聊天小三角

绘制聊天小三角

1.先创建一个UIView， 并添加在父视图上

let blankView = UIView(frame: CGRectMake(100, 100, 100, 100))

blankView.backgroundColor = UIColor.greenColor()

blankView.layer.mask = test(blankView)

self.view.addSubview(blankView)

2.创建一个方法

//设置小三角

func test(showView: UIView) -> CAShapeLayer {

let viewWidth = CGFloat(CGRectGetWidth(showView.frame))

let viewHeight = CGFloat(CGRectGetHeight(showView.frame))

//所占的宽度,整个view所占的宽度不会变,已经被制定,所以这个宽度会占用整个view的宽度,

let rightSpace: CGFloat = 10

//距离顶部的距离

let topSpace: CGFloat = 30

let point1 = CGPointMake(0, 0)

let point2 = CGPointMake(viewWidth - rightSpace, 0)

let point3 = CGPointMake(viewWidth - rightSpace, topSpace)

let point4 = CGPointMake(viewWidth, topSpace)

let point5 = CGPointMake(viewWidth - rightSpace, topSpace + 10)

let point6 = CGPointMake(viewWidth - rightSpace, viewHeight)

let point7 = CGPointMake(0, viewHeight)

let path = UIBezierPath()

path.moveToPoint(point1)

path.addLineToPoint(point2)

path.addLineToPoint(point3)

path.addLineToPoint(point4)

path.addLineToPoint(point5)

path.addLineToPoint(point6)

path.addLineToPoint(point7)

let layer = CAShapeLayer()

layer.path = path.CGPath

return layer

}