[network/ruqola] src/widgets/room: Remeasure message rows when their height changes

Git commit 6268a0e336ae1ef585fc5428670c270f68ebeefe by Laurent Montel, on behalf of Till Adam.
Committed on 28/07/2026 at 11:54.
Pushed by tilladam into branch 'master'.

Remeasure message rows when their height changes

The message list reacted to two height-changing events with a bare repaint
and no relayout, so rows kept the stale heights held in the delegate's
per-message size-hint cache:

- Marking a room read (Room::lastSeenChanged) removes the "unread messages"
  marker, which had reserved a band of vertical space at the top of the row
  it preceded; the row then stayed tall with the band left as dead space.
- Switching message style (Compact/Normal/Cozy) recreates the layout and
  clears the size-hint cache in switchMessageLayout(), but the previous
  style's row geometry lingered until an unrelated event forced a relayout.

Give lastSeenChanged its own slot that clears the stale size hints and
schedules a relayout, and add the relayout to slotUpdateView() (the
style-switch path already clears the cache). Row heights now update as soon
as they change.

M  +21   -2    src/widgets/room/messagelistview.cpp
M  +1    -0    src/widgets/room/messagelistview.h

https://invent.kde.org/network/ruqola/-/commit/6268a0e336ae1ef585fc5428670c270f68ebeefe

diff --git a/src/widgets/room/messagelistview.cpp b/src/widgets/room/messagelistview.cpp
index e04bb10064..824b0f7bb3 100644
--- a/src/widgets/room/messagelistview.cpp
+++ b/src/widgets/room/messagelistview.cpp
@@ -140,18 +140,37 @@ void MessageListView::paintEvent(QPaintEvent *e)
 
 void MessageListView::slotUpdateView()
 {
+    // A message-style switch (Compact/Normal/Cozy) recreates the layout and clears the delegate's
+    // size-hint cache in switchMessageLayout(), but without a relayout the view keeps the previous
+    // style's row geometry until an unrelated event (scroll/resize/new message) triggers one.
+    // Remeasure here so the switch takes effect immediately. (A colour-scheme refresh also arrives
+    // via this slot and harmlessly relayouts.)
+    scheduleDelayedItemsLayout();
     viewport()->update();
 }
 
+void MessageListView::slotLastSeenChanged()
+{
+    // The "unread messages" marker reserves a band of vertical space at the top of the row it
+    // precedes, and that extra height is baked into the delegate's per-message size-hint cache
+    // (keyed by message id only). When the room is marked read the marker disappears
+    // (DisplayLastSeenMessage flips to false), but a plain repaint would keep the cached row
+    // height and leave the band as dead space — the row stays tall. Drop the now-stale sizes and
+    // relayout so the affected row shrinks back. Mark-as-read is infrequent, so clearing the
+    // whole cache (rather than hunting the single boundary row) is a fine trade-off.
+    mMessageListDelegate->clearSizeHintCache();
+    scheduleDelayedItemsLayout();
+}
+
 void MessageListView::setRoom(Room *room)
 {
     if (mRoom) {
-        disconnect(mRoom, &Room::lastSeenChanged, this, &MessageListView::slotUpdateView);
+        disconnect(mRoom, &Room::lastSeenChanged, this, &MessageListView::slotLastSeenChanged);
         mMessageListDelegate->clearSelection();
     }
     mRoom = room;
     if (mRoom) {
-        connect(mRoom, &Room::lastSeenChanged, this, &MessageListView::slotUpdateView);
+        connect(mRoom, &Room::lastSeenChanged, this, &MessageListView::slotLastSeenChanged);
     }
 }
 
diff --git a/src/widgets/room/messagelistview.h b/src/widgets/room/messagelistview.h
index 59a3b0acdb..28fe3b4198 100644
--- a/src/widgets/room/messagelistview.h
+++ b/src/widgets/room/messagelistview.h
@@ -94,6 +94,7 @@ private:
     [[nodiscard]] LIBRUQOLAWIDGETS_NO_EXPORT QString generatePermalink(const QString &messageId) const;
     LIBRUQOLAWIDGETS_NO_EXPORT void slotShowUserInfo(const QString &userName);
     LIBRUQOLAWIDGETS_NO_EXPORT void slotUpdateView();
+    LIBRUQOLAWIDGETS_NO_EXPORT void slotLastSeenChanged();
     LIBRUQOLAWIDGETS_NO_EXPORT void slotTranslate(const QString &from, const QString &to, const QPersistentModelIndex &modelIndex);
     LIBRUQOLAWIDGETS_NO_EXPORT void slotTextToSpeech(const QModelIndex &index);
     LIBRUQOLAWIDGETS_NO_EXPORT void addDebugMenu(QMenu &menu, const QModelIndex &index);