Skip to main content

lui

GPU-accelerated HTML/CSS renderer for Rust, built on wgpu.

lui is a complete HTML/CSS rendering engine that runs directly on the GPU via wgpu (Vulkan, Metal, DX12). It parses real HTML5, applies CSS styling (Flexbox + Grid), lays out page geometry, and renders through custom GPU pipelines — all from a single Rust binary. No web browser. No JavaScript. Ever.

Key Features​

  • GPU rendering via wgpu — Quad SDF pipeline, glyph atlas, and image pipeline all run on Vulkan/Metal/DX12
  • CSS Flexbox & Grid — Complete CSS Flexbox Level 1 and CSS Grid with fr units, minmax(), repeat(), and auto-placement
  • Full text shaping — cosmic-text (HarfBuzz-based) shaping with glyph atlas, text-align, letter-spacing, text-transform, and text decorations
  • Form controls — <input> (22 types), <textarea>, <button> with full text editing, caret, selection, and clipboard
  • No JavaScript needed — All logic is Rust. Callbacks are Rust closures. No <script> execution, ever.

Architecture Pipeline​

HTML/CSS string
   │
   ▼  lui-parser           Tokenizer + tree builder + CSS parser
Tree<Node<Element>>
   │
   ▼  lui-style            UA defaults + selector match + cascade + inheritance
CascadedTree<CascadedNode>
   │
   ▼  lui-layout-old           Block flow + Flex + Grid + Inline (IFC) + text shaping
LayoutBox tree
   │
   ▼  lui (paint.rs)       LayoutBox → DisplayList (quads + glyphs + clip ranges)
DisplayList
   │
   ▼  lui-renderer         Quad pipeline (SDF) + Glyph pipeline + scissor/clip
Frame on wgpu surface

First Steps​

New to lui? Start with the Getting Started overview to understand what lui is, then follow the Quick Start guide to get your first window on screen.