我有一个UIView的子类，其中包含一堆使用CGPAth绘制的图形。我需要知道何时触摸触及这些路径之一，以及哪个路径。
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for t in touches {
for p in myDrawnPaths {
if(p.contains(t.location(in: self)) {
doStuffWith(p)
}
}
}
}
有时，这段代码会导致doStuffWith()在多条路径上执行，包括远离命中位置的路径。我做了一些检查，发现应该受到影响的路径确实有些奇怪：
override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
for t in touches {
for p in myDrawnPaths {
print(p.contains(t.location(in: self))) //true
print(p.boundingBox.contains(t.location(in: self))) //false!
}
}
}
嗯？边界框不应该包含整个路径，这意味着路径内的点是否一定在边界框内？
仅在此类测试中出现问题-当我使用CoreGraphics API绘制相同的CGPath并为其设置动画时，所有显示都是正确的。
更新
我试图在Playgrounds中通过简单的实验路径重现该问题，但是无法做到，所以我不得不从我的实际应用程序中提取这个问题。
(75.0, 264.0) is in
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我们看到，路径中的所有点的X坐标都在200 s之内，但是X坐标为75的点被计算在该路径之内。
如果我在路径上使用close命令，问题就消失了，但这带来了其他问题：
CGPath的contains在开放路径上如何工作，以及在哪里记录（如果有的话）？
这为什么会影响contains方法的结果，而不影响屏幕上显示的内容？例如，如果我告诉相应的CALayer用某种颜色填充，那么该颜色不会溢出超出其应有的范围。
答案 0 :(得分：1)
在操场上进行了实验后，我发现对于x值大于或等于CGRect.contains(:)的点，maxX方法返回false。或大于或等于maxY的的y值。
事实证明，CGRect的documentation表示类似的内容：
如果点的坐标位于矩形内或最小X或最小Y边上，则认为该点在矩形内。
我认为文档的措辞很差，因为最大X和最大Y边缘的交点不包括相同。
下面是证明这一点的代码：
let rect = CGRect(x: 0, y: 0, width: 200, height: 200)
rect.contains(CGPoint(x: 0, y: 0)) // true
rect.contains(CGPoint(x: rect.midX, y: 0)) // true
rect.contains(CGPoint(x: 0, y: rect.midY)) // true
rect.contains(CGPoint(x: 200, y: 200)) // false
rect.contains(CGPoint(x: 200, y: 0)) // false
rect.contains(CGPoint(x: 0, y: 200)) // false
rect.contains(CGPoint(x: 0, y: rect.maxY)) // false
rect.contains(CGPoint(x: rect.maxX, y: 0)) // false
rect.contains(CGPoint(x: rect.maxX, y: rect.maxY)) // false
rect.maxX // 200
rect.maxY // 200
此外，documentation指出boundingBox包含路径的所有点，包括贝塞尔曲线和二次曲线的控制点。您可能要改用boundingBoxOfPath。