revert: remove OpacityHelper

- remove OpacityHelper
- remove all related animation
- now bottom toolbar and navigation view are always visible

app/navigatorview.cpp

@@ -5,7 +5,6 @@
 #include "navigatorview.h"
 
 #include "graphicsview.h"
-#include "opacityhelper.h"
 
 #include <QMouseEvent>
 #include <QDebug>
@@ -14,7 +13,6 @@
 NavigatorView::NavigatorView(QWidget *parent)
     : QGraphicsView (parent)
     , m_viewportRegion(this->rect())
-    , m_opacityHelper(new OpacityHelper(this))
 {
     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
@@ -28,11 +26,6 @@ void NavigatorView::setMainView(GraphicsView *mainView)
     m_mainView = mainView;
 }
 
-void NavigatorView::setOpacity(qreal opacity, bool animated)
-{
-    m_opacityHelper->setOpacity(opacity, animated);
-}
-
 void NavigatorView::updateMainViewportRegion()
 {
     // Use QTimer::singleShot with lambda to delay the update