Fit for Windows

Snap Windows windows with the keyboard. Fit for Windows is the Windows counterpart of Fit for macOS.

The repository is named fit-windows; the installed application is simply Fit.

日本語版 README

Status

This repository contains the first working foundation. It currently provides:

• Win + Left/Right/Up/Down override while Fit is running
• half, two-thirds, and one-third size cycling
• quarter snapping by pressing perpendicular directions in sequence
• work-area-aware placement (taskbar excluded)
• multiple-monitor support for the active window
• a notification-area menu with pause, About, and Quit
• no third-party runtime or library dependencies

Settings UI, drag-to-edge previews, login startup, and signed releases are planned next.

Default shortcuts

Action	Shortcut
Left / right sizing cycle	Win + Left / Win + Right
Top / bottom sizing cycle	Win + Up / Win + Down
Quarter	Press horizontal and vertical directions in sequence

Each directional shortcut cycles through 1/2 → 2/3 → 1/3. For example, press Win + Left, then Win + Up, to move the focused window to the top-left quarter.

Fit intercepts only Win + Arrow. Other Windows shortcuts, including Win + Shift + Arrow, remain available. Pause the override from the notification-area menu to restore the standard Windows Snap behavior without quitting Fit.

Build

Requirements:

• Windows 10 version 2004 or later, or Windows 11
• .NET 8 SDK

git clone https://github.com/EitaroY/fit-windows.git
cd fit-windows
dotnet build Fit.sln --configuration Release

Run:

dotnet run --project src/Fit/Fit.csproj

Run the dependency-free core tests:

dotnet run --project tests/Fit.Core.Tests/Fit.Core.Tests.csproj

How it works

Fit uses public Windows APIs only:

• WH_KEYBOARD_LL to intercept the four Windows Snap shortcuts
• GetForegroundWindow to select the active window
• MonitorFromWindow and GetMonitorInfo to obtain the usable screen area
• SetWindowPos to move and resize the window

The keyboard hook performs no window work itself; it immediately queues the action onto the application dispatcher. Closing Fit removes the hook and leaves Windows settings unchanged.

Windows prevents a normal process from controlling some elevated applications. Fit intentionally does not request administrator privileges by default.

Distribution model

The intended model matches Fit for macOS:

• developers may clone and build the GPL source themselves
• signed binaries may be published on GitHub Releases
• an official packaged build may be sold through Microsoft Store

Microsoft Store packaging and commerce do not change the name shown by the installed application: it remains Fit. The Store listing may need a longer unique product name if Fit is unavailable for reservation.

Project structure

src/Fit.Core/          Platform-independent layout calculations
src/Fit/               WPF application and Win32 integration
tests/Fit.Core.Tests/  Dependency-free executable test suite
docs/DESIGN.md         Architecture and implementation decisions

License

GPL-3.0-only. See LICENSE.

Copyright © 2026 Eitaro Y.