place(at:anchor:proposal:)

Declaration

func place(at position: CGPoint, anchor: UnitPoint = .topLeading, proposal: ProposedViewSize)

Parameters

• position:

  The place where the anchor of the subview should appear in its container view, relative to container’s bounds.

• anchor:

  The unit point on the subview that appears at position. You can use a built-in point, like Center, or you can create a custom Unitpoint.

• proposal:

  A proposed size for the subview. In SwiftUI, views choose their own size, but can take a size proposal from their parent view into account when doing so.

Discussion

Call this method from your implementation of the Layout protocol’s placeSubviews(in:proposal:subviews:cache:) method for each subview arranged by the layout. Provide a position within the container’s bounds where the subview should appear, and an anchor that indicates which part of the subview appears at that point.

Include a proposed size that the subview can take into account when sizing itself. To learn the subview’s size for a given proposal before calling this method, you can call the dimensions(in:) or sizeThatFits(_:) method on the subview with the same proposal. That enables you to know subview sizes before committing to subview positions.

If you call this method more than once for a subview, the last call takes precedence. If you don’t call this method for a subview, the subview appears at the center of its layout container and uses the layout container’s size proposal.