re-implemented resizable scrollbar (still somewhat crude)

app/widget/timebased/timebased.cpp

@@ -10,7 +10,8 @@ TimeBasedWidget::TimeBasedWidget(bool ruler_text_visible, bool ruler_cache_statu
   ruler_ = new TimeRuler(ruler_text_visible, ruler_cache_status_visible, this);
   connect(ruler_, &TimeRuler::TimeChanged, this, &TimeBasedWidget::SetTimeAndSignal);
 
-  scrollbar_ = new QScrollBar(Qt::Horizontal, this);
+  scrollbar_ = new ResizableScrollBar(Qt::Horizontal, this);
+  connect(scrollbar_, &ResizableScrollBar::RequestScale, this, &TimeBasedWidget::ScrollBarResized);
 }
 
 void TimeBasedWidget::SetScaleAndCenterOnPlayhead(const double &scale)
@@ -65,12 +66,17 @@ void TimeBasedWidget::UpdateMaximumScroll()
   scrollbar_->setMaximum(qMax(0, qCeil(TimeToScene(viewer_node_->Length())) - width()));
 }
 
+void TimeBasedWidget::ScrollBarResized(const double &multiplier)
+{
+  SetScale(GetScale() * multiplier);
+}
+
 TimeRuler *TimeBasedWidget::ruler() const
 {
   return ruler_;
 }
 
-QScrollBar *TimeBasedWidget::scrollbar() const
+ResizableScrollBar *TimeBasedWidget::scrollbar() const
 {
   return scrollbar_;
 }

app/widget/timebased/timebased.h

@@ -1,10 +1,10 @@
 #ifndef TIMEBASEDWIDGET_H
 #define TIMEBASEDWIDGET_H
 
-#include <QScrollBar>
 #include <QWidget>
 
 #include "node/output/viewer/viewer.h"
+#include "widget/resizablescrollbar/resizablescrollbar.h"
 #include "widget/timelinewidget/timelinescaledobject.h"
 #include "widget/timeruler/timeruler.h"
 
@@ -54,7 +54,7 @@ protected slots:
   void SetTimeAndSignal(const int64_t& t);
 
 protected:
-  QScrollBar* scrollbar() const;
+  ResizableScrollBar* scrollbar() const;
 
   virtual void TimebaseChangedEvent(const rational&) override;
 
@@ -88,13 +88,15 @@ private:
 
   TimeRuler* ruler_;
 
-  QScrollBar* scrollbar_;
+  ResizableScrollBar* scrollbar_;
 
   bool auto_max_scrollbar_;
 
 private slots:
   void UpdateMaximumScroll();
 
+  void ScrollBarResized(const double& multiplier);
+
 };
 
 #endif // TIMEBASEDWIDGET_H