[Caption: Not all rectangles are created equal. In the ocean of pixels, Rectangle imparts rigorous geometric meaning to disordered windows.]
(0. Breaking the Topic: Entropy and Order)
New York is currently 2.51°C (36.5°F), under overcast skies. This grayscale tone always reminds me of the layered, chaotic windows on a screen—the “heat death” of the digital world.
When we talk about window management, what are we really talking about? Is it merely the self-cultivation of OCD? No. For developers, screen space is a direct mapping of brain capacity. A cluttered desktop is, in essence, a DDoS attack on your attention.
For a long time, the window management logic of macOS was filled with “artist’s arrogance”—it wanted you to drag freely and enjoy the fluid sensation. But in high-pressure coding scenarios, this “freedom” becomes a burden. While Windows solved this back in the Win 7 era with Aero Snap, macOS remained stagnant for years.
Until Spectacle stopped maintenance, Magnet started charging, and Rectangle emerged. It is not just a tool; it is an open-source movement against the entropy increase of the macOS UI. Even after Apple finally introduced native window snapping in macOS Sequoia (15.0), Rectangle remains unshaken.
Why? Because the native function is merely “usable,” while Rectangle represents the “limit.”
(1. The Core: Swift’s Geometric Scalpel)
Architectural Perspective: The Magic of AXUIElement
Rectangle’s core is not some arcane black magic, but an extreme tuning of macOS’s ancient yet powerful Accessibility API.
From a source code perspective, Rectangle’s operation mechanism can be broken down into three steps: Listen, Calculate, Inject.
- The Listener:
It utilizes theMASShortcutlibrary (a legacy of Spectacle, now modernized with Swift wrappers) to capture global keyboard events. Unlike ordinaryNSEvent, these shortcuts must be intercepted at the system level, even when the app is in the background. - The Calculation:
When the user pressesCtrl+Opt+Enter(Maximize), Rectangle doesn’t manipulate the window immediately. First, it accessesNSScreento obtain the current screen’s valid pixel dimensions (Visible Frame), filtering out the interference of the Dock and the Menu Bar.
This is why native split-screen sometimes obscures the Dock, while Rectangle is always precise. -
The Injection:
This is the most brilliant part. Rectangle uses theAXUIElementinterface, originally a backdoor designed by Apple for vision-assistive software.
swift
// Pseudo-code logic illustration
let element = AXUIElementCreateApplication(pid)
AXUIElementSetAttributeValue(element, kAXPositionAttribute, newPoint)
AXUIElementSetAttributeValue(element, kAXSizeAttribute, newSize)
It bypasses the superficial animations of the WindowServer, directly modifying thePositionandSizeattributes of the window object. This “surgical” operation guarantees millisecond-level response speed.
Design Philosophy: Stateless and Lightweight
Unlike Electron apps that easily consume hundreds of megabytes of memory, Rectangle is written in pure native Swift. It is almost “stateless”—it doesn’t save your window history (unless you use Todo mode); it only wakes up the moment it is triggered, performs the geometric calculation, and then quickly goes back to sleep.
This “Fire and Forget” design philosophy keeps its background CPU usage near zero. On development machines where resources are precious, this is the mark of a top-tier tool.
(2. The Clash: Trade-offs and Moats)
Technical selection is always the art of trade-offs. In 2026, by comparing the following three dimensions, we can clearly see where Rectangle stands.
1. Rectangle vs. Magnet (Paid Closed Source)
- Magnet is a model of commercial software: stable, but closed.
- Rectangle‘s advantage lies in transparency. As accessibility software, it requires high system privileges (controlling your computer). Would you rather hand the keys to a black box, or to an open-source project with 2.8k+ Stars on GitHub and fully audited code?
- Key Difference: Rectangle supports URL Schemes (
rectangle://execute-action?name=left-half). This means you can integrate it into Raycast, Alfred, or even Shell scripts to achieve complex automated workflows. This is something Magnet cannot do.
2. Rectangle vs. macOS Sequoia (Native)
Apple finally “Sherlocked” window snapping features in macOS 15.
- Native Features: Only support basic halves and quarters. It caters to 80% of average users.
- Rectangle: Supports thirds (1/3, 2/3), sixths, almost-maximize (leaving margins), and multi-monitor throwing.
- Conclusion: Native functions are the “floor”; Rectangle is the “ceiling.” If you are an Ultrawide user, the native split-screen is a waste of potential; only Rectangle’s “center third” layout truly utilizes the screen’s value.
3. Rectangle vs. Yabai / Amethyst (Tiling)
- Yabai is the radical faction. It forcibly takes over all windows, automatically tiling them. This requires users to completely reshape their habits and often requires disabling SIP (System Integrity Protection), which is high risk.
- Rectangle is the reformist faction. It retains the intuition of floating windows, intervening only when you need it. It doesn’t try to teach you how you “should” use a computer, but assists you in how you “want” to use it.
(3. Vision: The Essence of Tools and Antifragility)
From Spectacle to Rectangle, we see a relay of the open-source spirit.
In software engineering, as long as an API exists, a better wheel will appear. Rectangle’s victory proves the vitality of the “Unix Philosophy” in the GUI era: Do one thing and do it well.
Trend Projection: The Last Mile of Automation
Future window management won’t stop at “shortcuts.” Rectangle’s support for URL Schemes has already hinted at the direction—a programmable window environment.
Imagine this: when you open your IDE, a script triggers Rectangle to place the IDE in the left 2/3, the browser in the right 1/3, and automatically “Ignores” your Spotify window.
This isn’t sci-fi; this is a reality Rectangle can already achieve in conjunction with Shortcuts.
Blind Spot: The Overlooked “Muscle Memory”
We often ignore the impact of tools on neuroplasticity. After using Rectangle for three years, your fingers will automatically press Ctrl+Opt+→ before your brain even consciously issues the command. This zero-latency brain-computer interface experience is the core value that AI cannot easily replace.
(4. Conclusion: Geometry Under the Stars)
On this gloomy Saturday in New York, I can’t help but think of the structure of the constellation Lyra—a few stars constructing the shape of a harp in deep space with precise geometric relationships.
The world of code is the same. Entropy increase is the norm of the universe, and Rectangle is a geometric lighthouse we artificially build on a chaotic digital desktop. It is free, open-source, and perhaps a bit plain, but it defends our absolute control over pixels.
A bit of advice for developers:
Don’t just treat Rectangle as a split-screen tool. Go study its URL Schemes, go customize those niche “sixth-screen” shortcuts. In an era where algorithms try to take over everything, retaining a bit of precise manual control is a rare romance.
May your windows always align, and may your logic always close the loop.
References
- GitHub Project: rxhanson/Rectangle – Core source code and documentation
- Apple Developer: Accessibility API – Technical principle reference
- Hacker News: Rectangle vs Magnet discussion – Community review reference
—— Lyra Celest @ Turbulence τ
