[ios, macos] fixes #6160: allow updating multipoint coordinates (#6565)

2 files changed, 30 insertions, 0 deletions

diff --git a/platform/ios/CHANGELOG.md b/platform/ios/CHANGELOG.md
index 4a445a075a..07f0a3c89d 100644
--- a/platform/ios/CHANGELOG.md
+++ b/platform/ios/CHANGELOG.md
@@ -40,6 +40,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 
 ### Annotations
 
+* MGLPolyline annotations and the exterior coordinates of MGLPolygon annotations are now able to be mutated, part or all, and changes are displayed immediately. ([#6565](https://github.com/mapbox/mapbox-gl-native/pull/6565))
 * Fixed an issue preventing MGLAnnotationView from animating when its coordinate changes. ([#6215](https://github.com/mapbox/mapbox-gl-native/pull/6215))
 * Fixed an issue causing the wrong annotation view to be selected when tapping an annotation view with a center offset applied. ([#5931](https://github.com/mapbox/mapbox-gl-native/pull/5931))
 * Fixed an issue that assigned annotation views to polyline and polygon annotations. ([#5770](https://github.com/mapbox/mapbox-gl-native/pull/5770))
diff --git a/platform/ios/src/MGLMapView.mm b/platform/ios/src/MGLMapView.mm
index bc11303ee8..9067efc033 100644
--- a/platform/ios/src/MGLMapView.mm
+++ b/platform/ios/src/MGLMapView.mm
@@ -1795,6 +1795,29 @@ public:
             }
         }
     }
+    else if ([keyPath isEqualToString:@"coordinates"] && [object isKindOfClass:[MGLMultiPoint class]])
+    {
+        MGLMultiPoint *annotation = object;
+        MGLAnnotationTag annotationTag = (MGLAnnotationTag)(NSUInteger)context;
+        // We can get here because a subclass registered itself as an observer
+        // of the coordinates key path of a multipoint annotation but failed
+        // to handle the change. This check deters us from treating the
+        // subclass’s context as an annotation tag. If the context happens to
+        // match a valid annotation tag, the annotation will be unnecessarily
+        // but safely updated.
+        if (annotation == [self annotationWithTag:annotationTag])
+        {
+            // Update the annotation’s backing geometry to match the annotation model object.
+            _mbglMap->updateAnnotation(annotationTag, [annotation annotationObjectWithDelegate:self]);
+
+            // We don't current support shape multipoint annotation selection, but let's make sure
+            // deselection is handled just to avoid problems in the future.
+            if (annotationTag == _selectedAnnotationTag)
+            {
+                [self deselectAnnotation:annotation animated:YES];
+            }
+        }
+    }
 }
 
 + (NS_SET_OF(NSString *) *)keyPathsForValuesAffectingZoomEnabled
@@ -2840,6 +2863,8 @@ public:
             MGLAnnotationContext context;
             context.annotation = annotation;
             _annotationContextsByAnnotationTag[annotationTag] = context;
+
+            [(NSObject *)annotation addObserver:self forKeyPath:@"coordinates" options:0 context:(void *)(NSUInteger)annotationTag];
         }
         else if ( ! [annotation isKindOfClass:[MGLMultiPolyline class]]
                  || ![annotation isKindOfClass:[MGLMultiPolygon class]]
@@ -3132,6 +3157,10 @@ public:
         {
             [(NSObject *)annotation removeObserver:self forKeyPath:@"coordinate" context:(void *)(NSUInteger)annotationTag];
         }
+        else if ([annotation isKindOfClass:[MGLMultiPoint class]])
+        {
+            [(NSObject *)annotation removeObserver:self forKeyPath:@"coordinates" context:(void *)(NSUInteger)annotationTag];
+        }
 
         _mbglMap->removeAnnotation(annotationTag);
     }