苹果手表上画圈的外观不够光滑。 我怎样才能做得更好？

Question

. Answers to this question are eligible for a +50 reputation bounty. BCI wants to to this question.

One approach I tried is the following:

let circle = Circle.init()
let path = circle.path(in: kServiceRightFrame)
let serviceRightPath = UIBezierPath.init(cgPath: path.cgPath)
serviceRightPath.lineWidth = 2.0
serviceRightPath.fill()
serviceRightPath.stroke()

I played around with flatness too, but that did not get the job done either. How can a smoother looking circle be drawn programmatically?

EDIT:A more extensive view of my code:

 UIGraphicsBeginImageContext(kWatchInterfaceSize)
 let context = UIGraphicsGetCurrentContext()

 //draw service path
 kSBScoreLabelFontColor.setStroke()
 kSBServiceBallColor.setFill()
 ---> code from above
    
 // Convert to UIImage
 let cgimage = context!.makeImage()
    
 //create scoreboardimage
 let scoreBoardImage = UIImage(cgImage: cgimage!)
    
  // End the graphics context'
  UIGraphicsEndImageContext() 

Answer 1

George put me on the right track. It was a scaling issue. The code that I changed was the following:

//Replaced this
//UIGraphicsBeginImageContext(kWatchInterfaceSize) 
//with this
UIGraphicsBeginImageContextWithOptions(kWatchInterfaceSize, 
false, 4.0)

That fixed it. Now the circle looks a lot smoother in appearance.