kozan-platform — Abstract platform layer for Kozan.

Like Chrome's content/ — defines the contract between the engine and the windowing system. Zero windowing-backend dependency.

The windowing backend (e.g., kozan-winit) implements PlatformHost and drives the event loop. This crate provides:

Abstract types: WindowId, ViewId, WindowConfig
PlatformHost trait: view→main-thread communication
ViewEvent / LifecycleEvent: main→view-thread messages
ViewThreadHandle / ViewContext: per-view threading model
WindowManager<R>: the brain — routes events, owns pipelines
Renderer / RenderSurface traits: GPU backend abstraction

Architecture

kozan-winit (or any backend)
  ├── implements PlatformHost
  ├── creates OS windows
  ├── passes raw window handles to WindowManager
  └── converts OS events → WindowManager.on_*()

kozan-platform (this crate — THE BRAIN)
  ├── WindowManager<R: Renderer>: owns all windows + renderer
  ├── WindowPipeline: spawns view + render threads per window
  ├── RenderLoop: compositor + vsync loop
  ├── ViewContext: user-facing API inside view thread
  └── Renderer / RenderSurface traits

kozan-vello (or any GPU backend)
  ├── implements Renderer + RenderSurface
  └── zero winit knowledge

kozan-core (engine)
  ├── input/ types (InputEvent, Modifiers, etc.)
  ├── widget/ (FrameWidget, Viewport — future)
  └── dom/, events/, style/

kozan-platform 0.1.0

Architecture