dimensions(in:)
Asks the subview for its dimensions and alignment guides.
Declaration
func dimensions(in proposal: ProposedViewSize) -> ViewDimensionsParameters
- 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.
Return Value
A ViewDimensions instance that includes a height and width, as well as a set of alignment guides.
Discussion
Call this method to ask a subview of a custom Layout type about its size and alignment properties. You can call it from your implementation of any of that protocol’s methods, like placeSubviews(in:proposal:subviews:cache:) or sizeThatFits(proposal:subviews:cache:), to get information for your layout calculations.
When you call this method, you propose a size using the proposal parameter. The subview can choose its own size, but might take the proposal into account. You can call this method more than once with different proposals to find out if the view is flexible. For example, you can propose:
zero to get the subview’s minimum size.
infinity to get the subview’s maximum size.
unspecified to get the subview’s ideal size.
If you need only the view’s height and width, you can use the sizeThatFits(_:) method instead.