public List <IMKAnnotation> ClusteredAnnotationsWithinMapRect(MKMapRect rect, double zoomScale, Dictionary <IMKAnnotation, bool> filter)
{
double cellSize = FBCellSizeForZoomScale(zoomScale);
if (RespondsToSelector != null)
{
cellSize *= RespondsToSelector(this);
}
double scaleFactor = zoomScale / cellSize;
int minX = (int)Math.Floor(rect.MinX * scaleFactor);
int maxX = (int)Math.Floor(rect.MaxX * scaleFactor);
int minY = (int)Math.Floor(rect.MinY * scaleFactor);
int maxY = (int)Math.Floor(rect.MaxY * scaleFactor);
List <IMKAnnotation> clusteredAnnotations = new List <IMKAnnotation>();
lock (this)
{
for (int x = minX; x <= maxX; x++)
{
for (int y = minY; y <= maxY; y++)
{
MKMapRect mapRect = new MKMapRect(x / scaleFactor, y / scaleFactor, 1.0 / scaleFactor, 1.0 / scaleFactor);
FBBoundingBox mapBox = FBUtils.FBBoundingBoxForMapRect(mapRect);
double totalLatitude = 0;
double totalLongitude = 0;
List <IMKAnnotation> annotations = new List <IMKAnnotation>();
_tree.EnumerateAnnotationsInBox(mapBox, delegate(IMKAnnotation annotation)
{
if (filter == null || filter[annotation])
{
totalLatitude += annotation.Coordinate.Latitude;
totalLongitude += annotation.Coordinate.Longitude;
annotations.Add(annotation);
}
});
int count = annotations.Count;
if (count == 1)
{
clusteredAnnotations.AddRange(annotations);
}
if (count > 1)
{
CLLocationCoordinate2D coordinate = new CLLocationCoordinate2D(totalLatitude / count, totalLongitude / count);
FBAnnotationCluster cluster = new FBAnnotationCluster(coordinate);
cluster.Annotations = annotations;
clusteredAnnotations.Add(cluster);
}
}
}
}
return(clusteredAnnotations);
}
