LVGL on top of Linux graphics stack

This is an example project demonstrating how to use LVGL on a GNU/Linux systems and other Unix-like operating systems

LVGL provides drivers for many graphics backends. Legacy framebuffer (fbdev), modern DRM/KMS, Wayland, X11, GLFW3 and SDL2.

Check out this blog post for a step by step tutorial for fbdev https://blog.lvgl.io/2018-01-03/linux_fb

Clone the project

Clone the project

git clone https://github.com/lvgl/lv_port_linux.git
cd lv_port_linux/

LVGL is a submodule of lv_port_linux, use the following command to fetch it, it will be downloaded to the lvgl/ directory

git submodule update --init --recursive

Configure drivers and libraries

Adjust lv_conf.defaults to select the drivers and libraries that will be compiled by modifying the following definitions, setting them to 1 or 0

You can also start with a default config based on the drivers you want to use, you can find a default config for each graphic driver inside the configs folder.

You can either replace lv_conf.defaults manually or using CMake

cmake -B build -DCONFIG=<config_name> 

With <config_name> the name of the config without the .defaults extension, eg: configs/wayland.defaults becomes wayland.

Graphics drivers

Definition	Description
LV_USE_LINUX_FBDEV	Legacy frame buffer (/dev/fb*)
LV_USE_LINUX_DRM	DRM/KMS (/dev/dri/*)
LV_USE_SDL	SDL
LV_USE_WAYLAND	WAYLAND
LV_USE_X11	X11
LV_USE_GLFW	GLFW3

Device drivers

Definition	Description
LV_USE_EVDEV	libevdev input devices
LV_USE_LIBINPUT	libinput input devices

Install dependencies

Install the required dependencies for the selected drivers by checking the documentation for each driver here

You can also check the Dockerfiles to get the names of the packages for various distributions

Build instructions

LVGL supports GNU make and CMake

CMake

cmake -B build
cmake --build build -j$(nproc)

Cross compilation is supported with CMake, edit the user_cross_compile_setup.cmake to set the location of the compiler toolchain and build using the commands below

cmake -B build -DCMAKE_TOOLCHAIN_FILE=./user_cross_compile_setup.cmake 
cmake --build build -j$(nproc)

Installing LVGL

It is possible to install LVGL to your system using cmake:

cmake --install ./build

Run the demo application

./build/bin/lvglsim

This will start the widgets demo

If multiple backends are enabled you can run with a specific backend via the -b option

./build/bin/lvglsim -b sdl

To get a list of supported backends use the -B option

Environment variables

Environment variables can be set to modify the behavior of the driver(s) Check the documentation of the drivers for more details

Legacy framebuffer (fbdev)

• LV_LINUX_FBDEV_DEVICE - override default (/dev/fb0) framebuffer device node.

EVDEV touchscreen/mouse pointer device

• LV_LINUX_EVDEV_POINTER_DEVICE - the path of the input device, i.e. /dev/input/by-id/my-mouse-or-touchscreen. If not set, devices will be discovered and added automatically.

DRM/KMS

• LV_LINUX_DRM_CARD - override default (/dev/dri/card0) card.

Simulator

• LV_SIM_WINDOW_WIDTH - width of the window (default 800).
• LV_SIM_WINDOW_HEIGHT - height of the window (default 480).

Permissions

By default, unpriviledged users don't have access to the framebuffer device /dev/fb0. In such cases, you can either run the application with sudo privileges or you can grant access to the video group.

sudo adduser $USER video
newgrp video
./build/bin/lvglsim