Implement all emoji text message boosting

ElementX/Sources/Other/EmojiDetection.swift

@@ -0,0 +1,66 @@
+//
+// 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 Foundation
+
+extension UnicodeScalar {
+    var isZeroWidthJoiner: Bool {
+        value == 8205
+    }
+    
+    var isKeycap: Bool {
+        value == 8419
+    }
+    
+    var isNumber: Bool {
+        switch value {
+        case 48...57:
+            return true
+        default:
+            return false
+        }
+    }
+}
+
+extension String {
+    var containsOnlyEmoji: Bool {
+        guard !isEmpty else {
+            return false
+        }
+        
+        var emojiMarkerCount = 0
+        for scalar in unicodeScalars {
+            let isEmojiMarker = scalar.properties.isEmoji ||
+                scalar.properties.isEmojiPresentation ||
+                scalar.isZeroWidthJoiner ||
+                scalar.properties.isDefaultIgnorableCodePoint ||
+                scalar.isKeycap
+            
+            guard isEmojiMarker else {
+                return false
+            }
+            
+            emojiMarkerCount += 1
+        }
+        
+        // Plain numbers like 0 return true for .isEmoji. We don't want that
+        let markersRequiringSiblings = unicodeScalars.filter {
+            $0.properties.isEmoji && $0.isNumber
+        }
+        
+        return markersRequiringSiblings.count != emojiMarkerCount && emojiMarkerCount == unicodeScalars.count
+    }
+}

ElementX/Sources/Screens/RoomScreen/View/Timeline/FormattedBodyText.swift

@@ -22,16 +22,35 @@ struct FormattedBodyText: View {
 
     private let attributedString: AttributedString
     private let additionalWhitespacesCount: Int
+    private let boostEmojiSize: Bool
 
     private var attributedComponents: [AttributedStringBuilderComponent] {
-        var attributedString = attributedString
-        attributedString.append(AttributedString(stringLiteral: additionalWhitespacesSuffix))
-        return attributedString.formattedComponents
+        var adjustedAttributedString = attributedString
+        adjustedAttributedString.append(AttributedString(stringLiteral: additionalWhitespacesSuffix))
+        
+        let string = String(attributedString.characters)
+        
+        if boostEmojiSize,
+           string.containsOnlyEmoji,
+           let range = adjustedAttributedString.range(of: string) {
+            adjustedAttributedString[range].font = .system(size: 48.0)
+        }
+        
+        return adjustedAttributedString.formattedComponents
     }
     
-    init(attributedString: AttributedString, additionalWhitespacesCount: Int = 0) {
+    init(attributedString: AttributedString,
+         additionalWhitespacesCount: Int = 0,
+         boostEmojiSize: Bool = false) {
         self.attributedString = attributedString
         self.additionalWhitespacesCount = additionalWhitespacesCount
+        self.boostEmojiSize = boostEmojiSize
+    }
+    
+    init(text: String, additionalWhitespacesCount: Int = 0, boostEmojiSize: Bool = false) {
+        self.init(attributedString: AttributedString(text),
+                  additionalWhitespacesCount: additionalWhitespacesCount,
+                  boostEmojiSize: boostEmojiSize)
     }
 
     // These is needed to create the slightly off inlined timestamp effect
@@ -123,12 +142,6 @@ struct FormattedBodyText: View {
     }
 }
 
-extension FormattedBodyText {
-    init(text: String, additionalWhitespacesCount: Int = 0) {
-        self.init(attributedString: AttributedString(text), additionalWhitespacesCount: additionalWhitespacesCount)
-    }
-}
-
 // MARK: - Previews
 
 struct FormattedBodyText_Previews: PreviewProvider {

ElementX/Sources/Screens/RoomScreen/View/Timeline/TextRoomTimelineView.swift

@@ -24,9 +24,13 @@ struct TextRoomTimelineView: View, TextBasedRoomTimelineViewProtocol {
     var body: some View {
         TimelineStyler(timelineItem: timelineItem) {
             if let attributedString = timelineItem.content.formattedBody {
-                FormattedBodyText(attributedString: attributedString, additionalWhitespacesCount: additionalWhitespaces)
+                FormattedBodyText(attributedString: attributedString,
+                                  additionalWhitespacesCount: additionalWhitespaces,
+                                  boostEmojiSize: true)
             } else {
-                FormattedBodyText(text: timelineItem.body, additionalWhitespacesCount: additionalWhitespaces)
+                FormattedBodyText(text: timelineItem.body,
+                                  additionalWhitespacesCount: additionalWhitespaces,
+                                  boostEmojiSize: true)
             }
         }
     }