Draw Circle where user clicks with UIBezierPath - swift

Question

I am new to swift. I want to draw Circle on those pixels where user clicks.
Here is my code it is drawing circle but not at where I clicks....
I want to draw circle where user clicks....Like it is getting the coordinates where user clicks and printing them to console but I want to update the x and y arguments in ovalsandcircles() function.
Thanks in advance.
`import UIKit
class DemoView: UIView {
var startX :CGFloat = 0.0
var startY :CGFloat = 0.0
var path: UIBezierPath!
override init(frame: CGRect) {
super.init(frame: frame)
self.backgroundColor = UIColor.darkGray
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
}
override func draw(_ rect: CGRect) {
// Specify the fill color and apply it to the path.
ovalsAndCircles()
UIColor.orange.setFill()
path.fill()
Specify a border (stroke) color.
UIColor.purple.setStroke()
path.stroke()
}
func ovalsAndCircles () {
self.path = UIBezierPath(ovalIn: CGRect(x: startX,
y: startY,
width: 200,
height: 200))
}
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let point = touches.first!.location(in: self)
startX = point.x
startY = point.y
print(startY)
print(startX)
}
}
`

Answer 1

(1) Add a UIView control through Interface Builder.
(2) Set the class name of that UIView control to DemoView.
(3) Create a subclass of UIView as DemoView as follows.
import UIKit
class DemoView: UIView {
let fillColor = UIColor.green
let strokeColor = UIColor.black
let radius: CGFloat = 100.0
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
let touch = event?.allTouches?.first
if let touchPoint = touch?.location(in: self) {
drawCircle(point: touchPoint)
}
}
func drawCircle(point: CGPoint) {
if let subLayers = self.layer.sublayers {
for subLayer in subLayers {
subLayer.removeFromSuperlayer()
}
}
let circlePath = UIBezierPath(arcCenter: point, radius: radius, startAngle: CGFloat(0), endAngle: CGFloat(Double.pi * 2.0), clockwise: true)
let shapeLayer = CAShapeLayer()
shapeLayer.path = circlePath.cgPath
shapeLayer.fillColor = fillColor.cgColor
shapeLayer.strokeColor = strokeColor.cgColor
self.layer.addSublayer(shapeLayer)
}
}

Answer 2

First look at the Coordinate System in iOS: https://developer.apple.com/library/archive/documentation/General/Conceptual/Devpedia-CocoaApp/CoordinateSystem.html
The CGRect has a origin property of type CGPoint. Maybe it helps to set the origin of your rect in your draw function:
let rect: CGRect = ....
rect.origin = CGPoint(x:0.5, y:0.5) //Set the origin to the middle of the rect

Answer 3

You call the touchesBegan Method to set the points where it should be drawn. But when the user moves over the screen it wont be recognized. Use touchesEnded Method instead