distance(to:along:)

Declaration

func distance(to next: ViewSpacing, along axis: Axis) -> CGFloat

Parameters

• next:

  The spacing preferences instance of the adjacent view.

• axis:

  The axis that the two views align on.

Return Value

A floating point value that represents the smallest distance in points between two views that satisfies the spacing preferences of both this view and the adjacent views on their shared edge.

Discussion

Call this method from your implementation of Layout protocol methods if you need to measure the default spacing between two views in a custom layout. Call the method on the first view’s preferences instance, and provide the second view’s preferences instance as input.

For example, consider two views that appear in a custom horizontal stack. The following distance call gets the preferred spacing between these views, where spacing1 contains the preferences of a first view, and spacing2 contains the preferences of a second view:

let distance = spacing1.distance(to: spacing2, axis: .horizontal)

The method first determines, based on the axis and the ordering, that the views abut on the trailing edge of the first view and the leading edge of the second. It then gets the spacing preferences for the corresponding edges of each view, and returns the greater of the two values. This results in the smallest value that provides enough space to satisfy the preferences of both views.