Window Management System
Windowing only works when the rules live above the apps — coordination by contract, not shared state.
Context
When Amazon built its own in-vehicle OS, multiple apps and system surfaces had to coexist — stacked, side-by-side, overlaid — staying predictable and performant. The hard part: processes were isolated and couldn't see each other. And in a moving vehicle, an unpredictable window isn't a polish issue — it's a safety one.
My role
Lead designer for the window-management model: layout, focus, z-order, and the cross-process contracts. Partnered closely with platform and application engineering, since the system only held if their isolated apps honored the same rules.
Approach
A governed windowing framework high in the OS, coordinating apps that had no visibility into each other through directional signals and contracts rather than shared state — plus z-order and priority rules, glassmorphic depth treatments, and a responsive grid for running apps concurrently across screen configurations.
The hard call
Contracts and signals over shared state. It's more coordination upfront, but shared state would have traded away the encapsulation and performance guarantees the platform depended on. In a safety context, stability wins over convenience.
Outcome
Predictable multi-window behavior at the OS level, advanced visual depth without destabilizing performance, and concurrent apps made viable for the digital cabin. Track record: the windowing system I designed earlier at Roku — Shoji — still ships across millions of devices a decade later. I build this layer to last.