How to create 3D effects like Cover Flow using ScrollView and GeometryReader
How to create 3D effects like Cover Flow using ScrollView and GeometryReader 관련
Updated for Xcode 15
If we combine GeometryReader with any view that can change position – such as something that has a drag gestures or is inside a List – we can create 3D effects that look great on the screen. GeometryReader allows us to read the coordinates for a view, and feed those values directly into a rotation3DEffect() modifier.
For example, we could create a Cover Flow-style scrolling effect by stacking up many text views horizontally in a scroll view, then applying rotation3DEffect() so that as they move in the scroll view they gently spin around, like this:
ScrollView(.horizontal, showsIndicators: false) {
HStack(spacing: 0) {
ForEach(1..<20) { num in
VStack {
GeometryReader { geo in
Text("Number \(num)")
.font(.largeTitle)
.padding()
.background(.red)
.rotation3DEffect(.degrees(-Double(geo.frame(in: .global).minX) / 8), axis: (x: 0, y: 1, z: 0))
.frame(width: 200, height: 200)
}
.frame(width: 200, height: 200)
}
}
}
}
You don't always need to use GeometryReader to get interesting effects like – you could something similar with a DragGesture(), for example. So, this code creates a card-like rectangle that can be dragged around in both X and Y axes, and uses two rotation3DEffect() modifiers to apply values from that drag:
struct ContentView: View {
@State var dragAmount = CGSize.zero
var body: some View {
VStack {
Rectangle()
.fill(LinearGradient(gradient: Gradient(colors: [.yellow, .red]), startPoint: .topLeading, endPoint: .bottomTrailing))
.frame(width: 200, height: 150)
.clipShape(RoundedRectangle(cornerRadius: 20))
.rotation3DEffect(.degrees(-Double(dragAmount.width) / 20), axis: (x: 0, y: 1, z: 0))
.rotation3DEffect(.degrees(Double(dragAmount.height / 20)), axis: (x: 1, y: 0, z: 0))
.offset(dragAmount)
.gesture(
DragGesture()
.onChanged { dragAmount = $0.translation }
.onEnded { _ in
withAnimation(.spring()) {
dragAmount = .zero
}
}
)
}
.frame(width: 400, height: 400)
}
}
As you drag the card around you'll see it rotates to give a perspective effect.
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