How to draw an arc on Google Maps in iOS?

Question

How to draw an arc between two coordinate points in Google Maps like in this image and same like facebook post in iOS ?

Answer 1

I used Bezier quadratic equation to draw curved lines. You can have a look on to the implementation. Here is the sample code.

func bezierPath(from startLocation: CLLocationCoordinate2D, to endLocation: CLLocationCoordinate2D) -> GMSMutablePath {

        let distance = GMSGeometryDistance(startLocation, endLocation)
        let midPoint = GMSGeometryInterpolate(startLocation, endLocation, 0.5)

        let midToStartLocHeading = GMSGeometryHeading(midPoint, startLocation)

        let controlPointAngle = 360.0 - (90.0 - midToStartLocHeading)
        let controlPoint = GMSGeometryOffset(midPoint, distance / 2.0 , controlPointAngle)
        
        let path = GMSMutablePath()
        
        let stepper = 0.05
        let range = stride(from: 0.0, through: 1.0, by: stepper)// t = [0,1]
        
        func calculatePoint(when t: Double) -> CLLocationCoordinate2D {
            let t1 = (1.0 - t)
            let latitude = t1 * t1 * startLocation.latitude + 2 * t1 * t * controlPoint.latitude + t * t * endLocation.latitude
            let longitude = t1 * t1 * startLocation.longitude + 2 * t1 * t * controlPoint.longitude + t * t * endLocation.longitude
            let point = CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
            return point
        }
        
        range.map { calculatePoint(when: $0) }.forEach { path.add($0) }
        return path
 }