sticking wheelEvents together for smooth visual experience.

map/framework.hpp

@@ -100,6 +100,9 @@ class FrameWork
   m2::PointD m_position;
   double m_confidenceRadius;
 
+  /// is AddRedrawCommand enabled?
+  bool m_isRedrawEnabled;
+
   void Invalidate()
   {
     m_windowHandle->invalidate();
@@ -113,7 +116,7 @@ class FrameWork
   void AddRedrawCommand()
   {
     yg::gl::RenderState const state = m_renderQueue.CopyState();
-    if (state.m_currentScreen != m_navigator.Screen())
+    if ((state.m_currentScreen != m_navigator.Screen()) && (m_isRedrawEnabled))
       AddRedrawCommandSure();
   }
 
@@ -163,7 +166,8 @@ public:
     : m_windowHandle(windowHandle),
       m_renderQueue(GetPlatform().SkinName(), GetPlatform().IsMultiSampled()),
       m_isHeadingEnabled(false),
-      m_isPositionEnabled(false)
+      m_isPositionEnabled(false),
+      m_isRedrawEnabled(true)
   {
     m_renderQueue.AddWindowHandle(m_windowHandle);
   }
@@ -223,6 +227,13 @@ public:
     UpdateNow();
   }
 
+  /// enabling/disabling AddRedrawCommand
+  void SetRedrawEnabled(bool isRedrawEnabled)
+  {
+    m_isRedrawEnabled = isRedrawEnabled;
+    AddRedrawCommand();
+  }
+
   /// respond to device orientation changes
   void SetOrientation(EOrientation orientation)
   {

qt/draw_widget.cpp

@@ -17,9 +17,12 @@ namespace qt
       m_handle(new handle_t(this)),
       m_framework(m_handle),
       m_isDrag(false),
-      m_pScale(0)
+      m_pScale(0),
+      m_redrawInterval(100)
   {
     m_framework.Init(storage);
+    m_timer = new QTimer(this);
+    connect(m_timer, SIGNAL(timeout()), this, SLOT(ScaleTimerElapsed()));
   }
 
   void DrawWidget::SetScaleControl(QSlider * pScale)
@@ -149,6 +152,7 @@ namespace qt
 
     if (e->button() == Qt::LeftButton)
     {
+      m_framework.SetRedrawEnabled(false);
       m_framework.StartDrag(get_drag_event(e));
 
       setCursor(Qt::CrossCursor);
@@ -163,6 +167,7 @@ namespace qt
     {
       if (m_isDrag)
       {
+        m_framework.SetRedrawEnabled(true);
         m_framework.StopDrag(get_drag_event(e));
         setCursor(Qt::ArrowCursor);
         m_isDrag = false;
@@ -186,6 +191,7 @@ namespace qt
 
     if (m_isDrag && e->button() == Qt::LeftButton)
     {
+      m_framework.SetRedrawEnabled(true);
       m_framework.StopDrag(get_drag_event(e));
 
       setCursor(Qt::ArrowCursor);
@@ -193,10 +199,22 @@ namespace qt
     }
   }
 
+  void DrawWidget::ScaleTimerElapsed()
+  {
+    m_framework.SetRedrawEnabled(true);
+    m_timer->stop();
+  }
+
   void DrawWidget::wheelEvent(QWheelEvent * e)
   {
     if (!m_isDrag)
     {
+      /// if we are inside the timer, cancel it
+      if (m_timer->isActive())
+        m_timer->stop();
+
+      m_framework.SetRedrawEnabled(false);
+      m_timer->start(m_redrawInterval);
       //m_framework.Scale(exp(e->delta() / 360.0));
 			m_framework.ScaleToPoint(ScaleToPointEvent(e->pos().x(), e->pos().y(), exp(e->delta() / 360.0)));
       UpdateScaleControl();

qt/draw_widget.hpp

@@ -7,6 +7,7 @@
 #include "../map/framework.hpp"
 #include "../map/navigator.hpp"
 
+#include <QtCore/QTimer>
 
 class FileReader;
 template <class> class ReaderSource;
@@ -35,6 +36,9 @@ namespace qt
 
     bool m_isDrag;
 
+    QTimer * m_timer;
+    size_t m_redrawInterval;
+
     Q_OBJECT
 
   public Q_SLOTS:
@@ -47,6 +51,7 @@ namespace qt
     void ShowAll();
     void Repaint();
     void ScaleChanged(int action);
+    void ScaleTimerElapsed();
 
   public:
     DrawWidget(QWidget * pParent, storage::Storage & storage);