How to set a custom view's intrinsic content size in Swift?

Question

Background

I am making a vertical label to use with traditional Mongolian script. Before I was just rotating a UILabel but there were s

Answer 1

Example of a "view with intrinsic height" ...

@IBDesignable class HView: UIView {

    @IBInspectable var height: CGFloat = 100.0

    override var intrinsicContentSize: CGSize {
        return CGSize(width: 99, height: height)
        // if using in, say, a vertical stack view, the width is ignored
    }

    override func prepareForInterfaceBuilder() {
         invalidateIntrinsicContentSize()
    }
}

which you can set as an inspectable

Since it has an intrinsic height, it can (for example) be immediately inserted in a stack view in code:

stack?.insertArrangedSubview(HView(), at: 3)

In contrast, if it was a normal view with no intrinsic height, you'd have to add a height anchor or it would crash:

let v:UIView = HView()
v.heightAnchor.constraint(equalToConstant: 100).isActive = true
stack?.insertArrangedSubview(v, at: 3)

Note that in ...

the important special case of a stack view:

• you set only ONE anchor (for vertical stack view, the height; for horizontal the width)

so, setting the intrinsic height works perfectly, since:

• the intrinsic height indeed means that the height anchor specifically will be set automatically if needed.

Remembering that in all normal cases of a subview, many other anchors are needed.