如何在iOS的Google地图上绘制圆弧？

Question

如何在Google Maps中的两个坐标点之间绘制圆弧（如此图像）和iOS中的facebook post相同？

Answer 1

在使用以下功能之前，请不要忘记导入GoogleMaps 点数：xomena

func drawArcPolyline(startLocation: CLLocationCoordinate2D?, endLocation: CLLocationCoordinate2D?) {
    if let _ = startLocation, let _ = endLocation {
        //swap the startLocation & endLocation if you want to reverse the direction of polyline arc formed.
        let mapView = GMSMapView()
        let path = GMSMutablePath()
        path.add(startLocation!)
        path.add(endLocation!)
        // Curve Line
        let k: Double = 0.2 //try between 0.5 to 0.2 for better results that suits you
        let d = GMSGeometryDistance(startLocation!, endLocation!)
        let h = GMSGeometryHeading(startLocation!, endLocation!)
        //Midpoint position
        let p = GMSGeometryOffset(startLocation!, d * 0.5, h)
        //Apply some mathematics to calculate position of the circle center
        let x = (1-k*k)*d*0.5/(2*k);
        let r = (1+k*k)*d*0.5/(2*k);
        let c = GMSGeometryOffset(p, x, h + 90.0)
        //Polyline options
        //Calculate heading between circle center and two points
        let h1 =  GMSGeometryHeading(c, startLocation!)
        let h2 = GMSGeometryHeading(c, endLocation!)
        //Calculate positions of points on circle border and add them to polyline options
        let numpoints = 100.0
        let step = ((h2 - h1) / Double(numpoints))
        for i in stride(from: 0.0, to: numpoints, by: 1) {
            let pi = GMSGeometryOffset(c, r, h1 + i * step)
            path.add(pi)
        }
        //Draw polyline
        let polyline = GMSPolyline(path: path)
        polyline.map = mapView // Assign GMSMapView as map
        polyline.strokeWidth = 3.0
        let styles = [GMSStrokeStyle.solidColor(UIColor.black), GMSStrokeStyle.solidColor(UIColor.clear)]
        let lengths = [20, 20] // Play with this for dotted line
        polyline.spans = GMSStyleSpans(polyline.path!, styles, lengths as [NSNumber], .rhumb)

        let bounds = GMSCoordinateBounds(coordinate: startLocation!, coordinate: endLocation!)
        let insets = UIEdgeInsets(top: 20, left: 20, bottom: 20, right: 20)
        let camera = mapView.camera(for: bounds, insets: insets)!
        mapView.animate(to: camera)
    }
}