RoomScreenViewModel is now TimelineViewModel (#3157)

Co-authored-by: Stefan Ceriu <stefanc@matrix.org>
2026-11-04 10:33:45 +00:00 · 2024-08-13 13:36:40 +02:00
parent 4519275559
commit 1ad361a6e8
88 changed files with 2266 additions and 1973 deletions
@@ -0,0 +1,109 @@
+//
+// Copyright 2023 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 custom layout used for quotes and content when using the bubbles timeline style.
+///
+/// A custom layout is required as the embedded quote bubbles should fill the entire width of
+/// the message bubble, without causing the width of the bubble to fill all of the available space.
+struct TimelineBubbleLayout: Layout {
+    struct Cache {
+        var sizes = [Int: [ProposedViewSize: CGSize]]()
+    }
+    
+    /// The spacing between the components in the bubble.
+    let spacing: CGFloat
+    
+    /// Layout priority constants for the bubble content. These priorities are abused within
+    /// `TimelineBubbleLayout` to create the layout we would like. They aren't
+    /// used in the expected way that SwiftUI would normally use layout priorities.
+    enum Priority {
+        /// The priority of hidden quote bubbles that are only used for layout calculations.
+        static let hiddenQuote: Double = -1
+        /// The priority of visible quote bubbles that are placed in the view with a full width.
+        static let visibleQuote: Double = 0
+        /// The priority of regular text that is used for layout calculations and placed in the view.
+        static let regularText: Double = 1
+    }
+    
+    func makeCache(subviews: Subviews) -> Cache {
+        Cache()
+    }
+    
+    func updateCache(_ cache: inout Cache, subviews: Subviews) {
+        // A subview changed, reset everything
+        cache = Cache()
+    }
+    
+    func sizeThatFits(proposal: ProposedViewSize, subviews: Subviews, cache: inout Cache) -> CGSize {
+        guard !subviews.isEmpty else { return .zero }
+        
+        // Calculate the natural size using the regular text and non-greedy quote bubbles.
+        let layoutSubviews = subviews.filter { $0.priority != Priority.visibleQuote }
+
+        let subviewSizes = layoutSubviews.map { size(for: $0, subviews: subviews, proposedSize: proposal, cache: &cache) }
+        
+        let maxWidth = subviewSizes.map(\.width).reduce(0, max)
+        let totalHeight = subviewSizes.map(\.height).reduce(0, +)
+        let totalSpacing = CGFloat(layoutSubviews.count - 1) * spacing
+        
+        return CGSize(width: maxWidth, height: totalHeight + totalSpacing)
+    }
+    
+    func placeSubviews(in bounds: CGRect, proposal: ProposedViewSize, subviews: Subviews, cache: inout Cache) {
+        guard !subviews.isEmpty else { return }
+        
+        // Calculate the width using the regular text and the non-greedy quote bubbles.
+        let layoutSubviews = subviews.filter { $0.priority != Priority.visibleQuote }
+        let maxWidth = layoutSubviews.map { size(for: $0, subviews: subviews, proposedSize: proposal, cache: &cache).width }.reduce(0, max)
+        
+        // Place the regular text and greedy quote bubbles using the calculated width.
+        let visibleSubviews = subviews.filter { $0.priority != Priority.hiddenQuote }
+
+        let subviewSizes = visibleSubviews.map { size(for: $0, subviews: subviews, proposedSize: ProposedViewSize(width: maxWidth, height: proposal.height), cache: &cache) }
+        
+        var y = bounds.minY
+        for index in visibleSubviews.indices {
+            let height = subviewSizes[index].height
+            visibleSubviews[index].place(at: CGPoint(x: bounds.minX, y: y),
+                                         anchor: .topLeading,
+                                         proposal: ProposedViewSize(width: maxWidth, height: height))
+            y += height + spacing
+        }
+    }
+    
+    // MARK: - Private
+    
+    private func size(for subview: LayoutSubview, subviews: LayoutSubviews, proposedSize: ProposedViewSize, cache: inout Cache) -> CGSize {
+        guard let index = subviews.firstIndex(of: subview) else {
+            fatalError()
+        }
+        
+        if cache.sizes[index] == nil {
+            cache.sizes[index] = [:]
+        }
+        
+        if let cachedSize = cache.sizes[index]?[proposedSize] {
+            return cachedSize
+        }
+        
+        let size = subview.sizeThatFits(proposedSize)
+        
+        cache.sizes[index]?[proposedSize] = size
+        return size
+    }
+}