#low-memory #user-interface #embedded-devices #api-bindings #memory-allocator #littlevgl #graphical-interfaces

no-std lvgl

LVGL bindings for Rust. A powerful and easy-to-use embedded GUI with many widgets, advanced visual effects (opacity, antialiasing, animations) and low memory requirements (16K RAM, 64K Flash).

13 releases

0.6.2 Apr 2, 2023
0.6.1 Apr 2, 2023
0.5.2 Mar 6, 2021
0.4.0 Jun 19, 2020
0.1.1 Apr 12, 2020

#84 in GUI

24 downloads per month
Used in 2 crates

MIT license

11MB
217K SLoC

C 214K SLoC // 0.1% comments Rust 2.5K SLoC // 0.1% comments Shell 147 SLoC // 0.3% comments Scons 66 SLoC

LVGL - Open-source Embedded GUI Library in Rust

Original LVGL demo image

LVGL provides everything you need to create a Graphical User Interface (GUI) on embedded systems with easy-to-use graphical elements, beautiful visual effects and low memory footprint.

LVGL is compatible with #![no_std] environments by default.

Rust to WASM demo · Official LVGL Website · C library repository · Official live demos


Rust bindings usage demo code.

System Build Dependencies

In order to build the lvgl project you will need the following system dependencies to be installed:

$ sudo apt install build-essential llvm clang

If you want to build the examples, then you will need to install SDL2 as well.

$ sudo apt install libsdl2-dev

Usage

Edit your Cargo.toml file dependencies with:

$ cargo add lvgl

The build requires the environment variable bellow to be set:

  • DEP_LV_CONFIG_PATH: Path to the directory containing the lv_conf.h header file used for configuration of LVGL library.
  • (Optional) LVGL_FONTS_DIR: Directory for custom fonts generated for use in LVGL. See the documentation for usage.
  • (Optional) LVGL_INCLUDE: C headers to include during the build if using the drivers feature, comma-separated. The default is /usr/include,/usr/local/include.
  • (Optional) LVGL_LINK: C libraries to link in during the build if using the drivers feature, comma-separated. The default is SDL2.

We recommend the lv_conf.h file to be in your project's root directory. If so, the command to build your project would be:

$ DEP_LV_CONFIG_PATH=`pwd` cargo build

Building for embedded environments

We make use of bindgen for generating the bindings to LittlevGL at build time. There is a problem in cargo when building for no_std, so we need to use a workaround to build "lvgl-rs". The mainstrem issue in cargo is being tracked at rust-lang/cargo#7915.

$ DEP_LV_CONFIG_PATH=`pwd` cargo build -Zfeatures=build_dep

The unsafe_no_autoinit feature must also be enabled when building for baremetal targets. See its documentation in Cargo.toml for notes on usage.

LVGL Global Allocator

A global allocator for Rust leveraging the LVGL memory allocator is provided, but not enabled by default. Can be enabled by the feature lvgl_alloc. This will make all dynamic memory to be allocated by LVGL internal memory manager.

Running the demo

Hint for macOS users: Before you run the demos you need to make sure you have libsdl installed on your machine. To install it, use HomeBrew:

$ brew install sdl2

This project contains examples that can run in a desktop simulator.

First, make sure to pull lvgl-rs submodules:

$ git submodule init
$ git submodule update 

Then run the demo example:

$ DEP_LV_CONFIG_PATH=`pwd`/examples/include cargo run --example demo --features="alloc"

Feature Support

The bindings are still in development. There are many features of LVGL that needs to be exposed by lvgl-rs. In this section you can check what is implemented at the moment.

Features

List of LVGL features that impacts the library usage in general.

  • Displays: We use embedded_graphics library to draw to the display, along with lv_drivers. You can use lvgl-rs with any of the embedded_graphics supported displays, and those supported by lv_drivers. Note: lv_drivers support is currently experimental.
  • Events: You can listen and trigger events in widget objects.
  • Styles: You can set styles in any exposed object. We are still missing the possibility of defining global base styles.
  • Input Devices: Input devices supported by lv_drivers can be used, and custom handlers can be specified for embedded_graphics. Currently, only pointer input devices are supported. Note: lv_drivers support is currently experimental.
  • Fonts: All fonts built-in to LVGL can be used on nightly Rust if the nightly feature is enabled. Custom fonts can also be encoded into a C file (see the documentation on the font module).
  • Images
  • File system
  • Animations
  • Tasks

Widgets

Widgets currently implemented might have some missing features. If the widget you want to use is not exposed or is missing a feature you want to make use, please send a Pull Request or open an issue.

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Dependencies

~0.6–4MB
~68K SLoC