[ios] Fixed entering tracking mode at launch

Entering user tracking mode at launch now zooms in and shows the user dot or user puck. The user dot’s heading indicator now points in the correct direction during the animation to the initial location. Course changes are reflected immediately even in the absence of location changes.

Fixes #1145.

3 files changed, 37 insertions, 23 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 3561c9f9e1..0d6f10b62f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -55,6 +55,8 @@ Known issues:
 - MGLMapCamera’s `altitude` values now match those of MKMapCamera. ([#3362](https://github.com/mapbox/mapbox-gl-native/pull/3362))
 - MGLMapView properties like `centerCoordinate` and `camera` now offset the center to account for any translucent top or bottom bar. As a result, when user tracking is enabled and the map view is an immediate child of a view controller, the user dot is centered in the unobscured portion of the map view. To override this offset, modify the `contentInset` property; you may also need to set the containing view controller’s `automaticallyAdjustsScrollViewInsets` property to `NO`. ([#3583](https://github.com/mapbox/mapbox-gl-native/pull/3583))
 - In user tracking mode, the user dot stays in a fixed position within MGLMapView while the map pans smoothly. A new property, `userLocationVerticalAlignment`, determines the user dot’s fixed position. ([#3589](https://github.com/mapbox/mapbox-gl-native/pull/3589))
+- When the user tracking mode is set to `MGLUserTrackingModeFollowWithCourse`, an optional `targetCoordinate` is kept within sight at all times as the user changes location. This property, in conjunction with the `userLocationVerticalAlignment` property, may be useful for displaying the user’s progress toward a waypoint. ([#3680](https://github.com/mapbox/mapbox-gl-native/pull/3680))
+- Heading or course tracking mode can now be enabled as soon as an MGLMapView is initialized. ([#3680](https://github.com/mapbox/mapbox-gl-native/pull/3680))
 - Zooming and rotation gestures no longer disable user tracking mode. ([#3589](https://github.com/mapbox/mapbox-gl-native/pull/3589))
 - User tracking mode starts out at a lower zoom level by default. ([#3589](https://github.com/mapbox/mapbox-gl-native/pull/3589))
 - Fixed an issue with small map views not properly fitting annotations within bounds. (#[3407](https://github.com/mapbox/mapbox-gl-native/pull/3407))
diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index db93488abe..d499dc7474 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -2993,6 +2993,7 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
     if ( ! [newAnnotationView isEqual:_userLocationAnnotationView])
     {
         _userLocationAnnotationView = newAnnotationView;
+        [self updateUserLocationAnnotationView];
     }
 }
 
@@ -3040,15 +3041,7 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
 
     _userTrackingMode = mode;
     
-    if (_userTrackingMode == MGLUserTrackingModeNone
-        || _userTrackingMode == MGLUserTrackingModeFollowWithCourse)
-    {
-        self.userTrackingState = MGLUserTrackingStatePossible;
-    }
-    if ( ! animated)
-    {
-        self.userTrackingState = MGLUserTrackingStateChanged;
-    }
+    self.userTrackingState = animated ? MGLUserTrackingStatePossible : MGLUserTrackingStateChanged;
 
     switch (_userTrackingMode)
     {
@@ -3150,9 +3143,10 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
 
     if ( ! _showsUserLocation || ! newLocation || ! CLLocationCoordinate2DIsValid(newLocation.coordinate)) return;
 
-    if (! oldLocation || ! CLLocationCoordinate2DIsValid(oldLocation.coordinate) || [newLocation distanceFromLocation:oldLocation])
+    if (! oldLocation || ! CLLocationCoordinate2DIsValid(oldLocation.coordinate) || [newLocation distanceFromLocation:oldLocation]
+        || oldLocation.course != newLocation.course)
     {
-        if (self.userTrackingState != MGLUserTrackingStateBegan)
+        if ( ! oldLocation || ! CLLocationCoordinate2DIsValid(oldLocation.coordinate) || self.userTrackingState != MGLUserTrackingStateBegan)
         {
             self.userLocation.location = newLocation;
         }
@@ -3163,10 +3157,7 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
         }
     }
 
-    if (self.userTrackingMode != MGLUserTrackingModeNone)
-    {
-        [self didUpdateLocationWithUserTrackingAnimated:animated];
-    }
+    [self didUpdateLocationWithUserTrackingAnimated:animated];
 
     self.userLocationAnnotationView.haloLayer.hidden = ! CLLocationCoordinate2DIsValid(self.userLocation.coordinate) ||
         newLocation.horizontalAccuracy > 10;
@@ -3176,11 +3167,20 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
 
 - (void)didUpdateLocationWithUserTrackingAnimated:(BOOL)animated
 {
+    CLLocation *location = self.userLocation.location;
+    if ( ! _showsUserLocation || ! location
+        || ! CLLocationCoordinate2DIsValid(location.coordinate)
+        || self.userTrackingMode == MGLUserTrackingModeNone)
+    {
+        return;
+    }
+    
     // If the user location annotation is already where it’s supposed to be,
     // don’t change the viewport.
     CGPoint correctPoint = self.userLocationAnnotationViewCenter;
     CGPoint currentPoint = [self convertCoordinate:self.userLocation.coordinate toPointToView:self];
-    if (std::abs(currentPoint.x - correctPoint.x) <= 1.0 && std::abs(currentPoint.y - correctPoint.y) <= 1.0)
+    if (std::abs(currentPoint.x - correctPoint.x) <= 1.0 && std::abs(currentPoint.y - correctPoint.y) <= 1.0
+        && self.userTrackingMode != MGLUserTrackingModeFollowWithCourse)
     {
         return;
     }
@@ -3242,7 +3242,10 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
           peakAltitude:-1
      completionHandler:^{
         MGLMapView *strongSelf = weakSelf;
-        strongSelf.userTrackingState = MGLUserTrackingStateChanged;
+        if (strongSelf.userTrackingState == MGLUserTrackingStateBegan)
+        {
+            strongSelf.userTrackingState = MGLUserTrackingStateChanged;
+        }
     }];
 }
 
@@ -3258,7 +3261,10 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
         __weak MGLMapView *weakSelf = self;
         completion = ^{
             MGLMapView *strongSelf = weakSelf;
-            strongSelf.userTrackingState = MGLUserTrackingStateChanged;
+            if (strongSelf.userTrackingState == MGLUserTrackingStateBegan)
+            {
+                strongSelf.userTrackingState = MGLUserTrackingStateChanged;
+            }
         };
     }
     
@@ -3361,7 +3367,8 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
 
     CLLocationDirection headingDirection = (newHeading.trueHeading >= 0 ? newHeading.trueHeading : newHeading.magneticHeading);
 
-    if (headingDirection >= 0 && self.userTrackingMode == MGLUserTrackingModeFollowWithHeading)
+    if (headingDirection >= 0 && self.userTrackingMode == MGLUserTrackingModeFollowWithHeading
+        && self.userTrackingState != MGLUserTrackingStateBegan)
     {
         [self _setDirection:headingDirection animated:YES];
     }
@@ -3455,7 +3462,8 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
 /// Rotate back to true north if the map view is zoomed too far out.
 - (void)unrotateIfNeededAnimated:(BOOL)animated
 {
-    if (self.direction != 0 && ! self.isRotationAllowed)
+    if (self.direction != 0 && ! self.isRotationAllowed
+        && self.userTrackingState != MGLUserTrackingStateBegan)
     {
         if (animated)
         {
@@ -3595,7 +3603,7 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
 {
     MGLUserLocationAnnotationView *annotationView = self.userLocationAnnotationView;
     if ( ! CLLocationCoordinate2DIsValid(self.userLocation.coordinate)) {
-        annotationView.layer.hidden = YES;
+        annotationView.hidden = YES;
         return;
     }
 
@@ -3616,7 +3624,7 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
         -MGLAnnotationUpdateViewportOutset.height), userPoint))
     {
         annotationView.center = userPoint;
-        annotationView.layer.hidden = NO;
+        annotationView.hidden = NO;
         [annotationView setupLayers];
         
         if (_userLocationAnnotationIsSelected)
@@ -3636,7 +3644,7 @@ mbgl::Duration MGLDurationInSeconds(NSTimeInterval duration)
     {
         // User has moved far enough outside of the viewport that showing it or
         // its callout would be useless.
-        annotationView.layer.hidden = YES;
+        annotationView.hidden = YES;
         
         if (_userLocationAnnotationIsSelected)
         {
diff --git a/platform/ios/src/MGLUserLocationAnnotationView.m b/platform/ios/src/MGLUserLocationAnnotationView.m
index 9adbd45f24..b59f4586b3 100644
--- a/platform/ios/src/MGLUserLocationAnnotationView.m
+++ b/platform/ios/src/MGLUserLocationAnnotationView.m
@@ -267,6 +267,10 @@ const CGFloat MGLUserLocationAnnotationArrowSize = MGLUserLocationAnnotationPuck
             _oldHeadingAccuracy = self.annotation.heading.headingAccuracy;
         }
         
+        if (self.annotation.heading.trueHeading >= 0)
+        {
+            _headingIndicatorLayer.affineTransform = CGAffineTransformRotate(CGAffineTransformIdentity, -MGLRadiansFromDegrees(self.mapView.direction - self.annotation.heading.trueHeading));
+        }
     }
     else
     {