LittlevGL - Open-source Embedded GUI Library in Rust

![Original LittlevGL demo image](lv_demo.png)

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

--- ![Rust bindings usage demo code.](demo.png) ## 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: ```shell script $ 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](https://github.com/rust-lang/cargo/issues/7915). ```shell $ 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`](https://doc.rust-lang.org/beta/alloc/boxed/struct.Box.html)). That is required, so we can safely provide Rust pointers through FFI. For that reason, we do require [`alloc`](https://doc.rust-lang.org/alloc/) module to be available. ## Running the demo [This project contains examples that can run in a desktop simulator.](./examples) First, make sure to pull `lvgl-rs` submodules: ```shell $ 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](./lvgl/build.rs). ```bash $ DEP_LV_CONFIG_PATH=`pwd`/examples/include cargo build --package lvgl-codegen ``` Then run the `demo` example: ```shell $ 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. - [x] Displays: We use [`embedded_graphics`](https://docs.rs/embedded-graphics/0.6.2/embedded_graphics/) library to draw to the display. You can use `lvgl-rs` with any of the [`embedded_graphics` supported displays](https://docs.rs/embedded-graphics/0.6.2/embedded_graphics/#supported-displays). - [x] Events: You can listen and trigger events in widget objects. - [x] 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.