[ios] Refined annotation selection

Decreased hit test padding for annotation selection, since the query no longer depends on it. Fixed an assertion failure when selecting an annotation while the user dot is selected. Fixed an issue where selecting a selected user dot deselected it. Fixed an issue where the user dot’s callout positioning rect was off-center and a little too high.

1 files changed, 22 insertions, 18 deletions

diff --git a/platform/ios/MGLMapView.mm b/platform/ios/MGLMapView.mm
index bbae5c35d9..560e5249d5 100644
--- a/platform/ios/MGLMapView.mm
+++ b/platform/ios/MGLMapView.mm
@@ -64,10 +64,10 @@ static NSString * const MGLDefaultStyleMarkerSymbolName = @"default_marker";
 NSString *const MGLAnnotationSpritePrefix = @"com.mapbox.sprites.";
 
 /// Slop area around the hit testing point, allowing for imprecise annotation selection.
-const CGFloat MGLAnnotationImagePaddingForHitTest = 10;
+const CGFloat MGLAnnotationImagePaddingForHitTest = 5;
 
 /// Distance from the callout’s anchor point to the annotation it points to.
-const CGFloat MGLAnnotationImagePaddingForCallout = 0;
+const CGFloat MGLAnnotationImagePaddingForCallout = 1;
 
 /// Unique identifier representing a single annotation in mbgl.
 typedef uint32_t MGLAnnotationTag;
@@ -1115,16 +1115,19 @@ std::chrono::steady_clock::duration durationInSeconds(float duration)
 
     CGPoint tapPoint = [singleTap locationInView:self];
 
-    if (self.userLocationVisible && ! _userLocationAnnotationIsSelected)
+    if (self.userLocationVisible)
     {
-        NSAssert(_selectedAnnotationTag == MGLAnnotationTagNotFound,
-                 @"Both the user location annotation and an mbgl-backed annotation are selected.");
-        
-        CGRect userLocationRect = CGRectInset({ tapPoint, CGSizeZero }, 15, 15);
+        // Assume that the user is fat-fingering an annotation.
+        CGRect hitRect = CGRectInset({ tapPoint, CGSizeZero },
+                                     -MGLAnnotationImagePaddingForHitTest,
+                                     -MGLAnnotationImagePaddingForHitTest);
 
-        if (CGRectContainsPoint(userLocationRect, [self convertCoordinate:self.userLocation.coordinate toPointToView:self]))
+        if (CGRectIntersectsRect(hitRect, self.userLocationAnnotationView.frame))
         {
-            [self selectAnnotation:self.userLocation animated:YES];
+            if ( ! _userLocationAnnotationIsSelected)
+            {
+                [self selectAnnotation:self.userLocation animated:YES];
+            }
             return;
         }
     }
@@ -2074,7 +2077,7 @@ std::chrono::steady_clock::duration durationInSeconds(float duration)
 /// Returns the annotation tag assigned to the given annotation. Relatively expensive.
 - (MGLAnnotationTag)annotationTagForAnnotation:(id <MGLAnnotation>)annotation
 {
-    if ( ! annotation || _userLocationAnnotationIsSelected)
+    if ( ! annotation || annotation == self.userLocation)
     {
         return MGLAnnotationTagNotFound;
     }
@@ -2367,6 +2370,10 @@ std::chrono::steady_clock::duration durationInSeconds(float duration)
     return self.annotationImagesByIdentifier[identifier];
 }
 
+CLLocationDistance MGLDistanceBetweenCoordinate2Ds(CLLocationCoordinate2D a, CLLocationCoordinate2D b) {
+    return hypot(b.latitude - a.latitude, b.longitude - a.longitude);
+}
+
 /**
     Returns the tag of the annotation at the given point in the view.
 
@@ -2400,14 +2407,10 @@ std::chrono::steady_clock::duration durationInSeconds(float duration)
         
         // Filter out any annotation whose image is unselectable or for which
         // hit testing fails.
-        mbgl::util::erase_if(nearbyAnnotations, [&](const MGLAnnotationTag annotationTag)
+        std::remove_if(nearbyAnnotations.begin(), nearbyAnnotations.end(), [&](const MGLAnnotationTag annotationTag)
         {
-            NSAssert(_annotationContextsByAnnotationTag.count(annotationTag) != 0, @"Unknown annotation found nearby tap");
             id <MGLAnnotation> annotation = [self annotationWithTag:annotationTag];
-            if ( ! annotation)
-            {
-                return true;
-            }
+            NSAssert(annotation, @"Unknown annotation found nearby tap");
             
             MGLAnnotationImage *annotationImage = [self imageOfAnnotationWithTag:annotationTag];
             if ( ! annotationImage.enabled)
@@ -2561,8 +2564,9 @@ std::chrono::steady_clock::duration durationInSeconds(float duration)
 
         if (_userLocationAnnotationIsSelected)
         {
-            CGPoint calloutAnchorPoint = [self convertCoordinate:annotation.coordinate toPointToView:self];
-            positioningRect = CGRectMake(calloutAnchorPoint.x - 1, calloutAnchorPoint.y - 13, 0, 0);
+            positioningRect = CGRectInset(self.userLocationAnnotationView.frame,
+                                          -MGLAnnotationImagePaddingForCallout,
+                                          -MGLAnnotationImagePaddingForCallout);
         }
 
         // consult delegate for left and/or right accessory views