client: Workaround initial backlog fetch scrolling

[quassel.git] / src / qtui / chatview.cpp

diff --git a/src/qtui/chatview.cpp b/src/qtui/chatview.cpp
index f8fb586..918cec6 100644 (file)
--- a/src/qtui/chatview.cpp
+++ b/src/qtui/chatview.cpp
@@ -84,6 +84,9 @@ void ChatView::init(MessageFilter* filter)
     connect(verticalScrollBar(), &QAbstractSlider::valueChanged, this, &ChatView::verticalScrollbarChanged);
     _lastScrollbarPos = verticalScrollBar()->maximum();
 
+    // Workaround for the ChatView scrolling up a fair bit when scrollbar becomes visible
+    verticalScrollBar()->installEventFilter(this);
+
     connect(Client::networkModel(), &NetworkModel::markerLineSet, this, &ChatView::markerLineSet);
 
     // only connect if client is synched with a core
@@ -157,6 +160,28 @@ bool ChatView::event(QEvent* event)
     return QGraphicsView::event(event);
 }
 
+bool ChatView::eventFilter(QObject* watched, QEvent* event)
+{
+    QAbstractSlider* vbar = verticalScrollBar();
+    Q_ASSERT(vbar);
+
+    if (watched != vbar) {
+        // Ignore and pass through all events not featuring the scrollbar
+        return false;
+    }
+    if (event->type() == QEvent::Show) {
+        // FIXME: Workaround for the ChatView scrolling up a fair bit when transitioning from the
+        // vertical scrollbar not being visible, to becoming visible.  This happens especially
+        // often when no initial backlog is loaded.
+        if (_backlogRequestedBeforeScrollable) {
+            _backlogRequestedBeforeScrollable = false;
+            vbar->setValue(vbar->maximum());
+        }
+    }
+    // Pass through all events
+    return false;
+}
+
 void ChatView::resizeEvent(QResizeEvent* event)
 {
     // if view is currently scrolled to bottom, we want it that way after resizing
@@ -415,6 +440,7 @@ bool ChatView::requestBacklogForScroll()
         // Future improvement: continue fetching backlog in chunks until the scrollbar is visible,
         // or the beginning of the buffer has been reached.
         scene()->requestBacklog();
+        _backlogRequestedBeforeScrollable = true;
         // Backlog has been requested
         return true;
     }