Get N number of CGPoints around a circle on UIView - ios

Question

I got a center CGPoint and radius Float, I need to get N number of points surrounding the circle, for example in below image how to get the 12 points corresponding red dots.
This is my incomplete function:
func getCirclePoints(centerPoint point: CGPoint, and radius: CGFloat, n: Int) [CGPoint] {
let result: [CGPoint] = stride(from: 0.0, to: 360.0, by: CGFloat(360 / n)).map {
let bearing = $0 * .pi / 180
// NO IDEA WHERE TO MOVE FURTHER
}
return result
}
getCirclePoints(centerPoint: CGPoint(x: 160, y: 240), radius: 120.0, n: 12)

Answer 1

You were almost there!
func getCirclePoints(centerPoint point: CGPoint, radius: CGFloat, n: Int)->[CGPoint] {
let result: [CGPoint] = stride(from: 0.0, to: 360.0, by: Double(360 / n)).map {
let bearing = CGFloat($0) * .pi / 180
let x = point.x + radius * cos(bearing)
let y = point.y + radius * sin(bearing)
return CGPoint(x: x, y: y)
}
return result
}
let points = getCirclePoints(centerPoint: CGPoint(x: 160, y: 240), radius: 120.0, n: 12)
I didn't think and was very clear as an argument name so I've removed this.

Answer 2

Use radians instead of degrees. They are needed inside trigonometric functions
func getCirclePoints(centerPoint point: CGPoint, and radius: CGFloat, n: Int) -> [CGPoint] {
return Array(repeating: 0, count: n).enumerated().map { offset, element in
let cgFloatIndex = CGFloat(offset)
let radiansStep = CGFloat.pi * CGFloat(2.0) / CGFloat(n)
let radians = radiansStep * cgFloatIndex
let x = cos(radians) * radius + point.x
let y = sin(radians) * radius + point.y
return CGPoint(x: x, y: y)
}
}
func getCirclePoints1(centerPoint point: CGPoint, and radius: CGFloat, n: Int) -> [CGPoint] {
var resultPoints: [CGPoint] = []
let radianStep = CGFloat.pi * CGFloat(2.0) / CGFloat(n)
for radians in stride(from: CGFloat(0.0), to: CGFloat.pi * CGFloat(2.0), by: radianStep) {
let x = cos(radians) * radius + point.x
let y = sin(radians) * radius + point.y
resultPoints.append(CGPoint(x: x, y: y))
}
return resultPoints
}
func getCirclePoints2(centerPoint point: CGPoint, and radius: CGFloat, n: Int) -> [CGPoint] {
let radianStep = CGFloat.pi * CGFloat(2.0) / CGFloat(n)
return stride(from: CGFloat(0.0), to: CGFloat.pi * CGFloat(2.0), by: radianStep).map { element in
let cgFloatIndex = CGFloat(element)
let radiansStep = CGFloat.pi * CGFloat(2.0) / CGFloat(n)
let radians = radiansStep * cgFloatIndex
let x = cos(radians) * radius + point.x
let y = sin(radians) * radius + point.y
return CGPoint(x: x, y: y)
}
}
getCirclePoints(centerPoint: CGPoint(x: 160, y: 240), and: 120.0, n: 12)

Answer 3

For having a draw reference
import UIKit
let numOfItems = 10
class customView : UIView {
// Only override draw() if you perform custom drawing.
// An empty implementation adversely affects performance during animation.
override func draw(_ rect: CGRect) {
for i in 0...numOfItems
{
let angle = 360/CGFloat(numOfItems) * CGFloat(i) * .pi / 180
let rad = self.bounds.size.width/2 - 10
let x = bounds.midX + cos(angle) * rad
let y = bounds.midY + sin(angle) * rad
let circlePath = UIBezierPath(
arcCenter: CGPoint(x:x,y:y),
radius:10,
startAngle:0,
endAngle:360,
clockwise: true)
let shapeLayer = CAShapeLayer()
shapeLayer.fillColor = UIColor.red.cgColor
shapeLayer.strokeColor = UIColor.blue.cgColor
shapeLayer.lineWidth = 3
shapeLayer.path = circlePath.cgPath
layer.addSublayer(shapeLayer)
}
}
}