Swift中的UIBezierPath：Path非常奇怪地被关闭了

Question

我正在使用Drawing class drawing straight lines instead of curved lines的扩展来插值u形图。不幸的是，这条道路以一种奇怪的方式被关闭了：

应该是什么样的：

它实际上是什么样的：

我的代码：

override func drawRect(rect: CGRect) {
    let points: [CGPoint] = [CGPoint(x: 78, y: 99), CGPoint(x: 78, y: 128), CGPoint(x: 78, y: 173), CGPoint(x: 84, y: 199), CGPoint(x: 95, y: 223), CGPoint(x: 112, y: 240), CGPoint(x: 136, y: 243), CGPoint(x: 170, y: 236), CGPoint(x: 203, y: 217), CGPoint(x: 227, y: 190), CGPoint(x: 240, y: 160), CGPoint(x: 241, y: 134), CGPoint(x: 241, y: 108), CGPoint(x: 240, y: 93), CGPoint(x: 239, y: 84), CGPoint(x: 237, y: 75), CGPoint(x: 78, y: 99), CGPoint(x: 78, y: 128), CGPoint(x: 78, y: 173), CGPoint(x: 84, y: 199), CGPoint(x: 95, y: 223), CGPoint(x: 112, y: 240), CGPoint(x: 136, y: 243), CGPoint(x: 170, y: 236), CGPoint(x: 203, y: 217), CGPoint(x: 227, y: 190), CGPoint(x: 240, y: 160), CGPoint(x: 241, y: 134), CGPoint(x: 241, y: 108), CGPoint(x: 240, y: 93), CGPoint(x: 239, y: 84), CGPoint(x: 237, y: 75), CGPoint(x: 78, y: 99), CGPoint(x: 78, y: 128), CGPoint(x: 78, y: 173), CGPoint(x: 84, y: 199), CGPoint(x: 95, y: 223), CGPoint(x: 112, y: 240), CGPoint(x: 136, y: 243), CGPoint(x: 170, y: 236), CGPoint(x: 203, y: 217), CGPoint(x: 227, y: 190), CGPoint(x: 240, y: 160), CGPoint(x: 241, y: 134), CGPoint(x: 241, y: 108), CGPoint(x: 240, y: 93), CGPoint(x: 239, y: 84), CGPoint(x: 237, y: 75)]

    let path = UIBezierPath(hermiteInterpolatedPoints: points, closed: false)

    if let path = path {
        UIColor.blueColor().set()
        path.lineWidth = 5.0
        path.stroke()
    } 
}

当数组缩短为：

let points: [CGPoint] = [CGPoint(x: 78, y: 99), CGPoint(x: 78, y: 128), CGPoint(x: 78, y: 173), CGPoint(x: 84, y: 199), CGPoint(x: 95, y: 223), CGPoint(x: 112, y: 240), CGPoint(x: 136, y: 243), CGPoint(x: 170, y: 236), CGPoint(x: 203, y: 217), CGPoint(x: 227, y: 190), CGPoint(x: 240, y: 160), CGPoint(x: 241, y: 134), CGPoint(x: 241, y: 108)]

看起来像这样：

Answer 1

你的点数是相同的16点重复三次。

let points: [CGPoint] = [
    CGPoint(x: 78, y: 99), CGPoint(x: 78, y: 128), CGPoint(x: 78, y: 173), CGPoint(x: 84, y: 199), CGPoint(x: 95, y: 223), CGPoint(x: 112, y: 240), CGPoint(x: 136, y: 243), CGPoint(x: 170, y: 236), CGPoint(x: 203, y: 217), CGPoint(x: 227, y: 190), CGPoint(x: 240, y: 160), CGPoint(x: 241, y: 134), CGPoint(x: 241, y: 108), CGPoint(x: 240, y: 93), CGPoint(x: 239, y: 84), CGPoint(x: 237, y: 75),
    CGPoint(x: 78, y: 99), CGPoint(x: 78, y: 128), CGPoint(x: 78, y: 173), CGPoint(x: 84, y: 199), CGPoint(x: 95, y: 223), CGPoint(x: 112, y: 240), CGPoint(x: 136, y: 243), CGPoint(x: 170, y: 236), CGPoint(x: 203, y: 217), CGPoint(x: 227, y: 190), CGPoint(x: 240, y: 160), CGPoint(x: 241, y: 134), CGPoint(x: 241, y: 108), CGPoint(x: 240, y: 93), CGPoint(x: 239, y: 84), CGPoint(x: 237, y: 75),
    CGPoint(x: 78, y: 99), CGPoint(x: 78, y: 128), CGPoint(x: 78, y: 173), CGPoint(x: 84, y: 199), CGPoint(x: 95, y: 223), CGPoint(x: 112, y: 240), CGPoint(x: 136, y: 243), CGPoint(x: 170, y: 236), CGPoint(x: 203, y: 217), CGPoint(x: 227, y: 190), CGPoint(x: 240, y: 160), CGPoint(x: 241, y: 134), CGPoint(x: 241, y: 108), CGPoint(x: 240, y: 93), CGPoint(x: 239, y: 84), CGPoint(x: 237, y: 75)
]

你从最后一点CGPoint(x: 237, y: 75)跳回到开始点CGPoint(x: 78, y: 99)，（你正在做两次），这就是关闭路径。

该数组的路径是正确的，它重复三次相同的点序列。