Architecture Overview

Pipeline

XDragMover runs as a background menu bar app that installs a global event monitor via the Quartz Event Services API, watching modifier-key and mouse state system-wide. When a qualifying gesture is detected, it resolves the target window through the macOS Accessibility API and drives its position or frame directly.

Global Event Monitor Quartz Event Services

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Event Tap Move / Resize / Focus taps

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Controller Gesture & exclusion logic

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Accessibility API AXUIElement position / size

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Target Window Any other app's window

A shared AppSettings layer (backed by UserDefaults) feeds the active modifier, dwell delay and exclusion patterns into every tap/controller pair live, so changes in Settings apply immediately — no restart required. A StatusMenuController supplies the menu bar item and Settings/Debug windows around this core pipeline.

Stages in detail

Global Event Monitor. A Quartz Event Services tap observes keyboard modifier flags and mouse button/movement events for the entire system, not just this app's own windows.
Event Tap. WindowMoveEventTap/WindowResizeEventTap/FocusFollowsMouseEventTap each compare incoming events against the configured GestureModifier (any combination of Command/Option/Control/Shift except Shift alone) and forward qualifying events to a testable controller.
Controller. WindowMoveController/WindowResizeController resolve which window is under the cursor, check it against the regex-based exclusion list (matched on the owning app's name), and — if not excluded — track mouse deltas for the duration of the drag.
Accessibility API. Position and size changes are applied directly via AXUIElement attributes (AXWindowHandling), the same mechanism System Settings' Accessibility permission gates.
Target Window. The window being moved or resized belongs to whatever app is under the cursor — XDragMover works uniformly across all standard macOS apps, with no per-app integration required.

Permissions

Because it observes input events system-wide and repositions windows belonging to other applications, XDragMover requires the Accessibility permission (System Settings → Privacy & Security → Accessibility), granted once on first launch. No other special entitlements, kernel extensions, or background daemons are used.

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