具有相同开始和结束角度的Swift 3.0绘制圆形结果一致

Question

我已经编写了以下代码来绘制一个带有整数的矩形：

fileprivate let strokeWidth: CGFloat = 5

let shapeLayer = CAShapeLayer()
shapeLayer.strokeColor = UIColor.white.cgColor
shapeLayer.lineWidth = strokeWidth
shapeLayer.fillColor = UIColor(white: 0.5, alpha: 0.9).cgColor

let p = UIBezierPath(rect: bounds.insetBy(dx: -strokeWidth, dy: -strokeWidth))
let radius = bounds.size.width / 3
p.move(to: CGPoint(x: bounds.midX + radius, y: bounds.midY))
p.addArc(withCenter: CGPoint(x: bounds.midX, y: bounds.midY), radius: radius, startAngle: 0, endAngle: CGFloat(2 * Double.pi), clockwise: false)
p.close()
shapeLayer.path = p.cgPath

layer.addSublayer(shapeLayer)

这里的问题是这一行：

p.addArc(withCenter: CGPoint(x: bounds.midX, y: bounds.midY), radius: radius, startAngle: 0, endAngle: CGFloat(2 * Double.pi), clockwise: false)

打印出路径描述： UIBezierPath：0x6000000b35c0; MoveTo {-5，-5}，LineTo {380，-5}，LineTo {380,672}，LineTo {-5,672}，关闭，MoveTo {312.5,333.5}，LineTo {312.5,333.49999999999994}，关闭< / p>

正如你所看到的，最后两个条目是lineTo和close，这给了我不是预期的结果（一个完整的圆圈），我什么也得不到，因为333.5和333.4999999之间的线太短了。

自从在Objective-C中切换到Swift 3后出现此问题，这不是一个问题。

将结束角度更改为1.9 * Double.pi也可以使用，不知道为什么。但整个圆圈应该有2 * Double.pi。

任何想法或者它是一个Swift 3错误？

Answer 1

试试这样：

let bounds = UIScreen.main.bounds
let strokeWidth: CGFloat = 5
let shapeLayer = CAShapeLayer()
shapeLayer.strokeColor = UIColor.white.cgColor
shapeLayer.lineWidth = strokeWidth
shapeLayer.fillColor = UIColor(white: 0.5, alpha: 0.9).cgColor
let p = UIBezierPath(rect: bounds.insetBy(dx: -strokeWidth, dy: -strokeWidth))
let radius = bounds.size.width / 3
p.move(to: CGPoint(x: bounds.midX + radius, y: bounds.midY))
p.addArc(withCenter: CGPoint(x: bounds.midX, y: bounds.midY), radius: radius, startAngle: 2 * .pi, endAngle: 0, clockwise: false)
p.close()
shapeLayer.fillColor = UIColor.red.cgColor
shapeLayer.strokeColor = UIColor.black.cgColor
shapeLayer.lineWidth = 5
shapeLayer.path = p.cgPath
let view = UIView(frame: bounds)
view.backgroundColor = .yellow
view.layer.addSublayer(shapeLayer)

view