具有相同开始和结束角度的Swift 3.0绘制圆形结果符合直线

I've written following code to draw a rect with a whole in it:

我写了下面的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)

The problem here is this line:

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)

Printing out the description of the path: UIBezierPath: 0x6000000b35c0; MoveTo {-5, -5}, LineTo {380, -5}, LineTo {380, 672}, LineTo {-5, 672}, Close, MoveTo {312.5, 333.5}, LineTo {312.5, 333.49999999999994}, Close

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

As you can see, the last two entries are lineTo and close, which gives me not the expected result (a full circle), I'll get nothing because the line is too short between 333.5 and 333.4999999.

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。

This problem occurs since switching to Swift 3, in Objective-C this wasn't a problem.

自从切换到Swift 3后，在Objective-C中出现此问题，这不是问题。

Changing the end angle to 1.9 * Double.pi will also work, no idea why. But the full circle should have 2 * Double.pi.

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

Any idea or is it a Swift 3 bug?

任何想法或它是一个Swift 3错误？

1 个解决方案

#1

Try like this:

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