Arnimate: A 2D Animation Editor Built in Rust
TL;DR
I'm building Arnimate, a 2D vector animation editor in Rust. It's GPU-accelerated via wgpu, runs on desktop and web, and aims to fill the gap left by Adobe Animate's slow decline. The web version is free to use.
Try the live demo (Chrome/Edge only — requires WebGPU).
Why Build Another Animation Editor?
Adobe Animate is effectively in maintenance mode. Rive and Lottie tools are great for motion graphics, but they're not full animation editors — you can't do frame-by-frame character animation in them. There's a real gap in the market for a proper 2D animation tool that's modern and fast.
Arnimate is my attempt at filling that gap. It's a full-featured 2D vector animation editor with:
- Frame-by-frame animation with onion skinning
- 47 animatable properties — position, rotation, scale, opacity, colors, path morph, effects, and more
- GPU-accelerated rendering via wgpu with custom WGSL shaders
- Visual effects — Gaussian blur, glow, drop shadow, all rendered on the GPU
- Bezier path editing with a pen tool, pencil tool, and shape tools
- Lottie export for web/mobile deployment
- Audio support — import audio tracks and sync animation to sound
- Full undo/redo via a command pattern history system
Architecture
The stack is Rust all the way down:
- wgpu for GPU rendering — custom pipelines for fills (Loop-Blinn curve rendering), strokes, text, blur (separable Gaussian, multi-pass), and compositing
- egui for the UI — immediate-mode GUI that runs on desktop and compiles to WebAssembly
- Generational arena scene graph — stable node references that survive deletions, with parent/child relationships and per-node animation data
- Custom math library — 2D primitives ported from kurbo (bezier paths, affine transforms, hit testing, triangulation)
The rendering pipeline runs per frame: evaluate animation keyframes → traverse scene graph → tessellate paths → upload to GPU → render fill/stroke/text → apply effects (shadow → glow → blur) → composite layers → blit to screen.
Effects are particularly interesting — each one (blur, glow, shadow) is a separate GPU pipeline using egui_wgpu paint callbacks. The Gaussian blur is separable (horizontal then vertical pass) with multi-pass support for large radii, where sigma composes in quadrature: σ_per_pass = target_σ / √passes.
WebAssembly
The whole editor compiles to WebAssembly and runs in the browser via WebGPU. The wasm binary is about 7 MB — not small, but reasonable for a full animation editor with GPU shaders. It's the same codebase as the desktop version, with platform abstraction for file I/O and audio.
WebGPU support is still limited to Chrome and Edge, but it's the future of GPU on the web. Safari and Firefox support is coming.
What's Next
Arnimate is still in active development. The core animation engine and rendering pipeline are solid, but there's a lot of polish work ahead — better tool UX, more export formats, skeletal animation/rigging, and community features. The web version is and will remain free to use.