ChatLog: Autoscroll while selecting

src/chatlog/chatlog.cpp

@@ -23,6 +23,7 @@
 #include <QApplication>
 #include <QClipboard>
 #include <QAction>
+#include <QTimer>
 
 template<class T>
 T clamp(T x, T min, T max)
@@ -62,6 +63,12 @@ ChatLog::ChatLog(QWidget* parent)
     {
         copySelectedText();
     });
+
+    selectionTimer = new QTimer(this);
+    selectionTimer->setInterval(1000/60);
+    selectionTimer->setSingleShot(false);
+    selectionTimer->start();
+    connect(selectionTimer, &QTimer::timeout, this, &ChatLog::onSelectionTimerTimeout);
 }
 
 ChatLog::~ChatLog()
@@ -243,6 +250,8 @@ void ChatLog::mouseReleaseEvent(QMouseEvent* ev)
 
         emit customContextMenuRequested(ev->pos());
     }
+
+    selectionScrollDir = NoDirection;
 }
 
 void ChatLog::mouseMoveEvent(QMouseEvent* ev)
@@ -253,6 +262,15 @@ void ChatLog::mouseMoveEvent(QMouseEvent* ev)
 
     if(ev->buttons() & Qt::LeftButton)
     {
+        //autoscroll
+        if(ev->pos().y() < 0)
+            selectionScrollDir = Up;
+        else if(ev->pos().y() > height())
+            selectionScrollDir = Down;
+        else
+            selectionScrollDir = NoDirection;
+
+        //select
         if(selectionMode == None && (clickPos - ev->pos()).manhattanLength() > QApplication::startDragDistance())
         {
             QPointF sceneClickPos = mapToScene(clickPos.toPoint());
@@ -579,3 +597,20 @@ void ChatLog::updateMultiSelectionRect()
         selGraphItem->hide();
     }
 }
+
+void ChatLog::onSelectionTimerTimeout()
+{
+    const int scrollSpeed = 10;
+
+    switch(selectionScrollDir)
+    {
+    case Up:
+        verticalScrollBar()->setValue(verticalScrollBar()->value() - scrollSpeed);
+        break;
+    case Down:
+        verticalScrollBar()->setValue(verticalScrollBar()->value() + scrollSpeed);
+        break;
+    default:
+        break;
+    }
+}

src/chatlog/chatlog.h

@@ -26,6 +26,7 @@
 
 class QGraphicsScene;
 class QGraphicsRectItem;
+class QTimer;
 class ChatLineContent;
 class ToxFile;
 
@@ -81,6 +82,9 @@ protected:
 
     void updateMultiSelectionRect();
 
+private slots:
+    void onSelectionTimerTimeout();
+
 private:
     enum SelectionMode {
         None,
@@ -88,6 +92,12 @@ private:
         Multi,
     };
 
+    enum AutoScrollDirection {
+        NoDirection,
+        Up,
+        Down,
+    };
+
     QGraphicsScene* scene = nullptr;
     QList<ChatLine::Ptr> lines;
     QList<ChatLine::Ptr> visibleLines;
@@ -105,6 +115,8 @@ private:
     QPointF clickPos;
     QPointF lastPos;
     QGraphicsRectItem* selGraphItem = nullptr;
+    QTimer* selectionTimer = nullptr;
+    AutoScrollDirection selectionScrollDir = NoDirection;
 
     // actions
     QAction* copyAction = nullptr;