FB14920414: Add API to detect whether the screen is captured (recorded, shared, or mirrored)

[sindresorhus]

• Date: 2024-08-26
• Resolution: Open
• Area: AppKit
• OS: macOS 14.6
• Type: Suggestion

Description

macOS needs a public API to detect if the screen is being observed (recorded, shared, or mirrored). iOS already offers this with UIScreen.isCaptured. macOS should have a similar capability to ensure consistency across platforms and improve user privacy.

I assume system notifications already use an internal API for this as they have a checkbox called "Allow notifications when mirroring or sharing the display".

Use Cases:

• Sensitive Content Protection: Apps handling confidential or sensitive information can hide or blur content when the screen is being captured, preventing unintended exposure. For example, a calendar app could have a setting to hide event titles when the screen is captured, to avoid leaking private details on a screencast.
• Fullscreen Notifications: Apps that show fullscreen alerts can suppress them when the screen is recorded or mirrored, ensuring privacy during sensitive operations.

Proposed API:

extension NSScreen {
	var isCaptured: Bool {}
}

I looked through the private headers on macOS and found that there already is a private property for this called CGSIsScreenWatcherPresent. So the functionality seems to already exist and just needs to be exposed.