AnyInsettableShape

AnyInsettableShape.swift

/// A type-erased shape that is able to inset itself to produce another shape.
/// 
/// See: [AnyShape](https://developer.apple.com/documentation/swiftui/anyshape), [InsettableShape](https://developer.apple.com/documentation/swiftui/insettableshape)
struct AnyInsettableShape: InsettableShape {

    private let _sizeThatFits: (ProposedViewSize) -> CGSize
    private let _path: (CGRect) -> Path
    private let _inset: (CGFloat) -> AnyInsettableShape

    init<S>(_ shape: S) where S : InsettableShape {
        _sizeThatFits = shape.sizeThatFits
        _path = shape.path
        _inset = { AnyInsettableShape(shape.inset(by: $0)) }
    }

    func sizeThatFits(_ proposal: ProposedViewSize) -> CGSize {
        _sizeThatFits(proposal)
    }

    func path(in rect: CGRect) -> Path {
        _path(rect)
    }

    func inset(by amount: CGFloat) -> some InsettableShape {
        _inset(amount)
    }
}