displayoverride-mac

December 6, 2025 · View on GitHub

A macOS menu bar app to force specific screen resolutions.

Screenshot

Why?

Modern Macs have non-standard display resolutions (e.g. 3024×1964 on a MacBook Pro 16"). This can be problematic for AI computer use models like Claude, which are typically trained on standard resolutions like 1920×1080.

macOS doesn't natively support setting arbitrary resolutions on built-in displays. This app works around that by creating a virtual display at your desired resolution, which you can then mirror your main display to.

Features

  • Create virtual displays at 4K (3840×2160), 1080p (1920×1080), or 720p (1280×720)
  • Menu bar app - no dock icon
  • Switch between resolutions
  • Disable when not needed

Installation

# Clone the repo
git clone git@github.com:domdomegg/displayoverride-mac.git
cd displayoverride-mac

# Build
swiftc -O -o displayoverride DisplayOverride.swift

# Run
./displayoverride

Or download a pre-built binary from the Releases page.

Usage

  1. Launch the app - a 🖥️ icon appears in your menu bar
  2. Click and select a resolution (4K, 1080p, or 720p)
  3. The virtual display appears in System Settings > Displays
  4. Arrange it as needed, or mirror your main display to it
  5. Click "Disable" to remove the virtual display

How it works

Uses the private CGVirtualDisplay API from CoreGraphics to create virtual display outputs. This is the same approach used by apps like BetterDisplay and FluffyDisplay.

Limitations

  • Uses undocumented Apple APIs which could break in future macOS versions
  • Only tested on Apple Silicon Macs