.. _build_cmake:

===== CMake

Overview

CMake is a cross-platform build system generator. It is used to easily integrate a project/library into another project. It also offers the possibility to configure the build with different options, to enable or disable components, or to integrate custom scripts executions during the configuration/build phase.

LVGL includes CMake natively, which means that one can use it to configure and build LVGL directly or integrate it into a higher level cmake build.

This project uses CMakePresets to ensure an easy build. Find out more on Cmake Presets here: https://cmake.org/cmake/help/latest/manual/cmake-presets.7.html

Prerequisites

You need to install

CMake with GNU make or Ninja (for Linux builds). Be sure to add ninja/make to your PATH!
The prerequisites listed in scripts/install-prerequisites.sh/bat
A python3 interpreter if you wish to use KConfig.

How to build this project using cmake

Build with Command line


The simplest way to build LVGL using cmake is to use the command line calls:

.. code-block:: bash

    # Method 1
    cd <lvgl_repo>
    mkdir build
    cd build
    cmake ..            # Configure phase
    cmake --build .     # Build phase

    # Method 2
    cd <lvgl_repo>
    cmake -B build      # Configure phase
    cmake --build build # build phase


Build with cmake presets

Another way to build this project is to use the provided CMakePresets.json or pass options using the command line. The CMakePresets.json file describes some cmake configurations and build phase. It is a way to quickly use a set of predefined cmake options.

For now, these configuration presets are available:

windows-base: A Windows configuration, using VS MSVC. Uses lv_conf.h as the configuration system.
windows-kconfig: A Windows configuration, using VS MSVC. Uses Kconfig as the configuration system.
linux-base: A Linux configuration, using Ninja and GCC. Uses lv_conf.h as the configuration system.
linux-kconfig: A Linux configuration, using Ninja and GCC. Uses Kconfig as the configuration system.

And these build presets:

windows-base_dbg: Windows Debug build.
windows-base_rel: Windows Release build.
linux-base_dbg: Linux Debug build.
linux-base_rel: Linux Release build.

Here is how to build using the presets:

.. code-block:: bash

cmake --preset windows-base
cmake --build --preset windows-base_dbg
ctest --preset windows-base_dbg

Build with IDE


The recommended way for consuming CMakePresets is a CMakePresets aware IDE such as

- VS 2022
- VS Code
- CLion


Simply load this project into your IDE and select your desired preset and you are good to go.


Build with CMake GUI

Open this project with CMake GUI and select your desired preset. When hitting the generate button, CMake will create solution files (for VS) or Ninja Files (for Linux Ninja Build)

The following targets are available.

lvgl (the actual library, required)
lvgl_thorvg (a vector graphics extension, optional)
lvgl_examples (example usages, optional)
lvgl_demos (some demos, optional)

All optional targets can be disabled by setting the proper cache variables. If you use cmake to install lvgl, 3 folders will be created.

include/lvgl (contains all public headers)
bin (contains all binaries (*.dll))
lib (contains all precompiled source files (*.lib))

.. _integrating_lvgl_cmake:

Integrate LVGL to your project using cmake

The LVGL cmake system is made to be integrated into higher level projects. To do so, simply add this to your project's CMakeLists.txt.

This snippet adds LVGL and needs an lv_conf.h file present next to the lvgl folder:

.. code-block:: cmake

add_subdirectory(lvgl)

This snippet sets up LVGL and tells it which lv_conf.h file to use:

.. code-block:: cmake

set(LV_BUILD_CONF_PATH path/to/my_lv_conf.h)
add_subdirectory(lvgl)

This snippet sets up LVGL and points to the folder where lv_conf.h is located:

.. code-block:: cmake

set(LV_BUILD_CONF_DIR path/to/directory)
add_subdirectory(lvgl)

This snippet adds LVGL and specifies to use Kconfig as the configuration system:

.. code-block:: cmake

set(LV_BUILD_USE_KCONFIG ON)
add_subdirectory(lvgl)

This snippet adds LVGL and specifies to use Kconfig as the configuration system and to use a specific defconfig:

.. code-block:: cmake

set(LV_BUILD_USE_KCONFIG ON)
set(LV_BUILD_DEFCONFIG_PATH path/to/my_defconfig)
add_subdirectory(lvgl)

To enable the demos and examples set these options:

.. code-block:: cmake

set(CONFIG_LV_BUILD_EXAMPLES ON)
set(CONFIG_LV_BUILD_DEMOS ON)
add_subdirectory(lvgl)

Below is a list of the available options/variables

.. list-table:: :header-rows: 1 :widths: 20 10 50

- Variable/Option
- Type
- Description
- LV_BUILD_CONF_PATH
- PATH
- Allows to set a custom path for lv_conf.h
- LV_BUILD_CONF_DIR
- PATH
- Allows to set a directory containing lv_conf.h
- LV_BUILD_USE_KCONFIG
- BOOLEAN
- When set KConfig is used as the configuration source. This option is disabled by default.
- LV_BUILD_DEFCONFIG_PATH
- PATH
- Specify to use a .defconfig file instead of the current .config in a Kconfig setup.
- LV_BUILD_LVGL_H_SYSTEM_INCLUDE
- BOOLEAN
- Enable if LVGL will be installed to the system or your build system uses a sysroot. Turning this option on implies that the resources generated by the image generation script will include lvgl.h as a system include. i.e: #include <lvgl.h>. This option is disabled by default.
- LV_BUILD_LVGL_H_SIMPLE_INCLUDE
- BOOLEAN
- When enabled the resources will include lvgl.h as a simple include, this option is enabled by default.
- LV_BUILD_SET_CONFIG_OPTS
- BOOLEAN
- When enabled, this option runs a script that processes the lv_conf.h/Kconfig configuration using pcpp to generate corresponding CONFIG_LV_* and CONFIG_LV_BUILD_* CMake variables based on the contents of lv_conf_internal.h. This requires python3 with venv and pip or access to a working pcpp. If KConfig is used, this is enabled automatically.
- CONFIG_LV_BUILD_DEMOS
- BOOLEAN
- When enabled builds the demos
- CONFIG_LV_BUILD_EXAMPLES
- BOOLEAN
- When enabled builds the examples
- CONFIG_LV_USE_THORVG_INTERNAL
- BOOLEAN
- When enabled the in-tree LVGL version of ThorVG is compiled
- CONFIG_LV_USE_PRIVATE_API
- BOOLEAN
- When enabled the private headers *_private.h are installed on the system

.. note::

When LV_BUILD_SET_CONFIG_OPTS or LV_BUILD_USE_KCONFIG are enabled, the options/variables beginning with the prefix CONFIG_* are automatically set to the values found in lv_conf.h