How to add "greater than sign" line styles using mapbox-ios (example :>>>>)

Question

I need a pointing line to tell someone the order of a line.

I added the dotted line style using MGLLineStyleLayer from mapbox-ios (example: - - - -) But I don't know if it supports the (>>>>) style, or the arrow (--->---), please tell me what to do.

Answer 1

You can create a line with an arrow by using the MGLineStyleLayer.linePattern property.

First, create a UIImage with the pattern that you would like to use (in this case, a line with an arrow). Then add that image to your style using [MGLStyle setImage:forName]. That image can then be used for the line pattern.

    func mapView(_ mapView: MGLMapView, didFinishLoading style: MGLStyle) {
        if let image = UIImage(named: "arrow.png") {
            style.setImage(image, forName: "arrow")
            let source = MGLShapeSource(identifier: "polyline", shape: shapeFromGeoJSON, options: nil)
            style.addSource(source)

            let layer = MGLLineStyleLayer(identifier: "polyline", source: source)
            layer.linePattern = NSExpression(forConstantValue: "arrow")
            layer.lineWidth = NSExpression(forConstantValue: 10)
            style.addLayer(layer)
        }
    }