Cassowary incremental linear constraint solving for user interfaces

Document status: reviewed. Canonical source.

Summary

Cassowary is an incremental dual-simplex constraint solver designed for UI equalities, inequalities and preferences. It supports relationships that are awkward to express as a single parent-owned flow algorithm.

NUIF relevance

Constraint layout belongs as a distinct authored layout family rather than being forced into flex/grid. The core schema should model constraint identities, strengths and variables independently of one solver implementation.