From: Manuel Nickschas <sputnick@quassel-irc.org>
Date: Wed, 27 Aug 2008 12:32:00 +0000 (+0200)
Subject: Improve scrolling and dynamic backlog fetching behavior
X-Git-Tag: 0.3.0~4
X-Git-Url: https://git.quassel-irc.org/?p=quassel.git;a=commitdiff_plain;h=e920325766f65e66132c20e4cb1da8f8e3f5e030

Improve scrolling and dynamic backlog fetching behavior

Fixes BR #248, #296
---

diff --git a/src/qtui/chatscene.cpp b/src/qtui/chatscene.cpp
index 3eacdc4b..bed0d65c 100644
--- a/src/qtui/chatscene.cpp
+++ b/src/qtui/chatscene.cpp
@@ -134,6 +134,7 @@ void ChatScene::rowsInserted(const QModelIndex &index, int start, int end) {
     }
     setSceneRect(QRectF(0, 0, _width, _height));
     emit heightChanged(_height);
+    emit heightChangedAt(_lines.at(start)->y(), h);
   }
 }
 
diff --git a/src/qtui/chatscene.h b/src/qtui/chatscene.h
index f97787ea..45ab0f40 100644
--- a/src/qtui/chatscene.h
+++ b/src/qtui/chatscene.h
@@ -65,6 +65,7 @@ class ChatScene : public QGraphicsScene {
 
   signals:
     void heightChanged(qreal height);
+    void heightChangedAt(qreal ypos, qreal hdiff);
 
   protected:
     virtual void mouseMoveEvent(QGraphicsSceneMouseEvent *mouseEvent);
diff --git a/src/qtui/chatview.cpp b/src/qtui/chatview.cpp
index 1eee2245..02d61b26 100644
--- a/src/qtui/chatview.cpp
+++ b/src/qtui/chatview.cpp
@@ -51,9 +51,10 @@ void ChatView::init(MessageFilter *filter) {
   setInteractive(true);
 
   _scene = new ChatScene(filter, filter->idString(), this);
-  connect(_scene, SIGNAL(heightChanged(qreal)), this, SLOT(sceneHeightChanged(qreal)));
+  connect(_scene, SIGNAL(heightChangedAt(qreal, qreal)), this, SLOT(sceneHeightChangedAt(qreal, qreal)));
   setScene(_scene);
 
+  _lastScrollbarPos = 0;
   connect(verticalScrollBar(), SIGNAL(valueChanged(int)), this, SLOT(verticalScrollbarChanged(int)));
 }
 
@@ -62,24 +63,28 @@ void ChatView::resizeEvent(QResizeEvent *event) {
   verticalScrollBar()->setValue(verticalScrollBar()->maximum());
 }
 
-void ChatView::sceneHeightChanged(qreal h) {
-  Q_UNUSED(h)
-  bool scrollable = qAbs(verticalScrollBar()->value() - verticalScrollBar()->maximum()) <= 2; // be a bit tolerant here, also FIXME (why we need this?)
+void ChatView::sceneHeightChangedAt(qreal ypos, qreal hdiff) {
   setSceneRect(scene()->sceneRect());
-  if(scrollable) verticalScrollBar()->setValue(verticalScrollBar()->maximum());
+  int y = mapFromScene(0, ypos).y();
+  if(y <= viewport()->height() + 2) {  // be a bit tolerant here, also FIXME (why we need the 2px?)
+    verticalScrollBar()->setValue(verticalScrollBar()->value() + hdiff);
+  }
 }
 
 void ChatView::verticalScrollbarChanged(int newPos) {
   QAbstractSlider *vbar = verticalScrollBar();
   Q_ASSERT(vbar);
 
-  int relativePos = 100;
-  if(vbar->maximum() - vbar->minimum() != 0)
-    relativePos = (newPos - vbar->minimum()) * 100 / (vbar->maximum() - vbar->minimum());
+  if(newPos < _lastScrollbarPos) {
+    int relativePos = 100;
+    if(vbar->maximum() - vbar->minimum() != 0)
+      relativePos = (newPos - vbar->minimum()) * 100 / (vbar->maximum() - vbar->minimum());
 
-  if(relativePos < 20) {
-    scene()->requestBacklog();
+    if(relativePos < 20) {
+      scene()->requestBacklog();
+    }
   }
+  _lastScrollbarPos = newPos;
 }
 
 MsgId ChatView::lastMsgId() const {
diff --git a/src/qtui/chatview.h b/src/qtui/chatview.h
index 21367fe4..27713ea2 100644
--- a/src/qtui/chatview.h
+++ b/src/qtui/chatview.h
@@ -48,13 +48,14 @@ protected:
   virtual void resizeEvent(QResizeEvent *event);
 
 protected slots:
-  virtual void sceneHeightChanged(qreal height);
+  virtual void sceneHeightChangedAt(qreal ypos, qreal hdiff);
   virtual void verticalScrollbarChanged(int);
-  
+
 private:
   void init(MessageFilter *filter);
 
   ChatScene *_scene;
+  int _lastScrollbarPos;
 };