#40: Add OnboardingSplashScreen from EI.

Update SplashScreen for EXI

ElementX/Sources/Other/HTMLParsing/AttributedStringBuilder.swift

@@ -140,7 +140,7 @@ struct AttributedStringBuilder: AttributedStringBuilderProtocol {
         attributedString.enumerateAttribute(.backgroundColor, in: .init(location: 0, length: attributedString.length), options: []) { value, range, _ in
             if let value = value as? UIColor,
                value == temporaryCodeBlockMarkingColor {
-                attributedString.addAttribute(.backgroundColor, value: Asset.Colors.codeBlockBackground.color as Any, range: range)
+                attributedString.addAttribute(.backgroundColor, value: UIColor.element.quinaryContent as Any, range: range)
             }
         }
     }

ElementX/Sources/Other/SwiftUI/Views/ViewFrameReader/FramePreferenceKey.swift

@@ -0,0 +1,26 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import SwiftUI
+
+/// A SwiftUI `PreferenceKey` for `CGRect` values such as a view's frame.
+struct FramePreferenceKey: PreferenceKey {
+    static var defaultValue: CGRect = .zero
+    
+    static func reduce(value: inout CGRect, nextValue: () -> CGRect) {
+        value = nextValue()
+    }
+}

ElementX/Sources/Other/SwiftUI/Views/ViewFrameReader/ViewFrameReader.swift

@@ -0,0 +1,42 @@
+// 
+// Copyright 2021 New Vector Ltd
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+import Foundation
+import SwiftUI
+
+/// Used to calculate the frame of a view.
+///
+/// Useful in situations as with `ZStack` where you might want to layout views using alignment guides.
+/// ```
+/// @State private var frame: CGRect = CGRect.zero
+/// ...
+/// SomeView()
+///    .background(ViewFrameReader(frame: $frame))
+/// ```
+struct ViewFrameReader: View {
+    @Binding var frame: CGRect
+    
+    var body: some View {
+        GeometryReader { geometry in
+            Color.clear
+                .preference(key: FramePreferenceKey.self,
+                            value: geometry.frame(in: .local))
+        }
+        .onPreferenceChange(FramePreferenceKey.self) {
+            frame = $0
+        }
+    }
+}