ios - UIImage在UIBezierPath的最后一点

我想在UIBezierPath的最后一点添加一个UIImage，如下图所示：
Circle Path
代码：

let consume = 0.25
let x = self.frame.size.width / 2.0
let y = self.frame.size.height / 2.0
let radius = (frame.size.width - 10) / 2.0
let startAngle: CGFloat = CGFloat(M_PI * (-1/2))
let endAngle = CGFloat(M_PI * 2 - M_PI/2 * consume)
let circlePath = UIBezierPath(arcCenter: CGPoint(x: x, y: y), radius: radius, startAngle: startAngle, endAngle: endAngle, clockwise: false)

circleLayer = CAShapeLayer()
circleLayer.path = circlePath.cgPath
circleLayer.fillColor = UIColor.clear.cgColor
circleLayer.strokeColor = UIColor.red.cgColor
circleLayer.lineWidth = 8.0;

let image = UIImage(named: "myCoolImage")
let imageView = UIImageView(image: image)
// coordX and coordY must be at last point of UIBezierPath
imageView.frame = CGRect(x: coordX, y: coordY, width: 20.0, height: 20.0)
self.addSubview(imageView)

我试过以下方法：

let coordX: CGFloat = cos(endAngle) * radius
let coordY: CGFloat = sin(endAngle) * radius

结果：
Positive coordX and coordY
主要的问题是如何计算坐标和坐标。

最佳答案

为了得到一个实际的、充分充实的答案，这里基本上是你所需要的。

let consume = 0.25
let x = self.frame.size.width / 2.0
let y = self.frame.size.height / 2.0
let radius = (frame.size.width - 10) / 2.0
let startAngle: CGFloat = CGFloat(M_PI * (-1/2))
let endAngle = CGFloat(M_PI * 2 - M_PI/2 * consume)
let circlePath = UIBezierPath(arcCenter: CGPoint(x: x, y: y), radius: radius, startAngle: startAngle, endAngle: endAngle, clockwise: false)

circleLayer = CAShapeLayer()
circleLayer.path = circlePath.cgPath
circleLayer.fillColor = UIColor.clear.cgColor
circleLayer.strokeColor = UIColor.red.cgColor
circleLayer.lineWidth = 8.0;

let imageSize = 20.0
// Center + cos/sin(angle) * radius, then subtract half
// the image size so it will be centered on the line
let coordX: CGFloat = x + (cos(endAngle) * radius) - (imageSize / 2.0)
let coordY: CGFloat = y - (sin(endAngle) * radius) - (imageSize / 2.0)

let image = UIImage(named: "myCoolImage")
let imageView = UIImageView(image: image)
// coordX and coordY must be at last point of UIBezierPath
imageView.frame = CGRect(x: coordX, y: coordY, width: imageSize, height: imageSize)
self.addSubview(imageView)