Stagger new rulers from occupied defaults

Free Ruler/GroupedRulerWindow.swift

@@ -1693,10 +1693,11 @@ final class RulerManager {
         defaults: RulerSettings = RulerSettings(defaults: prefs),
         screenFrame: NSRect = defaultRulerScreenFrame()
     ) -> GroupedRulerController {
-        let state = RulerInstanceState.createFromDefaults(
+        let defaultState = RulerInstanceState.createFromDefaults(
             defaults: defaults,
             screenFrame: screenFrame
         )
+        let state = staggeredState(from: defaultState)
 
         return addRuler(state: state)
     }
@@ -1793,6 +1794,18 @@ final class RulerManager {
         }
     }
 
+    private func staggeredState(from defaultState: RulerInstanceState) -> RulerInstanceState {
+        var state = defaultState
+        let offset = Ruler.thickness / 2
+
+        while controllers.contains(where: { $0.state.layout.zeroPoint == state.layout.zeroPoint }) {
+            state.layout.zeroPoint.x += offset
+            state.layout.zeroPoint.y -= offset
+        }
+
+        return state
+    }
+
     private func notifyStateChanged() {
         onStateChanged?(self)
     }

FreeRulerTests/RulerCoreTests.swift

@@ -169,6 +169,26 @@ final class RulerCoreTests: XCTestCase {
         XCTAssertEqual(manager.states.map(\.settings.unit), [.inches])
     }
 
+    func testRulerManagerStaggersNewRulersWhenDefaultPositionIsOccupied() {
+        let manager = RulerManager()
+        defer {
+            for controller in manager.controllers {
+                controller.hide()
+            }
+        }
+
+        let screenFrame = NSRect(x: 0, y: 0, width: 1000, height: 800)
+        let first = manager.createRuler(screenFrame: screenFrame)
+        let second = manager.createRuler(screenFrame: screenFrame)
+        let third = manager.createRuler(screenFrame: screenFrame)
+        let staggerOffset = Ruler.thickness / 2
+
+        XCTAssertEqual(second.state.layout.zeroPoint.x, first.state.layout.zeroPoint.x + staggerOffset)
+        XCTAssertEqual(second.state.layout.zeroPoint.y, first.state.layout.zeroPoint.y - staggerOffset)
+        XCTAssertEqual(third.state.layout.zeroPoint.x, first.state.layout.zeroPoint.x + (staggerOffset * 2))
+        XCTAssertEqual(third.state.layout.zeroPoint.y, first.state.layout.zeroPoint.y - (staggerOffset * 2))
+    }
+
     func testRulerContextMenuActivatesClickedRulerAndShowsSettingsCommand() {
         withInstalledAppDelegate { appDelegate in
             let manager = appDelegate.rulerManager