LVGL on top of Linux graphics stack

Example project to use LVGL on top of Linux graphics stack. Currently supported backends are legacy framebuffer (fbdev), modern DRM/KMS, Wayland or SDL2.

By default, legacy framebuffer backend uses /dev/fb0 device node, DRM/KMS backend uses '/dev/dri/card0' card node, SDL2 uses window resolution of 800x480.

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

Build dependencies

Check the Dockerfiles for the build dependencies.

Clone the project

Clone the LVGL Framebuffer Demo project and its related sub modules.

git clone https://github.com/lvgl/lv_port_linux.git
cd lv_port_linux/
git submodule update --init --recursive

Select graphics backend

To use legacy framebuffer (fbdev) support, adjust lv_conf.h as follows:

#define LV_USE_LINUX_FBDEV	1
#define LV_USE_LINUX_DRM	0
#define LV_USE_SDL		0
#define LV_USE_WAYLAND		0

To use modern DRM/KMS support, adjust lv_conf.h as follows:

#define LV_USE_LINUX_FBDEV	0
#define LV_USE_LINUX_DRM	1
#define LV_USE_SDL		0
#define LV_USE_WAYLAND		0

To use SDL2 support, adjust lv_conf.h as follows:

#define LV_USE_LINUX_FBDEV	0
#define LV_USE_LINUX_DRM	0
#define LV_USE_SDL		1
#define LV_USE_WAYLAND		0

To use wayland, adjust lv_conf.h as follows:

#define LV_USE_LINUX_FBDEV	0
#define LV_USE_LINUX_DRM	0
#define LV_USE_SDL		0
#define LV_USE_WAYLAND		1

cmake

cmake -B build -S .
make -C build -j

Makefile

make -j

Command line options

Command line options are used to modify behavior of the demo, they take precedence over environment variables.

Wayland

• -f - enters fullscreen on startup
• -m - maximizes window on startup
• -w <window width> - set the width of the window
• -h <window height> - set the height of the window

SDL2

• -w <window width> - set the width of the window
• -h <window height> - set the height of the window

Environment variables

Environment variables can be set to modify the behavior of the demo.

Legacy framebuffer (fbdev)

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

EVDEV touchscreen/mouse pointer device

• LV_LINUX_EVDEV_POINTER_DEVICE - override default (/dev/input/by-id/my-mouse-or-touchscreen) input device

DRM/KMS

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

SDL2

• LV_SIM_WINDOW_WIDTH - width of SDL2 surface (default 800).
• LV_SIM_WINDOW_HEIGHT - height of SDL2 surface (default 480).

Wayland

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

Run the demo application

FBDEV

Unpriviledged users don't have access to the framebuffer device /dev/fb0 sudo or su must be used.

cmake:

sudo ./bin/lvglsim

Makefile:

cd build/bin/
sudo main

Access to the framebuffer device can be granted by adding the unpriviledged user to the video group

cmake:

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