ESP3D/libraries/lvgl-8.2.0/docs/get-started/cmake.md

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CMake

LVGL supports integrating with CMake. It comes with preconfigured targets for:

• Espressif (ESP32)
• MicroPython
• Zephyr

On top of the preconfigured targets you can also use "plain" CMake to integrate LVGL into any custom C/C++ project.

Prerequisites

• CMake ( >= 3.12.4 )
• Compatible build tool e.g.
  • Make
  • Ninja

Building LVGL with CMake

There are many ways to include external CMake projects into your own. A modern one also used in this example is the CMake FetchContent module. This module conveniently allows us to download dependencies directly at configure time from e.g. GitHub. Here is an example how we might include LVGL into our own project.

cmake_minimum_required(VERSION 3.14)
include(FetchContent)

project(MyProject LANGUAGES C CXX)

# Build an executable called "MyFirmware"
add_executable(MyFirmware src/main.c)

# Specify path to own LVGL config header
set(LV_CONF_PATH
    ${CMAKE_CURRENT_SOURCE_DIR}/src/lv_conf.h
    CACHE STRING "" FORCE)

# Fetch LVGL from GitHub
FetchContent_Declare(lvgl URL https://github.com/lvgl/lvgl.git)
FetchContent_MakeAvailable(lvgl)

# The target "MyFirmware" depends on LVGL
target_link_libraries(MyFirmware PRIVATE lvgl::lvgl)

This configuration declares a dependency between the two targets MyFirmware and lvgl. Upon building the target MyFirmware this dependency will be resolved and lvgl will be built and linked with it. Since LVGL requires a config header called lv_conf.h to be includable by its sources we also set the option LV_CONF_PATH to point to our own copy of it.

Additional CMake options

Besides LV_CONF_PATH there are two additional CMake options to specify include paths.

LV_LVGL_H_INCLUDE_SIMPLE which specifies whether to #include "lvgl.h" absolut or relative

ON (default)	OFF
"lvgl.h"	"../../lvgl.h"

LV_CONF_INCLUDE_SIMPLE which specifies whether to #include "lv_conf.h" and "lv_drv_conf.h" absolut or relative

ON (default)	OFF
"lv_conf.h"	"../../lv_conf.h"
"lv_drv_conf.h"	"../../lv_drv_conf.h"

I do not recommend disabling those options unless your folder layout makes it absolutely necessary.

Building LVGL examples with CMake

LVGL examples have their own CMake target. If you want to build the examples simply add them to your dependencies.

# The target "MyFirmware" depends on LVGL and examples
target_link_libraries(MyFirmware PRIVATE lvgl::lvgl lvgl::examples)

Building LVGL drivers and demos with CMake

Exactly the same goes for the drivers and the demos.

# Specify path to own LVGL demos config header
set(LV_DEMO_CONF_PATH
    ${CMAKE_CURRENT_SOURCE_DIR}/src/lv_demo_conf.h
    CACHE STRING "" FORCE)

FetchContent_Declare(lv_drivers
                     GIT_REPOSITORY https://github.com/lvgl/lv_drivers)
FetchContent_MakeAvailable(lv_drivers)
FetchContent_Declare(lv_demos
                     GIT_REPOSITORY https://github.com/lvgl/lv_demos.git)
FetchContent_MakeAvailable(lv_demos)

# The target "MyFirmware" depends on LVGL, drivers and demos
target_link_libraries(MyFirmware PRIVATE lvgl::lvgl lvgl::drivers lvgl::examples)

Just like the lv_conf.h header demos comes with its own config header called lv_demo_conf.h. Analogous to LV_CONF_PATH its path can be set by using the option LV_DEMO_CONF_PATH.