LittlevGL - Open-source Embedded GUI Library in Rust

LittlevGL 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.

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

Official LittlevGL Website · C library repository · Live demo

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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 LittlevGL library.

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

Requirements / Limitations

LittlevGL C libary do allocate memory dynamically and we need to allocate memory on the heap in the Rust side as well (Box). That is required, so we can safely provide Rust pointers through FFI. For that reason, we do require alloc module to be available.

Running the demo

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 

Some parts of lvgl-rs are auto-generated. The package lvgl-codegen is responsible for the generated code. When building from source, we need to first compile the lvgl-codegen tool. The lvgl-codegen tool is used automatically in the lvgl package build.

$ DEP_LV_CONFIG_PATH=`pwd`/examples/include cargo build --package lvgl-codegen

Then run the demo example:

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

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. You can use lvgl-rs with any of the embedded_graphics supported displays.
• 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
• Fonts
• 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.