RectangleMirrorHow to share part of your screen on a Mac
Meeting apps on the Mac offer two choices, a whole display or a single window. This is how to get the third one: a region.
Why a region
A whole display shows everything, including the things you would rather keep to yourself, and on a large monitor it arrives too small to read. A single window is readable, but the share stops being useful the moment you switch to another app. A region is a fixed part of the screen: whatever you drag into it is shared, whatever stays outside is not.
The steps
- Install RectangleMirror and grant Screen Recording when macOS asks.
- Open its menu in the menu bar and switch on Mirroring. Under Mirror Region choose a half, a third or the full screen, or pick Draw Custom Region and drag out any rectangle.
- In your meeting app start a screen share and choose window sharing. Pick the window named RectangleMirror.
- Carry on working. Move windows in and out of the region; change region from the menu or with ⌃⌥⌘. without stopping the share.
Good to know
- The mirror window is hidden on your own screen so it never covers your work. Meeting apps still list it.
- Save a drawn region by name and set it as the default for a display, so one hotkey starts it.
- This works in any app that can share one window: Zoom, Microsoft Teams, Google Meet, Webex, Slack, Discord.
Free for 14 days, then from $0.99 a month. macOS 14 or later.