[core] [iOS] Completion handlers for animated methods

Added transition frame and finish functions to CameraOptions. Added Objective-C equivalents to the three main entry points to easeTo() in MGLMapView.

Fixes #1581.

1 files changed, 46 insertions, 6 deletions

diff --git a/platform/ios/MGLMapView.mm b/platform/ios/MGLMapView.mm
index 452b307575..c923adb160 100644
--- a/platform/ios/MGLMapView.mm
+++ b/platform/ios/MGLMapView.mm
@@ -1565,14 +1565,18 @@ std::chrono::steady_clock::duration durationInSeconds(float duration)
     [self setCenterCoordinate:centerCoordinate zoomLevel:zoomLevel direction:self.direction animated:animated];
 }
 
-- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate zoomLevel:(double)zoomLevel direction:(CLLocationDirection)direction animated:(BOOL)animated
+- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate zoomLevel:(double)zoomLevel direction:(CLLocationDirection)direction animated:(BOOL)animated {
+    [self setCenterCoordinate:centerCoordinate zoomLevel:zoomLevel direction:direction animated:animated completionHandler:NULL];
+}
+
+- (void)setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate zoomLevel:(double)zoomLevel direction:(CLLocationDirection)direction animated:(BOOL)animated completionHandler:(nullable void (^)(void))completion
 {
     self.userTrackingMode = MGLUserTrackingModeNone;
 
-    [self _setCenterCoordinate:centerCoordinate zoomLevel:zoomLevel direction:direction animated:animated];
+    [self _setCenterCoordinate:centerCoordinate zoomLevel:zoomLevel direction:direction animated:animated completionHandler:completion];
 }
 
-- (void)_setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate zoomLevel:(double)zoomLevel direction:(CLLocationDirection)direction animated:(BOOL)animated
+- (void)_setCenterCoordinate:(CLLocationCoordinate2D)centerCoordinate zoomLevel:(double)zoomLevel direction:(CLLocationDirection)direction animated:(BOOL)animated completionHandler:(nullable void (^)(void))completion
 {
     _mbglMap->cancelTransitions();
     
@@ -1589,6 +1593,17 @@ std::chrono::steady_clock::duration durationInSeconds(float duration)
         options.duration = durationInSeconds(duration);
         options.easing = MGLUnitBezierForMediaTimingFunction(nil);
     }
+    if (completion)
+    {
+        options.transitionFinishFn = [completion]() {
+            // Must run asynchronously after the transition is completely over.
+            // Otherwise, a call to -setCenterCoordinate: within the completion
+            // handler would reenter the completion handler’s caller.
+            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+                completion();
+            });
+        };
+    }
     _mbglMap->easeTo(options);
 
     [self unrotateIfNeededAnimated:animated];
@@ -1679,7 +1694,11 @@ mbgl::LatLngBounds MGLLatLngBoundsFromCoordinateBounds(MGLCoordinateBounds coord
     [self setVisibleCoordinates:coordinates count:count edgePadding:insets direction:direction duration:animated ? MGLAnimationDuration : 0 animationTimingFunction:nil];
 }
 
-- (void)setVisibleCoordinates:(CLLocationCoordinate2D *)coordinates count:(NSUInteger)count edgePadding:(UIEdgeInsets)insets direction:(CLLocationDirection)direction duration:(NSTimeInterval)duration animationTimingFunction:(CAMediaTimingFunction *)function
+- (void)setVisibleCoordinates:(CLLocationCoordinate2D *)coordinates count:(NSUInteger)count edgePadding:(UIEdgeInsets)insets direction:(CLLocationDirection)direction duration:(NSTimeInterval)duration animationTimingFunction:(nullable CAMediaTimingFunction *)function {
+    [self setVisibleCoordinates:coordinates count:count edgePadding:insets direction:direction duration:duration animationTimingFunction:function completionHandler:NULL];
+}
+
+- (void)setVisibleCoordinates:(CLLocationCoordinate2D *)coordinates count:(NSUInteger)count edgePadding:(UIEdgeInsets)insets direction:(CLLocationDirection)direction duration:(NSTimeInterval)duration animationTimingFunction:(nullable CAMediaTimingFunction *)function completionHandler:(nullable void (^)(void))completion
 {
     _mbglMap->cancelTransitions();
     
@@ -1702,6 +1721,14 @@ mbgl::LatLngBounds MGLLatLngBoundsFromCoordinateBounds(MGLCoordinateBounds coord
         options.duration = durationInSeconds(duration);
         options.easing = MGLUnitBezierForMediaTimingFunction(function);
     }
+    if (completion)
+    {
+        options.transitionFinishFn = [completion]() {
+            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+                completion();
+            });
+        };
+    }
     _mbglMap->easeTo(options);
     [self didChangeValueForKey:@"visibleCoordinateBounds"];
 
@@ -1815,7 +1842,12 @@ mbgl::LatLngBounds MGLLatLngBoundsFromCoordinateBounds(MGLCoordinateBounds coord
     [self setCamera:camera withDuration:animated ? MGLAnimationDuration : 0 animationTimingFunction:nil];
 }
 
-- (void)setCamera:(MGLMapCamera *)camera withDuration:(NSTimeInterval)duration animationTimingFunction:(CAMediaTimingFunction *)function
+- (void)setCamera:(MGLMapCamera *)camera withDuration:(NSTimeInterval)duration animationTimingFunction:(nullable CAMediaTimingFunction *)function
+{
+    [self setCamera:camera withDuration:duration animationTimingFunction:function completionHandler:NULL];
+}
+
+- (void)setCamera:(MGLMapCamera *)camera withDuration:(NSTimeInterval)duration animationTimingFunction:(nullable CAMediaTimingFunction *)function completionHandler:(nullable void (^)(void))completion
 {
     _mbglMap->cancelTransitions();
     
@@ -1880,6 +1912,14 @@ mbgl::LatLngBounds MGLLatLngBoundsFromCoordinateBounds(MGLCoordinateBounds coord
         options.duration = durationInSeconds(duration);
         options.easing = MGLUnitBezierForMediaTimingFunction(function);
     }
+    if (completion)
+    {
+        options.transitionFinishFn = [completion]() {
+            dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(0 * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{
+                completion();
+            });
+        };
+    }
     _mbglMap->easeTo(options);
 }
 
@@ -2675,7 +2715,7 @@ CLLocationCoordinate2D MGLLocationCoordinate2DFromLatLng(mbgl::LatLng latLng)
             {
                 // at sufficient detail, just re-center the map; don't zoom
                 //
-                [self _setCenterCoordinate:self.userLocation.location.coordinate zoomLevel:self.zoomLevel direction:course animated:YES];
+                [self _setCenterCoordinate:self.userLocation.location.coordinate zoomLevel:self.zoomLevel direction:course animated:YES completionHandler:NULL];
             }
             else
             {