The Garage SDKs, in the open

garage_auth, garage_entitlements, garage_iap and garage_ui, moved out of
Garage-Services and Metro-Map-Maker into one public repo. MIT, one readme,
docs under docs/.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013F4NWNvYcdeSgqbWMT1VQ7

garage_ui/macos/Classes/CursorLock.swift

@@ -0,0 +1,64 @@
+import Cocoa
+import FlutterMacOS
+
+// Hides the OS cursor and keeps it pinned in place for the duration of a
+// drag, streaming raw pointer deltas back to Dart ourselves.
+//
+// Why not just let Flutters own pointer events drive this: Flutter computes
+// PointerEvent.delta from the ABSOLUTE cursor position of consecutive
+// events, not from raw hardware deltaX/deltaY. An earlier version tried to
+// keep the cursor pinned by warping it back to an anchor point after every
+// move while staying associated in between - that still let the OS visibly
+// move the cursor between warps, and the warps themselves raced against
+// real movement over the async Dart<->native round trip.
+//
+// The actual fix: CGAssociateMouseAndMouseCursorPosition(false) for the
+// WHOLE gesture, not toggled per-event. WindowServer then simply stops
+// moving the on-screen cursor at all in response to hardware input - no
+// per-frame warping needed. mouseDragged events keep firing completely
+// normally while disassociated, with correct deltaX/deltaY reflecting real
+// HID movement (its only locationInWindow that freezes) - which is exactly
+// why we read deltaX/deltaY here instead of position. Re-associating on
+// unlock resumes normal 1:1 tracking from wherever the cursor was frozen,
+// so it naturally reappears back where the drag started.
+final class CursorLock {
+  static let shared = CursorLock()
+
+  private var locked = false
+  private var monitor: Any?
+  // strong on purpose - CursorLock.shared is a permanent singleton, theres
+  // no retain cycle risk, and a weak ref here previously meant the channel
+  // (whose only other strong reference was a local `let` in awakeFromNib)
+  // got deallocated the moment that function returned, silently breaking
+  // delta forwarding.
+  private var channel: FlutterMethodChannel?
+
+  func attach(channel: FlutterMethodChannel) {
+    self.channel = channel
+  }
+
+  func lock() {
+    guard !locked else { return }
+    locked = true
+    NSCursor.hide()
+    CGAssociateMouseAndMouseCursorPosition(0)
+    monitor = NSEvent.addLocalMonitorForEvents(matching: [.leftMouseDragged]) { [weak self] event in
+      guard let self, self.locked else { return event }
+      self.channel?.invokeMethod("scrubDelta", arguments: ["dx": event.deltaX, "dy": event.deltaY])
+      // swallowed - Flutters own position for this event is frozen (and
+      // therefore meaningless) while disassociated, no point forwarding it.
+      return nil
+    }
+  }
+
+  func unlock() {
+    guard locked else { return }
+    locked = false
+    if let monitor {
+      NSEvent.removeMonitor(monitor)
+    }
+    monitor = nil
+    CGAssociateMouseAndMouseCursorPosition(1)
+    NSCursor.unhide()
+  }
+}