From 218c720e9e8882e3d9070ce72ca3b4173c7835c8 Mon Sep 17 00:00:00 2001
From: Jason Wray <jason@mapbox.com>
Date: Tue, 29 Aug 2017 17:42:38 -0400
Subject: [ios] Add setShowsUserHeadingIndicator and
 validateUserHeadingUpdating

---
 platform/ios/app/MBXViewController.m |  1 +
 platform/ios/src/MGLMapView.h        | 17 +++++++++++++
 platform/ios/src/MGLMapView.mm       | 47 ++++++++++++++++++++++++++----------
 3 files changed, 52 insertions(+), 13 deletions(-)

diff --git a/platform/ios/app/MBXViewController.m b/platform/ios/app/MBXViewController.m
index 40e5889526..6d9eafc042 100644
--- a/platform/ios/app/MBXViewController.m
+++ b/platform/ios/app/MBXViewController.m
@@ -160,6 +160,7 @@ typedef NS_ENUM(NSInteger, MBXSettingsMiscellaneousRows) {
 
     self.debugLoggingEnabled = [[NSUserDefaults standardUserDefaults] boolForKey:@"MGLMapboxMetricsDebugLoggingEnabled"];
     self.mapView.scaleBar.hidden = NO;
+    self.mapView.showsUserHeadingIndicator = YES;
     self.hudLabel.hidden = YES;
     self.hudLabel.titleLabel.font = [UIFont monospacedDigitSystemFontOfSize:10 weight:UIFontWeightRegular];
 
diff --git a/platform/ios/src/MGLMapView.h b/platform/ios/src/MGLMapView.h
index b475a21d2b..16a76ebcfe 100644
--- a/platform/ios/src/MGLMapView.h
+++ b/platform/ios/src/MGLMapView.h
@@ -357,6 +357,23 @@ MGL_EXPORT IB_DESIGNABLE
  */
 - (void)setUserLocationVerticalAlignment:(MGLAnnotationVerticalAlignment)alignment animated:(BOOL)animated;
 
+/**
+ A Boolean value indicating whether the user location annotation may display a
+ permanent heading indicator.
+
+ Setting this property to `YES` causes the default user location annotation to
+ always show an arrow-shaped heading indicator, if heading is available. This
+ property does not rotate the map; for that, see
+ `MGLUserTrackingModeFollowWithHeading`.
+
+ This property has no effect when `userTrackingMode` is
+ `MGLUserTrackingModeFollowWithHeading` or
+ `MGLUserTrackingModeFollowWithCourse`.
+
+ The default value of this property is `NO`.
+ */
+@property (nonatomic, assign) BOOL showsUserHeadingIndicator;
+
 /**
  Whether the map view should display a heading calibration alert when necessary.
  The default value is `YES`.
diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index 320c4bcda8..9f5ccaaa77 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -872,10 +872,14 @@ public:
 
     if (self.compassView.alpha)
     {
-        [self updateHeadingForDeviceOrientation];
         [self updateCompass];
     }
 
+    if (self.compassView.alpha || self.showsUserHeadingIndicator)
+    {
+        [self updateHeadingForDeviceOrientation];
+    }
+
     [self updateUserLocationAnnotationView];
 }
 
@@ -4195,10 +4199,7 @@ public:
         self.locationManager.delegate = self;
         [self.locationManager startUpdatingLocation];
 
-        if (self.userTrackingMode == MGLUserTrackingModeFollowWithHeading)
-        {
-            [self.locationManager startUpdatingHeading];
-        }
+        [self validateUserHeadingUpdating];
     }
     else if ( ! shouldEnableLocationServices && self.locationManager)
     {
@@ -4322,8 +4323,6 @@ public:
         {
             self.userTrackingState = MGLUserTrackingStatePossible;
 
-            [self.locationManager stopUpdatingHeading];
-
             // Immediately update the annotation view; other cases update inside
             // the locationManager:didUpdateLocations: method.
             [self updateUserLocationAnnotationView];
@@ -4336,8 +4335,6 @@ public:
             self.userTrackingState = animated ? MGLUserTrackingStatePossible : MGLUserTrackingStateChanged;
             self.showsUserLocation = YES;
 
-            [self.locationManager stopUpdatingHeading];
-
             break;
         }
         case MGLUserTrackingModeFollowWithHeading:
@@ -4354,10 +4351,6 @@ public:
                 [self setZoomLevel:self.currentMinimumZoom animated:YES];
             }
 
-            [self updateHeadingForDeviceOrientation];
-
-            [self.locationManager startUpdatingHeading];
-
             break;
         }
     }
@@ -4371,6 +4364,8 @@ public:
         }
     }
 
+    [self validateUserHeadingUpdating];
+
     if ([self.delegate respondsToSelector:@selector(mapView:didChangeUserTrackingMode:animated:)])
     {
         [self.delegate mapView:self didChangeUserTrackingMode:_userTrackingMode animated:animated];
@@ -4419,6 +4414,27 @@ public:
     }
 }
 
+- (void)setShowsUserHeadingIndicator:(BOOL)showsUserHeadingIndicator
+{
+    _showsUserHeadingIndicator = showsUserHeadingIndicator;
+    [self validateUserHeadingUpdating];
+}
+
+- (void)validateUserHeadingUpdating
+{
+    BOOL canShowPermanentHeadingIndicator = self.showsUserHeadingIndicator && self.userTrackingMode != MGLUserTrackingModeFollowWithCourse;
+
+    if (self.showsUserLocation && (canShowPermanentHeadingIndicator || self.userTrackingMode == MGLUserTrackingModeFollowWithHeading))
+    {
+        [self updateHeadingForDeviceOrientation];
+        [self.locationManager startUpdatingHeading];
+    }
+    else
+    {
+        [self.locationManager stopUpdatingHeading];
+    }
+}
+
 - (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
 {
     [self locationManager:manager didUpdateLocations:locations animated:YES];
@@ -4666,6 +4682,11 @@ public:
 
     self.userLocation.heading = newHeading;
 
+    if (self.showsUserHeadingIndicator || self.userTrackingMode == MGLUserTrackingModeFollowWithHeading)
+    {
+        [self updateUserLocationAnnotationView];
+    }
+
     if ([self.delegate respondsToSelector:@selector(mapView:didUpdateUserLocation:)])
     {
         [self.delegate mapView:self didUpdateUserLocation:self.userLocation];
-- 
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