# Velato
**An integration to parse and render [Lottie](https://airbnb.io/lottie) with [Vello](https://vello.dev).**
[](https://xi.zulipchat.com/#narrow/stream/197075-gpu)
[](https://deps.rs/repo/github/linebender/velato)
[](#license)
[](https://crates.io/crates/vello)\
[](https://crates.io/crates/velato)
[](https://docs.rs/velato)
[](https://github.com/linebender/velato/actions)
> [!WARNING]
> The goal of this crate is to provide coverage of the large Lottie spec, up to what vello can render, for use in interactive graphics. We are working towards correctness, but there are missing features listed below.
## Missing features
Several Lottie features are not yet supported, including:
- Non-linear easings
- Position keyframe (`ti`, `to`) easing
- Time remapping (`tm`)
- Text
- Image embedding
- Advanced shapes (stroke dash, zig-zag, etc.)
- Advanced effects (motion blur, drop shadows, etc.)
- Correct color stop handling
- Split rotations
- Split positions
## Usage
Velato makes it simple to encode Lottie as a [`vello::Scene`](https://docs.rs/vello/*/vello/struct.Scene.html).
```rust
// Parse your lottie file
let lottie = include_str!("../lottie.json");
let composition = velato::Composition::from_str(lottie).expect("valid file");
// Render to a scene
let mut new_scene = vello::Scene::new();
// Render to a scene!
let mut renderer = velato::Renderer::new();
let frame = 0.0; // Arbitrary number chosen. Ensure it's a valid frame!
let transform = vello::kurbo::Affine::IDENTITY;
let alpha = 1.0;
renderer.render(&composition, frame, transform, alpha, &mut new_scene);
```
## Examples
### Cross platform (Winit)
```shell
cargo run -p with_winit
```
You can also load an entire folder or individual files.
```shell
cargo run -p with_winit -- examples/assets
```
### Web platform
Because Vello relies heavily on compute shaders, we rely on the emerging WebGPU standard to run on the web.
Until browser support becomes widespread, it will probably be necessary to use development browser versions (e.g. Chrome Canary) and explicitly enable WebGPU.
This uses [`cargo-run-wasm`](https://github.com/rukai/cargo-run-wasm) to build the example for web, and host a local server for it
```shell
# Make sure the Rust toolchain supports the wasm32 target
rustup target add wasm32-unknown-unknown
# The binary name must also be explicitly provided as it differs from the package name
cargo run_wasm -p with_winit --bin with_winit_bin
```
There is also a web demo [available here](https://linebender.github.io/velato) on supporting web browsers.
> [!WARNING]
> The web is not currently a primary target for Vello, and WebGPU implementations are incomplete, so you might run into issues running this example.
## Community
Discussion of Velato development happens in the [Linebender Zulip](https://xi.zulipchat.com/), specifically the [#gpu stream](https://xi.zulipchat.com/#narrow/stream/197075-gpu). All public content can be read without logging in.
Contributions are welcome by pull request. The [Rust code of conduct](https://www.rust-lang.org/policies/code-of-conduct) applies.
## License
Licensed under either of
- Apache License, Version 2.0
([LICENSE-APACHE](LICENSE-APACHE) or )
- MIT license
([LICENSE-MIT](LICENSE-MIT) or )
at your option.
The files in subdirectories of the [`examples/assets`](/examples/assets) directory are licensed solely under
their respective licenses, available in the `LICENSE` file in their directories.
## Contribution
Unless you explicitly state otherwise, any contribution intentionally submitted
for inclusion in the work by you, as defined in the Apache-2.0 license, shall be
dual licensed as above, without any additional terms or conditions.