MapView to show all annotations and zoom in as much as possible of the map

Question

I basically have a map where I add two annotations and they are shown as expected.

Then I´m using the following code:

let annotations = [start, end]
mapView?.showAnnotations(annotations, animated: false)

And this zooms to show my map with the two annotations, but the map could be zoomed in much more and show a more detailed map view.

This is what I get today and this is the expected result that I want.

As you can see the map could be zoomed in a lot more.

Any ideas how to achieve this?

Answer 1

Swift 5.0 / 4.2 version of nyxee's answer

extension MKMapView {

    /// When we call this function, we have already added the annotations to the map, and just want all of them to be displayed.
    func fitAll() {
        var zoomRect            = MKMapRect.null;
        for annotation in annotations {
            let annotationPoint = MKMapPoint(annotation.coordinate)
            let pointRect       = MKMapRect(x: annotationPoint.x, y: annotationPoint.y, width: 0.01, height: 0.01);
            zoomRect            = zoomRect.union(pointRect);
        }
        setVisibleMapRect(zoomRect, edgePadding: UIEdgeInsets(top: 100, left: 100, bottom: 100, right: 100), animated: true)
    }

    /// We call this function and give it the annotations we want added to the map. we display the annotations if necessary
    func fitAll(in annotations: [MKAnnotation], andShow show: Bool) {
        var zoomRect:MKMapRect  = MKMapRect.null
    
        for annotation in annotations {
            let aPoint          = MKMapPoint(annotation.coordinate)
            let rect            = MKMapRect(x: aPoint.x, y: aPoint.y, width: 0.1, height: 0.1)
        
            if zoomRect.isNull {
                zoomRect = rect
            } else {
                zoomRect = zoomRect.union(rect)
            }
        }
        if(show) {
            addAnnotations(annotations)
        }
        setVisibleMapRect(zoomRect, edgePadding: UIEdgeInsets(top: 100, left: 100, bottom: 100, right: 100), animated: true)
    }

}