Drawing Smooth Curves - Methods Needed

Question

How do you smooth a set of points in an iOS drawing app WHILE MOVING? I have tried UIBezierpaths but all I get are jagged ends where they intersect, when I just shift the po

Answer 1

Here is the code in Swift 4/5

func quadCurvedPathWithPoint(points: [CGPoint] ) -> UIBezierPath {
    let path = UIBezierPath()
    if points.count > 1 {
        var prevPoint:CGPoint?
        for (index, point) in points.enumerated() {
            if index == 0 {
                path.move(to: point)
            } else {
                if index == 1 {
                    path.addLine(to: point)
                }
                if prevPoint != nil {
                    let midPoint = self.midPointForPoints(from: prevPoint!, to: point)
                    path.addQuadCurve(to: midPoint, controlPoint: controlPointForPoints(from: midPoint, to: prevPoint!))
                    path.addQuadCurve(to: point, controlPoint: controlPointForPoints(from: midPoint, to: point))
                }
            }
            prevPoint = point
        }
    }
    return path
}

func midPointForPoints(from p1:CGPoint, to p2: CGPoint) -> CGPoint {
    return CGPoint(x: (p1.x + p2.x) / 2, y: (p1.y + p2.y) / 2)
}

func controlPointForPoints(from p1:CGPoint,to p2:CGPoint) -> CGPoint {
    var controlPoint = midPointForPoints(from:p1, to: p2)
    let  diffY = abs(p2.y - controlPoint.y)
    if p1.y < p2.y {
        controlPoint.y = controlPoint.y + diffY
    } else if ( p1.y > p2.y ) {
        controlPoint.y = controlPoint.y - diffY
    }
    return controlPoint
}