How to set objects around circle correctly on UIView - ios

Question

I've write some code to place objects around circle that locate on center of the Custom view, but it not perfectly around the circle. I don't know where of the code is wrong.
Here is the code:
func createObjectsAroundCircle() {
let center = CGPointMake(bounds.width/2 ,bounds.height/2)
let radius : CGFloat = 100
let count = 20
var angle = CGFloat(2 * M_PI)
let step = CGFloat(2 * M_PI) / CGFloat(count)
let circlePath = UIBezierPath(arcCenter: center, radius: radius, startAngle: CGFloat(0), endAngle:CGFloat(M_PI * 2), clockwise: true)
let shapeLayer = CAShapeLayer()
shapeLayer.path = circlePath.CGPath
shapeLayer.fillColor = UIColor.clearColor().CGColor
shapeLayer.strokeColor = UIColor.redColor().CGColor
shapeLayer.lineWidth = 3.0
self.layer.addSublayer(shapeLayer)
// set objects around circle
for var index = 0; index < count ; index++ {
let x = cos(angle) * radius + center.x
let y = sin(angle) * radius + center.y
let label = UILabel()
label.text = "\(index)"
label.frame.origin.x = x
label.frame.origin.y = y
label.font = UIFont(name: "Arial", size: 20)
label.textColor = UIColor.blackColor()
label.sizeToFit()
self.addSubview(label)
angle += step
}
}

Answer 1

Your code is working alright, just calculation logic is wrong. You should try to set label.center instead of label.frame.origin, or
let label = UILabel()
label.text = "\(index)"
label.font = UIFont(name: "Arial", size: 20)
label.textColor = UIColor.blackColor()
label.sizeToFit()
label.frame.origin.x = x - label.frame.midX
label.frame.origin.y = y - label.frame.midY
Remember to sizeToFit() before changing frame or setting center of the label. Good Luck!

Answer 2

Swift 5
For convenience purposes, both Masa S-AiYa question logic + Fahri Azimov answer have been combined:
let center = CGPoint(x: bounds.size.width/2, y: bounds.size.width/2)
let radius: CGFloat = 100
let count = 20
let pi = Double.pi
var angle = CGFloat(2 * pi)
let step = CGFloat(2 * pi) / CGFloat(count)
let circlePath = UIBezierPath(arcCenter: center, radius: radius, startAngle: CGFloat(0), endAngle:CGFloat(pi * 2), clockwise: true)
let shapeLayer = CAShapeLayer()
shapeLayer.path = circlePath.cgPath
shapeLayer.fillColor = UIColor.clear.cgColor
shapeLayer.strokeColor = UIColor.red.cgColor
shapeLayer.lineWidth = 3.0
layer.addSublayer(shapeLayer)
let font = UIFont(name: "Arial", size: 20)
// Set objects around the circle
for index in 0..<count {
let label = UILabel()
label.text = "\(index)"
label.font = font
label.textColor = .black
// Remember to call 'sizeToFit()' before changing 'frame' or setting 'center' of the label!
label.sizeToFit()
// Position
let x = cos(angle) * radius + center.x
let y = sin(angle) * radius + center.y
let midX = label.frame.x + label.frame.width / 2
let mixY = label.frame.y + label.frame.height / 2
label.frame.origin.x = x - midX
label.frame.origin.y = y - mixY
addSubview(label)
angle += step
}