Add configurable threshold for rotate gesture snapping to north (#3914)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: JesseCrocker

platform/ios/src/MLNMapView.h

@@ -855,6 +855,15 @@ vertically on the map.
  */
 @property (nonatomic, getter=isRotateEnabled) BOOL rotateEnabled;
 
+/**
+The threshold, measured in degrees, that determines when the map's bearing will snap to north.
+For example, with a toleranceForSnappingToNorth of 7, if the user rotates the map within 7 degrees
+of north, the map will automatically snap to exact north.
+
+ The default value of this property is 7.
+ */
+@property (nonatomic) CGFloat toleranceForSnappingToNorth;
+
 /**
  A Boolean value that determines whether the user may change the pitch (tilt) of
  the map.

platform/ios/src/MLNMapView.mm

@@ -290,9 +290,6 @@ typedef NS_ENUM(NSUInteger, MLNUserTrackingState) {
 /// Initial zoom level when entering user tracking mode from a low zoom level.
 const double MLNDefaultZoomLevelForUserTracking = 14.0;
 
-/// Tolerance for snapping to true north, measured in degrees in either direction.
-const CLLocationDirection MLNToleranceForSnappingToNorth = 7;
-
 /// Distance threshold to stop the camera while animating.
 const CLLocationDistance MLNDistanceThresholdForCameraPause = 500;
 
@@ -883,6 +880,7 @@ - (void)commonInitWithOptions:(MLNMapOptions*)mlnMapoptions
     [self addGestureRecognizer:_rotate];
     _rotateEnabled = YES;
     _rotationThresholdWhileZooming = 3;
+    _toleranceForSnappingToNorth = 7;
 
     _doubleTap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleDoubleTapGesture:)];
     _doubleTap.numberOfTapsRequired = 2;
@@ -6839,8 +6837,8 @@ - (void)unrotateIfNeededForGesture
         [self unrotateIfNeededAnimated:YES];
 
         // Snap to north.
-        if ((self.direction < MLNToleranceForSnappingToNorth
-             || self.direction > 360 - MLNToleranceForSnappingToNorth)
+        if ((self.direction < self.toleranceForSnappingToNorth
+             || self.direction > 360 - self.toleranceForSnappingToNorth)
             && self.userTrackingMode != MLNUserTrackingModeFollowWithHeading
             && self.userTrackingMode != MLNUserTrackingModeFollowWithCourse)
         {