improved performance and battery usage on older devices

lib/view/pages/talk/widgets/chat_bubble.dart

@@ -59,6 +59,13 @@ class _ChatBubbleState extends State<ChatBubble>
     with SingleTickerProviderStateMixin, DownloadTrigger<ChatBubble> {
   late ChatMessage message;
 
+  // The parsed message and its widget are only rebuilt when their inputs
+  // change. The bubble itself rebuilds on every chat emit, swipe frame and
+  // keyboard frame; re-running rich-object parsing, linkify/Markdown and emoji
+  // detection each time is what makes long chats stutter.
+  Object? _messageKey;
+  late Widget _messageWidget;
+
   Offset _position = Offset.zero;
   Offset _dragStartPosition = Offset.zero;
   bool _swipeActionArmed = false;
@@ -185,12 +192,34 @@ class _ChatBubbleState extends State<ChatBubble>
     }
   }
 
-  @override
-  Widget build(BuildContext context) {
+  void _updateMessage(BuildContext context) {
+    final style = _messageTextStyle(context);
+    final renderMarkdown =
+        widget.bubbleData.markdown &&
+        widget.bubbleData.messageType ==
+            GetRoomResponseObjectMessageType.comment;
+    final key = (
+      widget.bubbleData,
+      widget.highlightQuery,
+      style,
+      renderMarkdown,
+    );
+    if (key == _messageKey) return;
+    _messageKey = key;
     message = ChatMessage(
       originalMessage: widget.bubbleData.message,
       originalData: widget.bubbleData.messageParameters,
     );
+    _messageWidget = message.getWidget(
+      highlightQuery: widget.highlightQuery,
+      style: style,
+      renderMarkdown: renderMarkdown,
+    );
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    _updateMessage(context);
     final showActorDisplayName =
         _rendersAsCommentBubble &&
         widget.chatData.type != GetRoomResponseObjectConversationType.oneToOne;
@@ -277,14 +306,7 @@ class _ChatBubbleState extends State<ChatBubble>
                 actorText: actorText,
                 actorWidget: actorWidget,
                 timeText: timeText,
-                messageWidget: message.getWidget(
-                  highlightQuery: widget.highlightQuery,
-                  style: _messageTextStyle(context),
-                  renderMarkdown:
-                      widget.bubbleData.markdown &&
-                      widget.bubbleData.messageType ==
-                          GetRoomResponseObjectMessageType.comment,
-                ),
+                messageWidget: _messageWidget,
                 parent: parent,
                 bubbleData: widget.bubbleData,
                 isSender: widget.isSender,
@@ -350,10 +372,12 @@ class _BubbleContent extends StatelessWidget {
   Widget build(BuildContext context) => MergeSemantics(
     child: Container(
       constraints: BoxConstraints(
-        maxWidth: MediaQuery.of(context).size.width * 0.9,
+        maxWidth: MediaQuery.sizeOf(context).width * 0.9,
         minWidth: showActorDisplayName
-            ? actorText.size.width
-            : timeText.size.width + (isSender ? spacing + timeIconSize : 0) + 3,
+            ? actorText.measuredWidth(context)
+            : timeText.measuredWidth(context) +
+                  (isSender ? spacing + timeIconSize : 0) +
+                  3,
       ),
       child: Stack(
         children: [