FBAnnotationClusteringSwift

This is a Swift translation of FBAnnotationClustering. Aggregates map pins into a single numbered cluster.

Map clustering is a common enough map feature in modern apps. When I couldn't find a Swift library, I ended up translating one from Objective-C. The library of choice was FBAnnotationClustering (FB stands for Filip Bec, not Facebook). I wanted something that was fast (QuadTree), with a light code base in case I had to figure out and troubleshoot an edge case down the road.

(left: sample project with a lot of pins in the DC area. right: ribl screenshot using clusters)

Installation

This uses just file copy. No CocoaPod implementation.

Copy the following Swift files to your project:

• FBClusteringManager.swift
• FBAnnotationCluster.swift
• FBAnnotationClusterView.swift
• FBAnnotation.swift
• FBQuadTree.swift
• FBQuadTreeNode.swift
• FBBoundingBox.swift

Also make sure you have images in your Images.xcassets named:

• "clusterLarge"
• "clusterMedium"
• "clusterSmall"

These image names are hard-coded in FBAnnotationClusterView.swift, and give you different sized circles based on the number of pins in that cluster.

Usage

Use FBViewController.swift as a guide. For demonstration purposes, it drops 1000 random pins near Ghana.

Follow instructions below for a barely-working implementation.

Step 1: Get a handle to the clustering manager

let clusteringManager = FBClusteringManager()

Step 2: Feed pins into the clustering manager

var array:[FBAnnotation] = []

// drop two arbitrary pins somewhere near Louisville, Kentucky
let pinOne = FBAnnotation()
pinOne.coordinate = CLLocationCoordinate2D(latitude: 38.188805, longitude: -85.6767705)

let pinTwo = FBAnnotation()
pinTwo.coordinate = CLLocationCoordinate2D(latitude: 38.188806, longitude: -85.6767707)

array.append(pinOne)
array.append(pinTwo)

clusteringManager.addAnnotations(array)

Step 3: Wire up your map

Add this to the top of your ViewController:

import MapKit

Add a MapKit View in the Storyboard, and set the delegate.

Step 4: Return either a cluster or a pin in the MKMapViewDelegate

Drop in these MKMapViewDelegate methods:

extension ViewController: MKMapViewDelegate {

    func mapView(mapView: MKMapView!, regionDidChangeAnimated animated: Bool){
        NSOperationQueue().addOperationWithBlock({
            let mapBoundsWidth = Double(self.mapView.bounds.size.width)
            let mapRectWidth:Double = self.mapView.visibleMapRect.size.width
            let scale:Double = mapBoundsWidth / mapRectWidth
            let annotationArray = self.clusteringManager.clusteredAnnotationsWithinMapRect(self.mapView.visibleMapRect, withZoomScale:scale)
            self.clusteringManager.displayAnnotations(annotationArray, onMapView:self.mapView)
        })
    }
    
    func mapView(mapView: MKMapView!, viewForAnnotation annotation: MKAnnotation!) -> MKAnnotationView! {
        var reuseId = ""
        if annotation.isKindOfClass(FBAnnotationCluster) {
            reuseId = "Cluster"
            var clusterView = mapView.dequeueReusableAnnotationViewWithIdentifier(reuseId)
            clusterView = FBAnnotationClusterView(annotation: annotation, reuseIdentifier: reuseId)
            return clusterView
        } else {
            reuseId = "Pin"
            var pinView = mapView.dequeueReusableAnnotationViewWithIdentifier(reuseId) as? MKPinAnnotationView
            pinView = MKPinAnnotationView(annotation: annotation, reuseIdentifier: reuseId)
            pinView!.pinColor = .Green
            return pinView
        }
    }
    
}