Add lines to the circle at a given angle in Core Graphics Swift - swift

Question

I create this circle view like this:
override func draw(_ rect: CGRect) {
super.draw(rect)
if let context = UIGraphicsGetCurrentContext()
{
let width = fmin(self.frame.size.width, self.frame.size.height)
let offset_x = abs(width - self.frame.size.width)/2
let offset_y = abs(width - self.frame.size.height)/2
let padding = CGFloat(0.5)
let radius_size = (width/2) - (padding*2)
let circle_width = radius_size/4
context.setStrokeColor(UIColor.black.cgColor)
// Draw a circle
for i in 0 ..< 4
{
let offset = CGFloat(i) * circle_width
context.strokeEllipse(in:
CGRect(
x: padding + offset + offset_x,
y: padding + offset + offset_y,
width: (radius_size - offset)*2,
height: (radius_size - offset)*2))
}
context.strokePath()
}
}
How can I create a line to the circle center, if I have an array, of angles for the most top circle? And how can I do the same, for the middle circle?
For example, I have an array, with the given angles in degrees: [87.0, 112.0, 150.0]

Answer 1

Here's a function drawLine that draws a line from a center point at an angle with a specific radius. To change which circle the line reaches, just change the radius:
override func draw(_ rect: CGRect) {
super.draw(rect)
if let context = UIGraphicsGetCurrentContext()
{
let width = fmin(self.frame.size.width, self.frame.size.height)
let offset_x = abs(width - self.frame.size.width)/2
let offset_y = abs(width - self.frame.size.height)/2
let padding = CGFloat(0.5)
let radius_size = (width/2) - (padding*2)
let circle_width = radius_size/4
context.setStrokeColor(UIColor.black.cgColor)
// Draw a circle
for i in 0 ..< 4
{
let offset = CGFloat(i) * circle_width
context.strokeEllipse(in:
CGRect(
x: padding + offset + offset_x,
y: padding + offset + offset_y,
width: (radius_size - offset)*2,
height: (radius_size - offset)*2))
}
let angles: [CGFloat] = [87.0, 112.0, 150]
let angles2: [CGFloat] = [210.0, 250.0, 330.0]
let center = CGPoint(x: width/2 + offset_x, y: width/2 + offset_y)
for angle in angles {
drawLine(context: context, center: center, radius: radius_size, angle: angle)
}
for angle in angles2 {
drawLine(context: context, center: center, radius: radius_size * 3 / 4, angle: angle)
}
context.strokePath()
}
}
func drawLine(context: CGContext, center: CGPoint, radius: CGFloat, angle: CGFloat) {
context.move(to: center)
context.addLine(to: CGPoint(x: center.x + radius * cos(angle * .pi / 180), y: center.y - radius * sin(angle * .pi / 180)))
}