Full-Screen Button

// Must be hosted inside a NavigationStack
NavigationStack {
    SWFullScreenButton()
}

// Custom copy
NavigationStack {
    SWFullScreenButton(
        title: "SmileMax",
        subtitle: "Daily smile analytics",
        footer: "Open"
    )
}

// Custom palette and shape
NavigationStack {
    SWFullScreenButton(
        gradientColors: [.purple, .pink],
        cornerRadius: 24
    )
}

• Why the zoom transition? An earlier version of this component animated its own .frame from compactSize up to UIScreen bounds with withAnimation(.bouncy). The bounce was the entire point of the component — but inside any NavigationStack or ScrollView, SwiftUI's layout system clamped the frame to the parent's content area, so the card grew toward the toolbar / scroll bounds and never reached the physical screen edges. A second iteration switched to .fullScreenCover, which fixed the "fills the screen" problem but threw away the original spring-into-fullscreen feel — .fullScreenCover's generic slide-up modal is something any vanilla SwiftUI app gets for free, so the component became redundant. The iOS 18 zoom transition gives back the best of both: a continuous, geometry-matched spring from the compact card into a real edge-to-edge view, with no manual screen-size measurement and no container clamping.

• Dismiss gestures. The expanded view supports two dismiss paths: (1) tap anywhere on the card — the destination view holds @Environment(\.dismiss) and calls it on onTapGesture, which pops the NavigationStack and triggers the reverse zoom animation; (2) edge-swipe-back — the system-provided gesture for any pushed view, also reverse-zooms. The tap path matches the original "tap to toggle" intent of the component; the edge-swipe path is iOS-native muscle memory.

• Why NavigationStack is required. The zoom transition is implemented as a NavigationLink push with a .navigationTransition(.zoom(...)) modifier on the destination. Without a host NavigationStack, the NavigationLink silently renders as a plain button and the transition never fires. The hosting requirement is what lets the zoom escape any ScrollView / nested VStack — the push goes through the stack, not through the layout tree.

• iOS 18+ only. Both .matchedTransitionSource(id:in:) and .navigationTransition(.zoom(sourceID:in:)) were introduced in iOS 18, ShipSwift's minimum, so no @available annotation is needed. The file is named SWFullScreenButton+iOS.swift so Xcode's per-file platform filter can exclude it from macOS targets — do not wrap the body in #if os(iOS) as a substitute (per the ShipSwift convention, platform filtering is a build setting).

• Tap target. The whole compact card is the NavigationLink label; .buttonStyle(.plain) removes the default tint so the gradient renders cleanly.

• Shadow flicker on reverse zoom — the real fix. The iOS 18 zoom transition snapshots the source view's bounds raster. A .shadow(_:) is drawn outside those bounds, so the snapshot never carries it — regardless of whether the shadow is written as a trailing modifier (.shadow(radius: 30)) or embedded inside a .background { RoundedRectangle().shadow(...) }. The visible symptom: during the reverse zoom the shadow is absent, and one frame after the system hands off from the destination snapshot back to the live source view, the shadow "pops in." We solve this with an animated radius: a @State private var shadowRadius: CGFloat = 30 drives the background's shadow, the destination's .onAppear sets it to 0, and .onDisappear runs withAnimation(.easeOut(duration: 0.25)) { shadowRadius = 30 }. Reverse zoom completes with shadowRadius == 0, then the shadow fades back in smoothly — masking the snapshot hand-off frame. This is the only reliable fix on iOS 18; .compositingGroup(), .drawingGroup(), and reordering the modifiers do not extend the snapshot bounds.