ios - UIImageView 添加了layer mask，想要给mask增加inset

Question

最近在做拼图，参考的linecamera， 怎么设置inset呢。

追加问题： 现在出现一个新的问题， 我要改变北京色为图片， 这时候就有问题了，不能是layer压在上面了， 需要用这个layer去做整体的mask，但是，layer的stroke color 设置为透明，fill 黑色，mask之后显示出来的部分只有一半。 因为fill会填充stroke的一半。。。。

Answer 1

Actually, I made this problem complicated myself, and it can be solved by adding a borderLayer.
First subtract the borderwidth from the size of the canvas, construct the path based on the Size, get the borderLayer, and add it.
It’s actually very simple, but there are a lot of things associated with it. There are shapes, editpoints, and other elements on the canvas, and their positions need to be recalculated based on the borderWidth.

Answer 2

Use all gray as the background color, cover it with red and green, and set the view.layer.mask twice to meet the requirements of CAShapeLayer(). Isn’t it quite convenient?