WormsCursor

A tiny Windows tray utility that rotates the mouse cursor to follow your movement direction — like the aiming arrow in Worms 3D. Move the mouse right and the arrow points right; sweep it down and it smoothly slews to point down. The link/hand cursor rotates the same way.

It runs in the background from the system tray, with no main window.

⚠️ It replaces the system-wide arrow cursor (SetSystemCursor) while running, so every app sees the rotated arrow. The defaults are restored on quit and on a crash, and WormsCursor reloads the real cursor scheme on every launch — so if it's ever killed outright (Task Manager "End Task", Visual Studio "Stop Debugging") and the cursor stays rotated, just starting it again clears it. To fix it without relaunching, run tools/RestoreCursor.ps1 (logging off resets it too).

Demo

video.mp4

The cursor rotating to follow your mouse movement.

Cursors

WormsCursor themes all 14 standard system cursors, each with its own physics-driven motion:

Generated by the WormsCursor.Preview tool: dotnet run --project src/WormsCursor.Preview -- assets/cursors.png (writes a dark sheet plus a transparent one).

How it works

• At startup the engine pre-renders 360 rotated copies of the arrow (one per degree) as cursors, each with the hotspot pinned to the arrow tip.
• A background loop polls the cursor position (144 Hz by default) and computes the movement direction from accumulated travel, so ±1 px jitter doesn't make the arrow wobble on straight or vertical moves.
• The displayed angle is animated toward the target direction (a fixed deg/s slew), so turns look smooth instead of snapping.
• Both the arrow (OCR_NORMAL) and the hand/link cursor (OCR_HAND) rotate. The hand is drawn the same way as the arrow — a filled silhouette plus a pen-stroked outline, finger separators and knuckle creases — so it shares the arrow's colour, size and outline thickness (the geometry is baked into HandShape.cs).
• The busy / progress cursors are themed too. App-starting (OCR_APPSTARTING) is the rotating arrow with a spinning ring of dots that hangs off its tail like a pendulum — swinging out as you move and settling when you stop — while wait (OCR_WAIT) is the same ring centred on the pointer (spin only). They animate only while actually on screen, so an idle tray costs nothing.
• The help cursor (OCR_HELP) hangs a "?" upside-down off the arrow's tail on the same string, swinging to the sides as you move and settling when you stop.
• The crosshair (OCR_CROSS) is a precision reticle — a centre dot, four ticks and a slowly-rotating broken ring; the ticks breathe and spread out (recoil) when you move fast, then settle.
• The text / I-beam cursor (OCR_IBEAM) is a flexible beam: the bottom stays rigid while the top sways opposite to your motion on a soft spring, wobbling like jelly and settling.
• The resize cursors (OCR_SIZEWE / SIZENS / SIZENWSE / SIZENESW) and the move cursor (OCR_SIZEALL) are stretched-taffy double-arrows — drag along an axis and the shaft necks thin while the heads fly apart on a spring, then blob back; move crosses a horizontal and a vertical taffy into a 4-way glyph.
• The unavailable cursor (OCR_NO) is a red circle-with-slash whose ring is a jelly blob: it deforms into an egg along the direction of travel and wobbles back to round.
• Alternate-select (OCR_UP) reuses the same rotating arrow.
• The animated cursors re-render only while actually on screen (matched via GetCursorInfo against the live system handle), so an idle tray uses no CPU.

Known issues

• Animated cursors flicker on a mixed-DPI multi-monitor setup. If your monitors run at different display scales (e.g. 125% on one, 150% on another), the animated cursors (busy/wait, app-starting, help, crosshair, …) can strobe while shown on the higher-DPI screen. They animate by re-installing the cursor via SetSystemCursor every frame, and on a monitor whose scale differs from the one the cursor was created for, Windows re-composites the global cursor on each swap — which flashes. The static cursors (the rotating arrow/hand at rest) are re-installed only on a direction change, so they don't flicker. Single-DPI setups and matching scales are unaffected. Workarounds: set both monitors to the same scale, or enable Pointer trails (Settings → Bluetooth & devices → Mouse → Additional mouse settings → Pointer Options, shortest setting), which forces a cursor-draw path that sidesteps the flicker. A proper fix would mean drawing the animated cursors in our own overlay instead of through SetSystemCursor (tracked for a future release).

Project structure

WormsCursor.sln
├─ src/
│  ├─ WormsCursor.Core/      Engine — no UI dependencies
│  │   ├─ CursorEngine.cs     P/Invoke, cursor building, tracking + animation loop
│  │   ├─ ArrowRenderer.cs    Draws the arrow (size, colours, thickness, corner radius)
│  │   ├─ HandRenderer.cs     Draws the hand/link cursor (solid fill + baked line art)
│  │   ├─ ProgressRenderer.cs Draws the composited cursors (busy, help, crosshair, text, resize/move, unavailable)
│  │   ├─ HandShape.cs        Baked hand geometry (silhouette + crease marks)
│  │   ├─ CursorSettings.cs   Tunable parameters (persisted as JSON)
│  │   └─ SettingsStore.cs    Load/save settings in %LocalAppData%\WormsCursor\
│  ├─ WormsCursor.App/       Tray shell (WinForms, no main window)
│  │   ├─ Program.cs                   Entry point (Velopack hook + single-instance guard)
│  │   ├─ TrayApplicationContext.cs   NotifyIcon + menu, owns the engine
│  │   ├─ PreferencesForm.cs          Live settings dialog (size, colours, thickness, radius, test cursor)
│  │   ├─ SingleInstance.cs            One instance only; a 2nd launch opens Preferences
│  │   ├─ Autostart.cs                 "Start with Windows" via HKCU\…\Run
│  │   └─ Services/UpdateService.cs    Velopack check / download / apply updates
│  └─ WormsCursor.Preview/   Console tool — renders the cursor showcase PNGs (docs/README)
│      └─ Program.cs                    Dark + transparent sheets of every themed cursor
└─ tools/
   ├─ generate-icon.py       Builds Assets/Icon.ico (+icon.png) — the arrow glyph
   ├─ pack.ps1               Build a Velopack release locally (Setup.exe + Portable.zip)
   ├─ RELEASING.md           How to cut a release
   └─ RestoreCursor.ps1      Emergency restore of default cursors

The app/tray icon is the same arrow as a white glyph with a black frame (so it reads on both dark and light taskbars), generated by tools/generate-icon.py (Pillow). Regenerate after tweaking the shape/angle:

python tools/generate-icon.py

The engine (Core) is deliberately UI-agnostic, so the tray shell could later be swapped for WPF/WinUI — or packaged for the Microsoft Store — without touching the cursor logic.

Build & run

Requires the .NET 8 SDK (Windows). Open WormsCursor.sln in Visual Studio 2022+ and run, or from a terminal:

dotnet build WormsCursor.sln
dotnet run --project src/WormsCursor.App

A tray icon appears. Right-click it for Enabled / Start with Windows / Preferences… / Check for updates… / Exit; double-click toggles the effect on/off. Only one instance runs — launching it again just opens Preferences. "Start with Windows" registers a per-user HKCU\…\Run entry (no admin), which you can also manage from Task Manager → Startup apps.

Preferences… opens a live editor for cursor size, fill and outline colour, outline thickness and corner radius, with a live preview of all the cursors, a Test cursor picker that forces a chosen cursor on screen, and Apply / Defaults / Check for updates buttons. Settings are saved to %LocalAppData%\WormsCursor\settings.json and persist across restarts — and across updates, since they live outside the app folder.

Standalone build (no .NET install on the target)

dotnet publish src/WormsCursor.App -c Release -r win-x64 --self-contained true -p:PublishSingleFile=true

Note: WinForms doesn't support trimming/NativeAOT, so a self-contained build is several tens of MB. A framework-dependent build is tiny but needs the .NET 8 Desktop Runtime installed.

Releases

Installers and standalone builds are produced by Velopack: pushing a v* tag runs the release workflow (.github/workflows/release.yml), which publishes a Setup.exe installer, a Portable.zip standalone, and delta packages to the repo's GitHub Releases. To build one locally see tools/RELEASING.md (pwsh tools/pack.ps1 -Version x.y.z). The app auto-updates from these releases (tray → Check for updates…, or the button in Preferences).

License

MIT © 2026 Dawid Wenderski