MKCoordinateRegion extension to determine region needed to fit a set of locations with zoom factor

gistfile1.swift

extension MKCoordinateRegion {
    static func region(forLocations waypoints: [CLLocation], zoomPercent: Double = 0.2) -> MKCoordinateRegion {
        var r = MKMapRectNull
        
        for wp in waypoints {
            var point = MKMapPointForCoordinate(wp.coordinate)
            r = MKMapRectUnion(r, MKMapRectMake(point.x, point.y, 0, 0))
        }
        
        let zoomed = MKMapRectMake(r.origin.x-r.size.width*zoomPercent, r.origin.y-r.size.height*zoomPercent, r.size.width*(1+zoomPercent*2), r.size.height*(1+zoomPercent*2))
        
        return MKCoordinateRegionForMapRect(zoomed)
    }
}