macOS · Desktop

Anchor

Name: Anchor
Author: NoSleepLab

Keep one corner of a window in sight — a live crop of it, floating above whatever you are doing

Source only

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About Anchor

Anchor is built to take any rectangle of your screen and pin it as a floating, always-on-top panel that keeps mirroring the source — a live crop rather than a screenshot. Cmd+Shift+A enters selection mode, you drag a rectangle, and the region is redrawn through CGWindowListCreateImage at up to 15 FPS, dropping to 5 as more anchors open. Several anchors can be open at once, each resizable and with its own opacity, and a region drawn over a window follows that window when it moves. The case for it is a dashboard, a chat window, or reference material you need in view while working somewhere else.

Who it's for

Multi-taskers who need to keep an eye on one thing while working on another.

What it does

Live screen region capture at 5-15 FPS
Multiple simultaneous floating anchors
Resize, move, and adjust opacity per anchor
Window-anchored mode: the capture follows its source window
Right-click: screenshot, zoom, close
FPS throttling based on anchor count

Behind the build

Anchor redraws each pinned region with CGWindowListCreateImage, an API deprecated in macOS 14 and obsoleted in macOS 15 that still compiles here only because the app targets macOS 13.

Each capture goes straight onto a CALayer's contents, at 15 FPS for one anchor, 10 for two or three and 5 for four or more. In window-anchored mode it polls CGWindowListCopyWindowInfo twice a second and moves the capture rectangle with the source window; the panel itself stays put. The move to ScreenCaptureKit is an SCStream over a display filter that excludes Anchor's own panels.

The full write-upCGWindowListCreateImage unavailable in macOS 15: use SCStream

Information

Runs on: macOS · Desktop
Status: Source only
Requires: macOS 13+

Source: Public on GitHub
Telemetry: None
Built with: Swift & SwiftUI

Stack: SwiftUIAppKitCGWindowListCreateImageCALayer

Anchor is source only, for now.

The code is public, but there's no packaged release yet. Build it from the repository today, or leave an email and hear when there's one you can double-click.

Tell me when it ships View source

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