$ show rxhanson/Rectangle
Rectangle is a production macOS menu-bar window-management utility that moves, resizes, and tiles application windows through keyboard shortcuts and drag-to-snap. It is not a research or data project; it is a purely native desktop application. It reads and writes window geometry via the macOS Accessibility API (AXUIElement), supporting dozens of layout actions — halves, thirds, quarters, sixths, eighths, ninths, twelfths, sixteenths, maximize, center, cascade, display transfer, and multi-window grid/row/column tiling — plus stacked-window cycling, a todo-mode sidebar, cooperative corner resize, and an optional animation engine. Architecturally, this is a Swift/Cocoa menu-bar app (LSUIElement, no dock icon, no backend). AppDelegate wires together ShortcutManager (MASShortcut bindings), WindowManager (action orchestration), SnappingManager (drag-to-snap with placement preview), MultiWindowManager (tile/cascade/stack), and a SwiftUI Settings window backed by a typed Defaults system persisted in NSUserDefaults with JSON import/export. The heart of the layout logic is a strategy pattern: a WindowCalculation protocol with roughly a hundred small calculation classes, each implementing one placement, applied through a chain of WindowMover implementations (standard, fixed-size, best-effort, edge-alignment) and optionally a display-link-driven animation pipeline with pacing, settlement, and handoff verification. The primary data flow is user input (shortcut/menu/drag) → WindowAction enum → WindowCalculation produces a target rectangle from the current screen, window, and gap state → a WindowMover writes the frame through AXUIElement with edge correction, followed by optional animation and post-move verification. Screen detection, multi-display transfer, gap math, and stack detection are separated into focused utilities. External dependencies are limited to AppKit/QuartzCore, the undocumented macOS Accessibility API, a forked-and-pinned MASShortcut, and Sparkle for auto-updates. The codebase is professionally maintained with unit tests for geometry, grid tiling, stack detection, defaults serialization, and cooperative resize, plus GitHub Actions CI that produces signed DMGs. Its main weaknesses are scale-related: a monolithic calculation factory and a ~140-value WindowAction enum with duplicated metadata, a single ~96k-token test file, and near-duplicate calculation classes for fine-grained grids. The strongest reusable assets are generic utilities (TTL cache, debounce) and pure-geometry modules that are decoupled from app state.
The LLM identified 5 files worth highlighting for reuse:
A generic TTL cache with linked-list purge. Self-contained (Foundation only), it stores keyed values with expiration and evicts in insertion/expiry order, making it ideal for short-lived memoization such as throttling expensive AXUIElement queries. Drop-in reusable in any Swift project without modification; demonstrates clean generic design and predictable eviction semantics.
A generic debounce utility that coalesces high-frequency events (resize churn, settings changes) into a single trailing execution after a fixed delay. Fully self-contained and generic over the payload, so it can be extracted into any Swift or macOS codebase needing rate-limited dispatch.
A balanced band-based grid layout algorithm that distributes windows into rows and columns while honoring per-window size constraints (resizable vs. fixed) and OS-reported clamp feedback. It is pure layout logic with dedicated unit tests (GridTilingTests.swift) and can be reused in any project needing constraint-aware rectangle arrangement.
Pure geometry for detecting stacked/overlapping windows: cascade clustering, corner matching, and hover/cycle region computation. Decoupled from app state and covered by StackBadgeGeometryTests; the algorithms generalize to any spatial-UI or window-management project needing to group overlapping rectangles.
Computes predictable cascade/overlap offsets for stacked windows so activated or restored windows land at a deterministic stagger position. Pure geometry with unit-test coverage (OverlapOffsetGeometryTests); reusable in any tiling or stacking window manager for offsetting overlapping rectangles.