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Usage

[TOC]

MapLibre Native can be used with Qt either with C++ or with QML. The following sections will guide you through the process of setting up a project and using MapLibre Native with it.

Examples

Two example apps are provided for Qt 6 in the examples directory of the repository:

  • quick is a QML app that uses the MapView QML type.
  • widgets is a C++ app that uses the QMapLibre::GLWidget widget.
export QMapLibre_DIR="<absolute-path-to-install>"
cmake --workflow --preset default

or alternatively

mkdir build-example && cd build-example
qt-cmake ../maplibre-native-qt/examples/<example> -GNinja \
  -DCMAKE_C_COMPILER_LAUNCHER="ccache" \
  -DCMAKE_CXX_COMPILER_LAUNCHER="ccache" \
  -DCMAKE_PREFIX_PATH="<absolute-path-to-install>"
ninja

Basic CMake setup

To use MapLibre Native in a Qt project built with CMake you can use the find_package command to locate the package QMapLibre and then link the target to the QMapLibre::Core, QMapLibre::Location or QMapLibre::Widgets targets. Only specific components can be looked for by using the COMPONENTS option. For example, to use the Widgets component you need to add the following lines to your CMakeLists.txt:

find_package(QMapLibre COMPONENTS Widgets REQUIRED)

target_link_libraries(
    MyApplication
    PRIVATE
        QMapLibre::Widgets
)

There are multiple options to make CMake find the package:

  • set the QMapLibre_DIR variable to the directory where the package is installed ending with <path>/lib/cmake/QMapLibre
  • set the CMAKE_PREFIX_PATH variable to the directory where the package is installed

Widgets setup

No special additional setup is needed. QMapLibre and QMapLibreWidgets libraries need to be provided with your application.

QML setup

To use MapLibre Native in a QML project you need to ensure that the plugins are installed with your application:

  • plugins/geoservices for the mapping engine itself
  • qml/MapLibre for the QML types

Of course also QMapLibre and QMapLibreLocation libraries need to be provided with your application.

This can be ensured automatically using the helper function qmaplibre_location_setup_plugins(<target>) which is available once MapLibre Native is found by CMake.

@warning Only OpenGL backend is supported for now!

For example, to use MapLibre in a CMake-based QML project you need to add

find_package(QMapLibre COMPONENTS Location REQUIRED)

target_link_libraries(
    MyApplication
    PRIVATE
        QMapLibre::Location
)

qmaplibre_location_setup_plugins(MyApplication)

Development specifics

Once your application is deployed there should be no special environment or other overrides needed to run the application. However, during development you may need to set some environment variables:

  • QSG_RHI_BACKEND=opengl to force the OpenGL backend
  • DYLD_LIBRARY_PATH to find libraries on macOS
  • LD_LIBRARY_PATH to find libraries on Linux
  • QML_IMPORT_PATH=<installation-path>/qml to find the QML types (QML2_IMPORT_PATH for Qt 5)
  • QT_PLUGIN_PATH=<installation-path>plugins to find the plugins

Platform specifics

Android

For Android multi-ABI builds you need to ensure that the correct build is picked-up. In CMake this can be done like

if(ANDROID AND DEFINED ENV{QMapLibre_Android_DIR})
    message(STATUS "Setting QMapLibre_DIR to $ENV{QMapLibre_Android_DIR}/${ANDROID_ABI}/lib/cmake/QMapLibre")
    set(QMapLibre_DIR "$ENV{QMapLibre_Android_DIR}/${ANDROID_ABI}/lib/cmake/QMapLibre")
endif()
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