X-Git-Url: https://git.quassel-irc.org/?a=blobdiff_plain;ds=sidebyside;f=src%2Fqtui%2Fchatview.cpp;h=1a24c6ff10162e3a45ac1359edd941dc77b9d2bc;hb=c8ddabf364eff2400c61cea395aefe69eb8ba1b3;hp=3074882df1ffdcbdb571eb770b10efb2fc4441e6;hpb=a95ad2de573027f9bee36db972bcae4195168d0c;p=quassel.git

diff --git a/src/qtui/chatview.cpp b/src/qtui/chatview.cpp
index 3074882d..1a24c6ff 100644
--- a/src/qtui/chatview.cpp
+++ b/src/qtui/chatview.cpp
@@ -1,5 +1,5 @@
 /***************************************************************************
- *   Copyright (C) 2005-2020 by the Quassel Project                        *
+ *   Copyright (C) 2005-2022 by the Quassel Project                        *
  *   devel@quassel-irc.org                                                 *
  *                                                                         *
  *   This program is free software; you can redistribute it and/or modify  *
@@ -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
@@ -100,8 +103,7 @@ bool ChatView::event(QEvent* event)
         case Qt::Key_Down:
         case Qt::Key_PageUp:
         case Qt::Key_PageDown:
-            if (!verticalScrollBar()->isVisible()) {
-                scene()->requestBacklog();
+            if (requestBacklogForScroll()) {
                 return true;
             }
         default:
@@ -110,7 +112,7 @@ bool ChatView::event(QEvent* event)
     }
 
     if (event->type() == QEvent::TouchBegin && ((QTouchEvent*)event)->device()->type() == QTouchDevice::TouchScreen) {
-        // Enable scrolling by draging, disable selecting/clicking content
+        // Enable scrolling by dragging, disable selecting/clicking content
         setDragMode(QGraphicsView::ScrollHandDrag);
         setInteractive(false);
         // if scrollbar is not visible we need to request backlog below else we need to accept
@@ -145,8 +147,7 @@ bool ChatView::event(QEvent* event)
     if (event->type() == QEvent::Wheel
         || (event->type() == QEvent::TouchBegin && ((QTouchEvent*)event)->device()->type() == QTouchDevice::TouchScreen)
         || event->type() == QEvent::TouchUpdate) {
-        if (!verticalScrollBar()->isVisible()) {
-            scene()->requestBacklog();
+        if (requestBacklogForScroll()) {
             return true;
         }
     }
@@ -159,6 +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
@@ -168,7 +191,7 @@ void ChatView::resizeEvent(QResizeEvent* event)
 
     // if scrolling to bottom, do it immediately.
     if (atBottom) {
-        // we can reduce viewport updates if we scroll to the bottom allready at the beginning
+        // we can reduce viewport updates if we scroll to the bottom already at the beginning
         verticalScrollBar()->setValue(verticalScrollBar()->maximum());
     }
 
@@ -409,6 +432,24 @@ void ChatView::setHasCache(ChatLine* line, bool hasCache)
         _linesWithCache.remove(line);
 }
 
+bool ChatView::requestBacklogForScroll()
+{
+    if (!verticalScrollBar()->isVisible()) {
+        // Not able to scroll, fetch backlog
+        //
+        // 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;
+    }
+    else {
+        // Scrollbar already visible, no backlog requested
+        return false;
+    }
+}
+
 void ChatView::checkChatLineCaches()
 {
     qreal top = mapToScene(viewport()->rect().topLeft()).y() - 10;  // some grace area to avoid premature cleaning