CODEWITHSUNDEEP
iosgoogle-maps
Dave Cole
Dave Cole

Reputation: 2765

Google Maps for iOS - How can you tell if a marker is within the bounds of the screen?

I'm trying to figure out a straightforward way to determine in Google Maps for iOS if a given GMSMarker is within the bounds of the visible map. There seems to be solutions for this in the Javascript API but other than perhaps doing some complex reasoning based on this post there doesn't seem to be a way.

Upvotes: 12

Views: 7783

Answers (5)

Gabriel Wamunyu
Gabriel Wamunyu

Reputation: 754

The swift 4 version of the answer. Returning a boolean if marker is within the screen region or not

func isMarkerWithinScreen(marker: GMSMarker) -> Bool {
    let region = self.mapView.projection.visibleRegion()
    let bounds = GMSCoordinateBounds(region: region)
    return bounds.contains(marker.position)
}

Upvotes: 10

Shelly Pritchard
Shelly Pritchard

Reputation: 11534

I have written on method to find GMSMarker is in particular frame. Set your rectangle frame (x,y,maxX,maxY). You can set any frame from screen it tell find marker is in that frame or not.. 

- (BOOL)isGoogleMapMarkerVisible:(GMSMarker*)marker {

    //Marker point
    CGPoint markerpoint = [self.mapview.projection pointForCoordinate:marker.position];

    //Maximum visible region from x and y axis
    float x = 0.0;
    float y = o.o;
    float maxX = self.mapview.frame.size.width;
    float maxY = self.mapview.frame.size.height;

    //If marker point is on visible region return true else return false
    if (markerpoint.x > x && markerpoint.y > y && markerpoint.x < maxX && markerpoint.y < maxY) {
        return YES;
    }
    else {
            return NO;
    }
}

Upvotes: 1

Mrug
Mrug

Reputation: 5023

Hope this code may help to code hunters.

NSMutableArray *mutArrMarkers; //Have all markers added on Map
.
.
.
.

NSMutableArray *mutArrMarkersInPath = [NSMutableArray array];
[mutArrMarkers enumerateObjectsUsingBlock:^(id  _Nonnull obj, NSUInteger idx, BOOL * _Nonnull stop) {
   GMSMarker *marker = obj;
   if(GMSGeometryContainsLocation(currentCoordinates, pathToCheck, YES)){
        [mutArrMarkersInPath addObject:marker];
   }
}];

Upvotes: 0

Dave Cole
Dave Cole

Reputation: 2765

A code example based on Andy's helpful response:

- (void)snapToMarkerIfItIsOutsideViewport:(GMSMarker *)m{
    GMSVisibleRegion region = _mapView.projection.visibleRegion;
    GMSCoordinateBounds *bounds = [[GMSCoordinateBounds alloc] initWithRegion:region];
    if (![bounds containsCoordinate:m.position]){
        GMSCameraPosition *camera = [GMSCameraPosition cameraWithLatitude:m.position.latitude
                                              longitude:m.position.longitude
                                                   zoom:_mapView.camera.zoom];
        [self.mapView animateToCameraPosition: camera];
    }
}

Upvotes: 18

Andy
Andy

Reputation: 2414

Retrieve the bounds of your viewport with GMSVisibleRegion and create a GMSCoordinateBounds with it. Call containsCoordinate, passing in the marker's position. It should return true if the marker is within the viewport and false if not.

Upvotes: 16

Related Questions