windowResizeAnchor(_:)

Declaration

nonisolated func windowResizeAnchor(_ anchor: UnitPoint?) -> some View

Parameters

• anchor:

  The window point fixed under programmatic size changes caused by the content size of the window changing. Defaults to a system defined value when nil.

Return Value

A view whose scene resizes on anchor.

Discussion

In SwiftUI life cycle apps, this modifier can be used to control how a window anchors when animating: drive window animations by changing the size of a view in a way that causes the window size to change. Note that if the window size is decreasing and an animation is desired, it is often necessary to (temporarily, if desired) set the windowResizability(_:) to contentSize.

struct Scratchpad: App {
    var body: some Scene {
        WindowGroup {
            HeightResizingExample()
        }
        .windowResizability(.contentSize)
    }
}

struct HeightResizingExample: View {
    @State private var height: CGFloat = 300

    var body: some View {
        ZStack(alignment: .topLeading) {
            Color.red
                .overlay {
                    Text("Tap to toggle")
                        .foregroundStyle(.white)
                }
        }
        .onTapGesture {
            withAnimation(.easeInOut) {
                height = height == 300 ? 700 : 300
            }
        }
        .frame(width: 250, height: height)
        .windowResizeAnchor(.top)
    }
}

The default anchor varies by scene type and is used when anchor is nil. Generally, it resolves to the .topLeading corner.