使用由CAShapeLayer支持的UIView形成三角形

Question

从教程：http://swiftiostutorials.com/tutorial-draw-nice-triangle-view-border-cashapelayer/，我设法创建了一个三角形，如：

class Triangle: UIView {
    override func drawRect(rect: CGRect) {
        let mask = CAShapeLayer()
        mask.frame = self.layer.bounds

        let width = self.layer.frame.size.width
        let height = self.layer.frame.size.height

        let path = CGPathCreateMutable()

        CGPathMoveToPoint(path, nil, 0, 0)
        CGPathAddLineToPoint(path, nil, width, 0)
        CGPathAddLineToPoint(path, nil, width, height)
        CGPathAddLineToPoint(path, nil, width/2, height)
        CGPathAddLineToPoint(path, nil, width, height)


        mask.path = path
        self.layer.mask = mask
    }
}

但我想要实现的是一个三角形：

如何做到这一点？

Answer 1

请改用此路径：

CGPathMoveToPoint(path, nil, 0, 0)
CGPathAddLineToPoint(path, nil, width, 0)
CGPathAddLineToPoint(path, nil, width/2, height)
CGPathAddLineToPoint(path, nil, 0, 0)

全班：

class Triangle: UIView {
    override func drawRect(rect: CGRect) {
        let mask = CAShapeLayer()
        mask.frame = self.layer.bounds

        let width = self.layer.frame.size.width
        let height = self.layer.frame.size.height

        let path = CGPathCreateMutable()

        CGPathMoveToPoint(path, nil, 0, 0)
        CGPathAddLineToPoint(path, nil, width, 0)
        CGPathAddLineToPoint(path, nil, width/2, height)
        CGPathAddLineToPoint(path, nil, 0, 0)

        mask.path = path
        self.layer.mask = mask
    }
}