2d> polygon;
-                boost::geometry::read_wkt(line, polygon);
-                geometry.push_back(polygon);
-            }
-            else
-            {
-                boost::geometry::read_wkt(line, geometry);
-            }
-
-            geometries.push_back(geometry);
-            boost::geometry::expand(box, boost::geometry::return_envelope<Box>(geometry));
-        }
-    }
-}
-
 
 // ----------------------------------------------------------------------------
 class HelloWorldFrame: public wxFrame
@@ -195,8 +161,8 @@ HelloWorldCanvas::HelloWorldCanvas(wxFrame *frame, const std::string& filename)
     , m_owner(frame)
     , m_filename(filename)
 {
-    boost::geometry::assign_inverse(m_box);
-    read_wkt(m_filename, m_countries, m_box);
+    m_countries = read_countries<country_type>(m_filename);
+    m_box = calculate_envelope<boost::geometry::model::box<point_2d>>(m_countries);
 }