UIImage animation over mapkit overlay

Question

I'm trying to animate a series of radar images over a map of the US. I have a list of radar gif images downloaded from the NOAA website.

How can I implement an animation of a series of images on a mapkit Overlay? I've seen these posts here: Animated MKOverlayView and Animating an MKOverlayView

but couldn't find a solution.

score 1 · Answer 1 · edited Jan 22 '14 at 19:36

1

Here is the best solution for iOS7. MKOverlayRenderer made it very difficult to add animations to the MKMapkit. Follow the example from this project.

edited Jan 22 '14 at 19:36

Unheilig

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answered Jan 22 '14 at 19:23

jhurray

81
4

score 0 · Accepted Answer · answered May 14 '14 at 16:18

I solved the problem by creating a timer in my view controller. Each time the timer fires it calls the setNeedsDisplay method for my custom MKOverlayRenderer. In the renderer subclass drawMapRect method, I have the following code to update the image on the overlay:

-(void)drawMapRect:(MKMapRect)mapRect zoomScale:(MKZoomScale)zoomScale inContext:(CGContextRef)context{
    if (!weatherDataStore) //This is the store where I have my radar images
        weatherDataStore = [WeatherDataStore sharedInstance];

    UIImage *image = [weatherDataStore currentRadarImage];
    if (!image || ![image isKindOfClass:[UIImage class]]) {
        return;
    }

    CGImageRef imageReference = image.CGImage;
    CGContextSetAlpha(context, 0.8);
    MKMapRect theMapRect = [self.overlay boundingMapRect];
    CGRect theRect = [self rectForMapRect:theMapRect];

    CGContextScaleCTM(context, 1.0, -1.0);
    CGContextTranslateCTM(context, 0.0, -theRect.size.height);

    CGContextDrawImage(context, theRect, imageReference);
}

score 0 · Answer 3 · answered Apr 12 '18 at 17:10

SWIFT

Add image as overlay by subclassing MKOverlay and MKOverlarRenderer

MapOverlay.swift

import UIKit
import MapKit

    class MapOverlay: NSObject, MKOverlay {

        var coordinate: CLLocationCoordinate2D
        var boundingMapRect: MKMapRect

        init(coord: CLLocationCoordinate2D, rect: MKMapRect) {
            self.coordinate = coord
            self.boundingMapRect = rect
        }
    }

MapOverlayView.swift

import UIKit
import MapKit

class MapOverlayView: MKOverlayRenderer {

    var overlayImage: UIImage

    init(overlay: MKOverlay, overlayImage:UIImage) {
        self.overlayImage = overlayImage
        super.init(overlay: overlay)
    }

    override func draw(_ mapRect: MKMapRect, zoomScale: MKZoomScale, in context: CGContext) {
        let mapImage = overlayImage.cgImage
        let mapRect = rect(for: overlay.boundingMapRect)
        context.scaleBy(x: 1.0, y: -1.0)
        context.translateBy(x: 0.0, y: -mapRect.size.height)
        context.draw(mapImage!, in: mapRect)
    }
}

ViewController.swift

import UIKit
import MapKit

class ViewController: UIViewController {

    @IBOutlet weak var mapview: MKMapView!

    override func viewDidLoad() {
        super.viewDidLoad()
        mapview.delegate = self

        let location = CLLocationCoordinate2D(latitude: 47.6062, longitude: -122.3320)
        let span = MKCoordinateSpanMake(2.0, 2.0)
        let region = MKCoordinateRegion(center: location, span: span)
        mapview.setRegion(region, animated: true)

        let rec = should be same as your image size 
        let overlay = MapOverlay(coord: location, rect: rec)
        mapview.add(overlay)
    }

}



extension ViewController: MKMapViewDelegate {

    func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {

        if overlay is MapOverlay {
            let logo = UIImage(named: "swift")
            let overlayView = MapOverlayView(overlay: overlay, overlayImage: logo)
            return overlayView
        } else {
            return MKPolylineRenderer()
        }
    }
}

After this call a function to toggle alpha value of MKOverlayRenderer.

The project is available in github : link

UIImage animation over mapkit overlay

3 Answers3