Simplify the layout of the onboarding splash screen

RiotSwiftUI/Modules/Onboarding/Common/OnboardingMetrics.swift

@@ -18,7 +18,6 @@ import SwiftUI
 
 /// Metrics used across the entire onboarding flow.
 struct OnboardingMetrics {
-    static let maxContentWidth: CGFloat = 600
     static let maxContentHeight: CGFloat = 750
 
     /// The padding used between the top of the main content and the navigation bar.

RiotSwiftUI/Modules/Onboarding/SplashScreen/OnboardingSplashScreenModels.swift

@@ -24,7 +24,6 @@ struct OnboardingSplashScreenPageContent {
     let message: String
     let image: ImageAsset
     let darkImage: ImageAsset
-    let gradient: Gradient
 }
 
 // MARK: View model
@@ -38,19 +37,14 @@ enum OnboardingSplashScreenViewModelResult {
 
 struct OnboardingSplashScreenViewState: BindableState, CustomDebugStringConvertible {
 
-    // MARK: - Constants
-
-    private enum Constants {
-        static let gradientColors = [
-            Color(red: 0.95, green: 0.98, blue: 0.96),
-            Color(red: 0.89, green: 0.96, blue: 0.97),
-            Color(red: 0.95, green: 0.89, blue: 0.97),
-            Color(red: 0.81, green: 0.95, blue: 0.91),
-            Color(red: 0.95, green: 0.98, blue: 0.96)
-        ]
-    }
-
-    // MARK: - Properties
+    /// The colours of the background gradient shown behind the 4 pages.
+    private let gradientColors = [
+        Color(red: 0.95, green: 0.98, blue: 0.96),
+        Color(red: 0.89, green: 0.96, blue: 0.97),
+        Color(red: 0.95, green: 0.89, blue: 0.97),
+        Color(red: 0.81, green: 0.95, blue: 0.91),
+        Color(red: 0.95, green: 0.98, blue: 0.96)
+    ]
 
     /// An array containing all content of the carousel pages
     let content: [OnboardingSplashScreenPageContent]
@@ -61,6 +55,13 @@ struct OnboardingSplashScreenViewState: BindableState, CustomDebugStringConverti
         "OnboardingSplashScreenViewState at page \(bindings.pageIndex)."
     }
 
+    /// The background gradient for all 4 pages and the hidden page at the start of the carousel.
+    var backgroundGradient: Gradient {
+        // Include the extra stop for the hidden page at the start of the carousel.
+        let hiddenPageColor = gradientColors[gradientColors.count - 2]
+        return Gradient(colors: [hiddenPageColor] + gradientColors)
+    }
+
     init() {
         // The pun doesn't translate, so we only use it for English.
         let locale = Locale.current
@@ -70,23 +71,19 @@ struct OnboardingSplashScreenViewState: BindableState, CustomDebugStringConverti
             OnboardingSplashScreenPageContent(title: VectorL10n.onboardingSplashPage1Title,
                                               message: VectorL10n.onboardingSplashPage1Message,
                                               image: Asset.Images.onboardingSplashScreenPage1,
-                                              darkImage: Asset.Images.onboardingSplashScreenPage1Dark,
-                                              gradient: Gradient(colors: [Constants.gradientColors[0], Constants.gradientColors[1]])),
+                                              darkImage: Asset.Images.onboardingSplashScreenPage1Dark),
             OnboardingSplashScreenPageContent(title: VectorL10n.onboardingSplashPage2Title,
                                               message: VectorL10n.onboardingSplashPage2Message,
                                               image: Asset.Images.onboardingSplashScreenPage2,
-                                              darkImage: Asset.Images.onboardingSplashScreenPage2Dark,
-                                              gradient: Gradient(colors: [Constants.gradientColors[1], Constants.gradientColors[2]])),
+                                              darkImage: Asset.Images.onboardingSplashScreenPage2Dark),
             OnboardingSplashScreenPageContent(title: VectorL10n.onboardingSplashPage3Title,
                                               message: VectorL10n.onboardingSplashPage3Message,
                                               image: Asset.Images.onboardingSplashScreenPage3,
-                                              darkImage: Asset.Images.onboardingSplashScreenPage3Dark,
-                                              gradient: Gradient(colors: [Constants.gradientColors[2], Constants.gradientColors[3]])),
+                                              darkImage: Asset.Images.onboardingSplashScreenPage3Dark),
             OnboardingSplashScreenPageContent(title: page4Title,
                                               message: VectorL10n.onboardingSplashPage4Message,
                                               image: Asset.Images.onboardingSplashScreenPage4,
-                                              darkImage: Asset.Images.onboardingSplashScreenPage4Dark,
-                                              gradient: Gradient(colors: [Constants.gradientColors[3], Constants.gradientColors[4]])),
+                                              darkImage: Asset.Images.onboardingSplashScreenPage4Dark),
         ]
         self.bindings = OnboardingSplashScreenBindings()
     }

RiotSwiftUI/Modules/Onboarding/SplashScreen/View/OnboardingSplashScreen.swift

@@ -29,8 +29,6 @@ struct OnboardingSplashScreen: View {
     private var isLeftToRight: Bool { layoutDirection == .leftToRight }
     private var pageCount: Int { viewModel.viewState.content.count }
 
-    /// The dimensions of the stack with the action buttons and page indicator.
-    @State private var overlayFrame: CGRect = .zero
     /// A timer to automatically animate the pages.
     @State private var pageTimer: Timer?
     /// The amount of offset to apply when a drag gesture is in progress.
@@ -40,75 +38,52 @@ struct OnboardingSplashScreen: View {
 
     @ObservedObject var viewModel: OnboardingSplashScreenViewModel.Context
 
-    /// The main action buttons.
-    var buttons: some View {
-        VStack(spacing: 12) {
-            Button { viewModel.send(viewAction: .register) } label: {
-                Text(VectorL10n.onboardingSplashRegisterButtonTitle)
-            }
-            .buttonStyle(PrimaryActionButtonStyle())
-
-            Button { viewModel.send(viewAction: .login) } label: {
-                Text(VectorL10n.onboardingSplashLoginButtonTitle)
-                    .font(theme.fonts.body)
-                    .padding(12)
-            }
-        }
-    }
-
-    /// The only part of the UI that isn't inside of the carousel.
-    var overlay: some View {
-        VStack(spacing: 50) {
-            Color.clear
-            Color.clear
-
-            VStack {
-                OnboardingSplashScreenPageIndicator(pageCount: pageCount,
-                                                    pageIndex: viewModel.pageIndex)
-                Spacer()
-
-                buttons
-                    .padding(.horizontal, 16)
-                    .frame(maxWidth: OnboardingMetrics.maxContentWidth)
-                Spacer()
-            }
-            .background(ViewFrameReader(frame: $overlayFrame))
-        }
-    }
-
     var body: some View {
         GeometryReader { geometry in
-            ZStack(alignment: .leading) {
+            VStack(alignment: .leading) {
+                Spacer()
+                    .frame(height: OnboardingMetrics.spacerHeight(in: geometry))
 
                 // The main content of the carousel
-                HStack(spacing: 0) {
+                HStack(alignment: .top, spacing: 0) {
 
                     // Add a hidden page at the start of the carousel duplicating the content of the last page
-                    OnboardingSplashScreenPage(content: viewModel.viewState.content[pageCount - 1],
-                                               overlayHeight: overlayFrame.height + geometry.safeAreaInsets.bottom)
+                    OnboardingSplashScreenPage(content: viewModel.viewState.content[pageCount - 1])
                         .frame(width: geometry.size.width)
-                        .tag(-1)
 
-                    ForEach(0..<pageCount) { index in
-                        OnboardingSplashScreenPage(content: viewModel.viewState.content[index],
-                                                   overlayHeight: overlayFrame.height + geometry.safeAreaInsets.bottom)
+                    ForEach(0..<pageCount, id: \.self) { index in
+                        OnboardingSplashScreenPage(content: viewModel.viewState.content[index])
                             .frame(width: geometry.size.width)
-                            .tag(index)
                     }
 
                 }
-                .offset(x: (CGFloat(viewModel.pageIndex + 1) * -geometry.size.width) + dragOffset)
-                .gesture(
-                    DragGesture()
-                        .onChanged(handleDragGestureChange)
-                        .onEnded { handleDragGestureEnded($0, viewSize: geometry.size) }
-                )
+                .offset(x: pageOffset(in: geometry))
+
+                Spacer()
 
-                overlay
+                OnboardingSplashScreenPageIndicator(pageCount: pageCount,
+                                                    pageIndex: viewModel.pageIndex)
+                .frame(width: geometry.size.width)
+                .padding(.bottom)
+
+                Spacer()
+
+                buttons
                     .frame(width: geometry.size.width)
+                    .padding(.bottom, OnboardingMetrics.actionButtonBottomPadding)
+                    .padding(.bottom, geometry.safeAreaInsets.bottom > 0 ? 0 : 16)
+
+                Spacer()
+                    .frame(height: OnboardingMetrics.spacerHeight(in: geometry))
             }
+            .frame(maxHeight: .infinity)
+            .background(background.ignoresSafeArea().offset(x: pageOffset(in: geometry)))
+            .gesture(
+                DragGesture()
+                    .onChanged(handleDragGestureChange)
+                    .onEnded { handleDragGestureEnded($0, viewSize: geometry.size) }
+            )
         }
-        .background(theme.colors.background.ignoresSafeArea())
         .accentColor(theme.colors.accent)
         .navigationBarHidden(true)
         .onAppear {
@@ -118,6 +93,37 @@ struct OnboardingSplashScreen: View {
         .track(screen: .welcome)
     }
 
+    /// The main action buttons.
+    var buttons: some View {
+        VStack(spacing: 12) {
+            Button { viewModel.send(viewAction: .register) } label: {
+                Text(VectorL10n.onboardingSplashRegisterButtonTitle)
+            }
+            .buttonStyle(PrimaryActionButtonStyle())
+
+            Button { viewModel.send(viewAction: .login) } label: {
+                Text(VectorL10n.onboardingSplashLoginButtonTitle)
+                    .font(theme.fonts.body)
+                    .padding(12)
+            }
+        }
+        .padding(.horizontal, 16)
+        .readableFrame()
+    }
+
+    @ViewBuilder
+    /// The view's background, showing a gradient in light mode and a solid colour in dark mode.
+    var background: some View {
+        if !theme.isDark {
+            LinearGradient(gradient: viewModel.viewState.backgroundGradient,
+                           startPoint: .leading,
+                           endPoint: .trailing)
+                .flipsForRightToLeftLayoutDirection(true)
+        } else {
+            theme.colors.background
+        }
+    }
+
     // MARK: - Animation
 
     /// Starts the animation timer for an automatic carousel effect.
@@ -147,6 +153,11 @@ struct OnboardingSplashScreen: View {
         pageTimer.invalidate()
     }
 
+    /// The offset to apply to the `HStack` of pages.
+    private func pageOffset(in geometry: GeometryProxy) -> CGFloat {
+        (CGFloat(viewModel.pageIndex + 1) * -geometry.size.width) + dragOffset
+    }
+
     // MARK: - Gestures
 
     /// Whether or not a drag gesture is valid or not.

RiotSwiftUI/Modules/Onboarding/SplashScreen/View/OnboardingSplashScreenPage.swift

@@ -26,59 +26,42 @@ struct OnboardingSplashScreenPage: View {
     // MARK: Public
     /// The content that this page should display.
     let content: OnboardingSplashScreenPageContent
-    /// The height of the non-scrollable content in the splash screen.
-    let overlayHeight: CGFloat
 
     // MARK: - Views
 
-    @ViewBuilder
-    var backgroundGradient: some View {
-        if !theme.isDark {
-            LinearGradient(gradient: content.gradient, startPoint: .leading, endPoint: .trailing)
-                .flipsForRightToLeftLayoutDirection(true)
-        }
-    }
-
     var body: some View {
         VStack {
-            VStack {
-                Image(theme.isDark ? content.darkImage.name : content.image.name)
-                    .resizable()
-                    .scaledToFit()
-                    .frame(maxWidth: 300)
-                    .padding(20)
-                    .accessibilityHidden(true)
-
-                VStack(spacing: 8) {
-                    OnboardingTintedFullStopText(content.title)
-                        .font(theme.fonts.title2B)
-                        .foregroundColor(theme.colors.primaryContent)
-                    Text(content.message)
-                        .font(theme.fonts.body)
-                        .foregroundColor(theme.colors.secondaryContent)
-                        .multilineTextAlignment(.center)
-                }
-                .padding(.bottom)
-
-                Spacer()
-
-                // Prevent the content from clashing with the overlay content.
-                Spacer().frame(maxHeight: overlayHeight)
+            Image(theme.isDark ? content.darkImage.name : content.image.name)
+                .resizable()
+                .scaledToFit()
+                .frame(maxWidth: 310) // This value is problematic. 300 results in dropped frames
+                                      // on iPhone 12/13 Mini. 305 the same on iPhone 12/13. As of
+                                      // iOS 15, 310 seems fine on all supported screen widths 🤞.
+                .padding(20)
+                .accessibilityHidden(true)
+
+            VStack(spacing: 8) {
+                OnboardingTintedFullStopText(content.title)
+                    .font(theme.fonts.title2B)
+                    .foregroundColor(theme.colors.primaryContent)
+                Text(content.message)
+                    .font(theme.fonts.body)
+                    .foregroundColor(theme.colors.secondaryContent)
+                    .multilineTextAlignment(.center)
             }
-            .padding(.horizontal, 16)
-            .frame(maxWidth: OnboardingMetrics.maxContentWidth,
-                   maxHeight: OnboardingMetrics.maxContentHeight)
+            .fixedSize(horizontal: false, vertical: true)
         }
-        .frame(maxWidth: .infinity, maxHeight: .infinity)
-        .background(backgroundGradient.ignoresSafeArea())
+        .padding(.bottom)
+        .padding(.horizontal, 16)
+        .readableFrame()
     }
 }
 
 struct OnboardingSplashScreenPage_Previews: PreviewProvider {
     static let content = OnboardingSplashScreenViewState().content
     static var previews: some View {
         ForEach(0..<content.count, id:\.self) { index in
-            OnboardingSplashScreenPage(content: content[index], overlayHeight: 200)
+            OnboardingSplashScreenPage(content: content[index])
         }
     }
 }

changelog.d/6319.bugfix

@@ -0,0 +1 @@
+Authentication: Fix splash screen stuttering on some devices.