Pax

Pax is a user interface language and rendering engine. Use Pax to build GUIs and interactive 2D graphics with Rust.

Pax compiles through Rust into native Mac apps (LLVM) or Web apps (WebAssembly). Support for more platforms is planned, at least: Linux, Windows, iOS, and Android.

As of September 2022, Pax is being developed in the open, in alpha preview.

Example

Writing Pax is intended to feel familiar, and the language borrows many ideas from prior art.

Following is a simple Pax component called IncrementMe:

//increment-me.rs

use pax::*;
use pax_std::{Text};
use pax_std::forms::{Button, ArgsButtonSubmit};
use pax_std::layout::{Stacker};

/// Following is the description of a simple form GUI, encapsulated 
/// into a reusable component called `IncrementMe`.

#[pax(
  <Stacker cells=2>
    <Text>{"I have been clicked " + self.num_clicks + " times."}</Text>
    <Button @submit=self.increment>"Increment me!"</Button>
  </Stacker>
)] 
pub struct IncrementMe {
  pub num_clicks: Property<i64>
}
impl IncrementMe {
  pub async fn increment(&self, args: ArgsButtonSubmit) {
    let old_num_clicks = self.num_clicks.get();
    self.num_clicks.set(old_num_clicks + 1);
  }
}

Any Pax component like the example above may be included inside other Pax components, or may be mounted as the root of a stand-alone app.

See a more thorough and a running example.

Features

Fast — native rendering targeting 120FPS animations
Accessible — supports native screen readers for text & GUI elements
Lightweight — targeting <100kB baseline for WebAssembly binary
Declarative UI language makes it easy to reason about complex scenes and GUIs
Reusable component system includes an optional standard library of GUI components
Multi-platform — currently supports building Web apps or native macOS apps

Docs

Getting Started

Refer to the guide for getting started in the Pax docs.

Current status & support

Pax is in alpha-preview and is not yet viable for building apps — read the latest status.

Support matrix:

	Web browsers	Native iOS	Native Android	Native macOS	Native Windows	Native Linux
Development harness & chassis	✅	⏲	⏲	✅	⏲	⏲
2D rendering and UIs	✅ Canvas	⏲ CoreGraphics	⏲ Cairo	✅ CoreGraphics	⏲ Direct2D	⏲ Cairo
3D rendering and UIs	⏲	⏲	⏲	⏲	⏲	⏲
Vector graphics APIs	✅	⏲	⏲	✅	⏲	⏲
2D layouts	✅	⏲	⏲	✅	⏲	⏲
Animation APIs	✅	⏲	⏲	✅	⏲	⏲
Native text rendering	✅ DOM	⏲ UIKit	⏲ android:*	✅ SwiftUI	⏲ System.Windows.Forms	⏲ GTK
Native form elements	⏲ DOM	⏲ UIKit	⏲ android:*	⏲ SwiftUI	⏲ System.Windows.Forms	⏲ GTK
Native event handling (e.g. Click, Tap)	✅	⏲	⏲	✅	⏲	⏲
Rust host language	✅ WASM	⏲ LLVM	⏲ LLVM	✅ LLVM	⏲ LLVM	⏲ LLVM
JS/TypeScript host language	⏲	⏲	⏲	⏲	⏲	⏲

Legend:
✅ Supported
⏲ Not yet supported

License

This project is licensed under either of:

at your option.

Development

Environment setup

Use rustc 1.65.0 via rustup

Optional environment setup, web chassis

Install wasm-opt via binaryen:
```
brew install binaryen
```

Install 'wasm-pack' via:

 curl https://rustwasm.github.io/wasm-pack/installer/init.sh -sSf | sh

Install node: https://nodejs.org/en/download/

Install yarn:

# if necessary: sudo chown -R yourusername /usr/local/lib/node_modules 
npm i --global yarn

Optional environment setup, macOS chassis

Install xcode, command line utils

Running Development Environment

First, refer to the latest project status

The current leading edge of development is in the compiler —

cd pax-compiler
./run-example.sh

To run pax-example's parser binary and print its output to stdout:

cd pax-example
cargo build --bin=parser --features=parser

To run a full, compiled Pax example you must check out an older branch and run the demo there.

git checkout jabberwocky-demo
./run.sh # or ./run-web.sh

To initialize the docs submodule, for super-grep powers:

git submodule update --init --recursive

As needed, review the git submodule docs.

Architectural Reference

Runtime dependency & codegen graph

Pax compiler sequence diagram | Compiler source

GRVYDEV/pax

Pax