reimplemented zooming controls

app/widget/panel/panel.cpp

@@ -39,6 +39,14 @@ void PanelWidget::SetBorderVisible(bool enabled)
   update();
 }
 
+void PanelWidget::ZoomIn()
+{
+}
+
+void PanelWidget::ZoomOut()
+{
+}
+
 void PanelWidget::SetTitle(const QString &t)
 {
   title_ = t;

app/widget/panel/panel.h

@@ -46,6 +46,22 @@ public:
    * @param enabled
    */
   void SetBorderVisible(bool enabled);
+
+  /**
+   * @brief Called whenever this panel is focused and user uses "Zoom In" (either in menus or as a keyboard shortcut)
+   *
+   * This function is up to the Panel's interpretation of what the user intends to zoom into. Default behavior is a
+   * no-op.
+   */
+  virtual void ZoomIn();
+
+  /**
+   * @brief Called whenever this panel is focused and user uses "Zoom Out" (either in menus or as a keyboard shortcut)
+   *
+   * This function is up to the Panel's interpretation of what the user intends to zoom out of. Default behavior is a
+   * no-op.
+   */
+  virtual void ZoomOut();
 protected:
   /**
    * @brief Set panel's title

app/widget/timelineview/timelineview.cpp

@@ -98,7 +98,11 @@ void TimelineView::SetScale(const double &scale)
   QMapIterator<Block*, TimelineViewRect*> iterator(clip_items_);
 
   while (iterator.hasNext()) {
-    iterator.value()->SetScale(scale_);
+    iterator.next();
+
+    if (iterator.value() != nullptr) {
+      iterator.value()->SetScale(scale_);
+    }
   }
 
   playhead_line_->SetScale(scale_);

app/widget/timeruler/timeruler.cpp

@@ -69,7 +69,12 @@ void TimeRuler::SetTextVisible(bool e)
   update();
 }
 
-void TimeRuler::SetScale(double d)
+const double &TimeRuler::scale()
+{
+  return scale_;
+}
+
+void TimeRuler::SetScale(const double &d)
 {
   scale_ = d;
 

app/widget/timeruler/timeruler.h

@@ -35,7 +35,8 @@ public:
 
   void SetTextVisible(bool e);
 
-  void SetScale(double d);
+  const double& scale();
+  void SetScale(const double& d);
 
   void SetTimebase(const rational& r);
 

app/widget/viewer/viewer.cpp

@@ -67,6 +67,16 @@ void ViewerWidget::SetTimebase(const rational &r)
   controls_->SetTimebase(r);
 }
 
+const double &ViewerWidget::scale()
+{
+  return ruler_->scale();
+}
+
+void ViewerWidget::SetScale(const double &scale_)
+{
+  ruler_->SetScale(scale_);
+}
+
 void ViewerWidget::SetTexture(GLuint tex)
 {
   gl_widget_->SetTexture(tex);

app/widget/viewer/viewer.h

@@ -46,6 +46,10 @@ public:
 
   void SetTimebase(const rational& r);
 
+  const double& scale();
+
+  void SetScale(const double& scale_);
+
 public slots:
   /**
    * @brief Set the texture to draw and draw it