TrayZoom

A lightweight Windows system-tray utility that gives you Mac-style smooth full-screen zoom using a hotkey modifier + scroll wheel. The view follows your cursor as you move the mouse while zoomed in.

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Requirements

• Windows 8.1 or later (uses the Windows Magnification API)
• .NET 8 Runtime → https://dotnet.microsoft.com/download/dotnet/8.0 (choose "Run desktop apps" → Windows x64)

Note: TrayZoom runs without administrator rights. The scroll-wheel zoom hook works on all normal desktop windows. It will not intercept input over other processes running as administrator (e.g. Task Manager, UAC dialogs), but this rarely matters in practice.

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Quick start (pre-built binary)

1. Place TrayZoom.exe anywhere you like.
2. Double-click it to run.
3. A magnifier icon appears in the system tray.
4. Hold Win and scroll the mouse wheel to zoom in/out. The view centres on and follows your cursor.
5. Release the Win key; scroll normally at any time.

To exit, right-click the tray icon → Exit. To reset zoom instantly, right-click → Reset Zoom. To change settings, double-click the tray icon or right-click → Settings…

Auto-starting with Windows

TrayZoom does not add itself to startup automatically. To make it start with Windows:

1. Press Win + R and type: shell:startup
2. Create a shortcut to TrayZoom.exe in the folder that opens.

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Command-line options

You can override the hotkey modifier and zoom speed for a single session without touching the saved settings. Useful for scripting or shortcuts.

TrayZoom.exe [--modifier <value>] [--speed <value>] [--help]

Options

--modifier -m <Win|Ctrl|Alt|Ctrl+Alt> Which key to hold while scrolling to trigger zoom. Default: Win

--speed -s <0.05 – 0.40> Animation smoothness. Higher values are snappier. Default: 0.27

--help -h /? Show a quick help dialog and exit.

Examples

TrayZoom.exe --modifier Ctrl --speed 0.30
TrayZoom.exe -m Alt -s 0.15
TrayZoom.exe -m Ctrl+Alt

Command-line values are session-only. They do not overwrite the settings saved via the GUI.

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Settings GUI

Double-click the tray icon (or right-click → Settings…) to open the settings panel.

Setting	Description	Default
Hotkey modifier	Key to hold while scrolling	Win
Zoom step per tick	How much each scroll notch zooms in/out	0.20×
Maximum zoom	Upper zoom limit	8×
Smoothness	Animation speed (Silky → Fast)	~Fast

Click Save to persist settings to the registry under: HKCU\SOFTWARE\TrayZoom

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Building from source

Prerequisites

• Windows 10 or 11
• .NET 8 SDK → https://dotnet.microsoft.com/download/dotnet/8.0 (choose "Build apps" → SDK → Windows x64)

Steps

1. Unzip the project folder.

2. Double-click build.bat — or open a terminal in the project folder and run:

   dotnet publish -c Release -r win-x64 --self-contained false ^
       -p:PublishSingleFile=true -o .\dist
   

3. The compiled TrayZoom.exe appears in the dist\ folder.

4. Double-click it to run (see Quick start above).

Project structure

TrayZoom\
  Program.cs        — all application code (single file)
  TrayZoom.csproj   — .NET 8 WinForms project definition
  app.manifest      — requests admin elevation + DPI awareness
  build.bat         — one-click build script
  README.md         — this file

Modifying the code

All logic lives in Program.cs. Key areas:

• Program.Main() — command-line argument parsing
• TrayZoomApp — hook installation, zoom logic, tray menu
• TrayZoomApp.SmoothTick() — the 60 fps timer that lerps zoom and repositions the view to follow the cursor
• TrayZoomApp.ApplyZoom() — calls MagSetFullscreenTransform
• SettingsForm — the dark-themed settings dialog

The default zoom speed is set by the _smoothSpeed field (0.27). The default zoom step per scroll tick is _zoomStep (0.20).

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Troubleshooting

Nothing happens when I scroll

• Some security software blocks low-level input hooks; try adding an exception for TrayZoom.exe.
• The hook does not intercept input over windows running as administrator (e.g. Task Manager). This is a Windows limitation for non-elevated apps.

"Could not initialise the Windows Magnification API"

• Confirm you are on Windows 8.1 or later.
• Ensure magnification.dll is present in C:\Windows\System32.

Zoom looks blurry

• This is a limitation of the Windows Magnification API at very high zoom levels. Try keeping the zoom below 4×.

The tray icon is missing

• It may be hidden. Click the ^ arrow in the taskbar notification area to reveal hidden tray icons.

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Licence

Do whatever you like with this code. No warranty is provided.