[ios] keep callout view open when panning

platform/ios/CHANGELOG.md

@@ -54,6 +54,7 @@ Mapbox welcomes participation and contributions from everyone. Please read [CONT
 * 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))
+* Fixed an issue causing the callout view to be dismissed when panning around. ([#6676](https://github.com/mapbox/mapbox-gl-native/pull/6676))
 * Per documentation, the first and last coordinates in an MGLPolygon must be identical in order for the polygon to draw correctly. The same is true for an MGLPolygon’s interior polygon. ([#5514](https://github.com/mapbox/mapbox-gl-native/pull/5514))
 * To make an MGLPolyline or MGLPolygon span the antimeridian, specify coordinates with longitudes greater than 180° or less than −180°. ([#6088](https://github.com/mapbox/mapbox-gl-native/pull/6088))
 * Deprecated `-[MGLMapViewDelegate mapView:alphaForShapeAnnotation:]` in favor of specifying an alpha component via `-[MGLMapViewDelegate mapView:strokeColorForShapeAnnotation:]` or `-[MGLMapViewDelegate mapView:fillColorForPolygonAnnotation:]`. ([#6706](https://github.com/mapbox/mapbox-gl-native/pull/6706))

platform/ios/src/MGLMapView.mm

@@ -4554,7 +4554,23 @@ - (void)notifyMapChange:(mbgl::MapChange)change
                 || self.userTrackingMode == MGLUserTrackingModeNone
                 || self.userTrackingState != MGLUserTrackingStateChanged)
             {
-                [self deselectAnnotation:self.selectedAnnotation animated:NO];
+                // Deselect annotation if it lies outside the viewport
+                if (self.selectedAnnotation) {
+                    MGLAnnotationTag tag = [self annotationTagForAnnotation:self.selectedAnnotation];
+                    MGLAnnotationContext &annotationContext = _annotationContextsByAnnotationTag.at(tag);
+                    MGLAnnotationView *annotationView = annotationContext.annotationView;
+
+                    CGRect rect = [self positioningRectForCalloutForAnnotationWithTag:tag];
+
+                    if (annotationView)
+                    {
+                        rect = annotationView.frame;
+                    }
+
+                    if ( ! CGRectIntersectsRect(rect, self.frame)) {
+                        [self deselectAnnotation:self.selectedAnnotation animated:NO];
+                    }
+                }
             }
 
             if ( ! [self isSuppressingChangeDelimiters] && [self.delegate respondsToSelector:@selector(mapView:regionWillChangeAnimated:)])
@@ -4653,6 +4669,7 @@ - (void)notifyMapChange:(mbgl::MapChange)change
                 [self.style didChangeValueForKey:@"layers"];
             }
             [self updateAnnotationViews];
+            [self updateCalloutView];
             if ([self.delegate respondsToSelector:@selector(mapViewDidFinishRenderingFrame:fullyRendered:)])
             {
                 [self.delegate mapViewDidFinishRenderingFrame:self fullyRendered:(change == mbgl::MapChangeDidFinishRenderingFrameFullyRendered)];
@@ -4788,6 +4805,36 @@ - (void)updateAnnotationViews
     [CATransaction commit];
 }
 
+- (void)updateCalloutView
+{
+    [CATransaction begin];
+
+    UIView <MGLCalloutView> *calloutView = self.calloutViewForSelectedAnnotation;
+    id <MGLAnnotation> annotation = calloutView.representedObject;
+
+    if (calloutView && annotation)
+    {
+        MGLAnnotationTag tag = [self annotationTagForAnnotation:annotation];
+        MGLAnnotationContext &annotationContext = _annotationContextsByAnnotationTag.at(tag);
+        MGLAnnotationView *annotationView = annotationContext.annotationView;
+
+        CGRect rect = [self positioningRectForCalloutForAnnotationWithTag:tag];
+
+        if (annotationView)
+        {
+            rect = annotationView.frame;
+        }
+
+        CGPoint point = CGPointMake(CGRectGetMidX(rect), CGRectGetMinY(rect));
+
+        if ( ! CGPointEqualToPoint(calloutView.center, point)) {
+            calloutView.center = point;
+        }
+    }
+
+    [CATransaction commit];
+}
+
 - (void)enqueueAnnotationViewForAnnotationContext:(MGLAnnotationContext &)annotationContext
 {
     MGLAnnotationView *annotationView = annotationContext.annotationView;