Work around pan deceleration on pitched maps (#773)

mapbox · Oct 20, 2021 · 31acae8 · 31acae8
1 parent a8fc21b
commit 31acae8
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Showing 3 changed files with 31 additions and 8 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -8,6 +8,7 @@ Mapbox welcomes participation and contributions from everyone.
 * Set `MapboxMap` flags during gestures and animations. ([#754](https://github.com/mapbox/mapbox-maps-ios/pull/754))
 * Treat anchor as constant for `ease(to:)` animations. ([#772](https://github.com/mapbox/mapbox-maps-ios/pull/772))
 * Fix experimental snapshot API for iOS 15. ([#760](https://github.com/mapbox/mapbox-maps-ios/pull/760))
+* Decelerate more quickly (or not at all) on pitched maps. ([#773](https://github.com/mapbox/mapbox-maps-ios/pull/773))
 
 ## 10.0.1 - October 15, 2021
 

diff --git a/Sources/MapboxMaps/Gestures/GestureHandlers/PanGestureHandler.swift b/Sources/MapboxMaps/Gestures/GestureHandlers/PanGestureHandler.swift
@@ -74,17 +74,21 @@ internal final class PanGestureHandler: GestureHandler, PanGestureHandlerProtoco
             // it without further dragging. This specific time interval
             // is just the result of manual tuning.
             let decelerationTimeout: TimeInterval = 1.0 / 30.0
+            let maxPitchForDeceleration: CGFloat = 60
             guard let initialTouchLocation = initialTouchLocation,
                   let initialCameraState = initialCameraState,
                   let lastChangedDate = lastChangedDate,
-                  dateProvider.now.timeIntervalSince(lastChangedDate) < decelerationTimeout else {
+                  dateProvider.now.timeIntervalSince(lastChangedDate) < decelerationTimeout,
+                  mapboxMap.cameraState.pitch <= maxPitchForDeceleration else {
                 delegate?.gestureEnded(for: .pan, willAnimate: false)
                 return
             }
             cameraAnimationsManager.decelerate(
                 location: touchLocation,
                 velocity: gestureRecognizer.velocity(in: view),
-                decelerationFactor: decelerationFactor,
+                // Decelerate more quickly when pitched. This is a workaround for an issue
+                // in the drag API that we hope to fix in MapboxCoreMaps in a future release.
+                decelerationFactor: decelerationFactor * (1 - mapboxMap.cameraState.pitch / 5000),
                 locationChangeHandler: { (touchLocation) in
                     // here we capture the initial state so that we can clear
                     // it immediately after starting the animation

diff --git a/Tests/MapboxMapsTests/Gestures/GestureHandlers/PanGestureHandlerTests.swift b/Tests/MapboxMapsTests/Gestures/GestureHandlers/PanGestureHandlerTests.swift
@@ -97,7 +97,7 @@ final class PanGestureHandlerTests: XCTestCase {
             clampedTouchLocation: clampedTouchLocation)
     }
 
-    func testHandlePanChangedWithHorizontalPanScrollingMode() throws {
+    func testHandlePanChangedWithHorizontalPanMode() throws {
         let initialTouchLocation = CGPoint.random()
         let changedTouchLocation = CGPoint.random()
         let clampedTouchLocation = CGPoint(
@@ -111,7 +111,7 @@ final class PanGestureHandlerTests: XCTestCase {
             clampedTouchLocation: clampedTouchLocation)
     }
 
-    func testHandlePanChangedWithVerticalPanScrollingMode() throws {
+    func testHandlePanChangedWithVerticalPanMode() throws {
         let initialTouchLocation = CGPoint.random()
         let changedTouchLocation = CGPoint.random()
         let clampedTouchLocation = CGPoint(
@@ -143,7 +143,8 @@ final class PanGestureHandlerTests: XCTestCase {
                               line: UInt = #line) throws {
         panGestureHandler.panMode = panMode
         panGestureHandler.decelerationFactor = .random(in: 0.1...0.99)
-        let initialCameraState = CameraState.random()
+        var initialCameraState = CameraState.random()
+        initialCameraState.pitch = initialCameraState.pitch.clamped(to: 0...60)
         mapboxMap.cameraState = initialCameraState
         let endedTouchLocation = CGPoint.random()
         gestureRecognizer.locationStub.returnValueQueue = [
@@ -172,7 +173,7 @@ final class PanGestureHandlerTests: XCTestCase {
         let decelerateParams = cameraAnimationsManager.decelerateStub.parameters.first
         XCTAssertEqual(decelerateParams?.location, endedTouchLocation, line: line)
         XCTAssertEqual(decelerateParams?.velocity, velocity, line: line)
-        XCTAssertEqual(decelerateParams?.decelerationFactor, panGestureHandler.decelerationFactor, line: line)
+        XCTAssertEqual(decelerateParams?.decelerationFactor, panGestureHandler.decelerationFactor * (1 - initialCameraState.pitch / 5000), line: line)
         let locationChangeHandler = try XCTUnwrap(decelerateParams?.locationChangeHandler)
         locationChangeHandler(interpolatedTouchLocation)
         XCTAssertEqual(mapboxMap.dragStartStub.parameters, [initialTouchLocation], line: line)
@@ -202,7 +203,7 @@ final class PanGestureHandlerTests: XCTestCase {
             clampedTouchLocation: clampedTouchLocation)
     }
 
-    func testHandlePanEndedWithHorizontalPanScrollingMode() throws {
+    func testHandlePanEndedWithHorizontalPanMode() throws {
         let initialTouchLocation = CGPoint.random()
         let interpolatedTouchLocation = CGPoint.random()
         let clampedTouchLocation =  CGPoint(
@@ -216,7 +217,7 @@ final class PanGestureHandlerTests: XCTestCase {
             clampedTouchLocation: clampedTouchLocation)
     }
 
-    func testHandlePanEndedWithVerticalPanScrollingMode() throws {
+    func testHandlePanEndedWithVerticalPanMode() throws {
         let initialTouchLocation = CGPoint.random()
         let interpolatedTouchLocation = CGPoint.random()
         let clampedTouchLocation =  CGPoint(
@@ -230,6 +231,23 @@ final class PanGestureHandlerTests: XCTestCase {
             clampedTouchLocation: clampedTouchLocation)
     }
 
+    func testHandlePanEndedWithPitchGreaterThan60DoesNotDecelerate() throws {
+        mapboxMap.cameraState = .random()
+        mapboxMap.cameraState.pitch = 61
+        gestureRecognizer.getStateStub.defaultReturnValue = .began
+        gestureRecognizer.sendActions()
+        gestureRecognizer.getStateStub.defaultReturnValue = .changed
+        gestureRecognizer.sendActions()
+
+        gestureRecognizer.getStateStub.defaultReturnValue = .ended
+        gestureRecognizer.sendActions()
+
+        XCTAssertEqual(delegate.gestureEndedStub.invocations.count, 1)
+        XCTAssertEqual(delegate.gestureEndedStub.parameters.first?.gestureType, .pan)
+        let willAnimate = try XCTUnwrap(delegate.gestureEndedStub.parameters.first?.willAnimate)
+        XCTAssertFalse(willAnimate)
+    }
+
     func testHandlePanCancelledDoesNotTriggerDecelerationAnimation() throws {
         gestureRecognizer.getStateStub.defaultReturnValue = .cancelled