Ios 如何使用swift 3在视图中显示栅格

我在视图中得到了网格，但是线条超出了我附加的图像的框架，我得到了一个输出，如何解决这个问题

    path = UIBezierPath()
    path.lineWidth = 5.0

    for index in 1...Int(gridWidthMultiple) - 1
    {
        let start = CGPoint(x: CGFloat(index) * gridWidth, y: 0)
        let end = CGPoint(x: CGFloat(index) * gridWidth, y: bounds.height)
        path.move(to: start)
        path.addLine(to: end)
    }
    let numberOfRows: Int = Int(self.frame.size.height)/Int(gridWidth);

    for index in 1...numberOfRows {
        let start = CGPoint(x: 0.0, y: gridWidth * CGFloat(index))
        let end = CGPoint(x: self.frame.size.width, y: start.y)
        path.move(to: start)
        path.addLine(to: end)
    }
    self.setNeedsDisplay()

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是否已尝试将栅格视图的clipsToBounds属性设置为true？

视图层次结构是什么样的？