Layer Hierarchy

Presentar's vertical architecture.

Layer Diagram

┌─────────────────────────────────────────────────────────────────┐
│  Layer 9: App Runtime                                           │
│  - YAML parser, .apr/.ald loaders, Pacha integration            │
├─────────────────────────────────────────────────────────────────┤
│  Layer 8: Presentar (Reactive UI Framework)                     │
│  - Widget tree, layout engine, event dispatch, state            │
├─────────────────────────────────────────────────────────────────┤
│  Layer 7: Trueno-Viz (GPU Rendering Primitives)                 │
│  - Paths, fills, strokes, text, charts, WGSL shaders            │
├─────────────────────────────────────────────────────────────────┤
│  Layer 6: Trueno (SIMD/GPU Compute)                             │
│  - Tensor ops, backend dispatch, memory management              │
└─────────────────────────────────────────────────────────────────┘

Layer 6: Trueno

Foundation layer

• SIMD-accelerated tensor operations
• Memory management
• Backend abstraction (CPU/GPU)

Layer 7: Trueno-Viz

Rendering primitives

• Paths, fills, strokes
• Text rendering
• WGSL shaders

Layer 8: Presentar

UI Framework

• Widget trait and tree
• Layout engine
• Event system
• State management

Layer 9: App Runtime

Application layer

• YAML manifest parsing
• Model loading (.apr)
• Dataset loading (.ald)
• Pacha registry integration

Dependencies Flow

App Runtime
    ↓ uses
Presentar
    ↓ uses
Trueno-Viz
    ↓ uses
Trueno

Verified Test

#[test]
fn test_layer_independence() {
    // Each layer can be tested independently
    use presentar_core::{Size, Constraints};

    // Core layer works without higher layers
    let c = Constraints::loose(Size::new(100.0, 100.0));
    assert_eq!(c.biggest(), Size::new(100.0, 100.0));
}