Reduce connectivity for VMainGraphicsView class.

Use a signal instead of direct read of a main window to trigger zoom fit best.

src/app/valentina/mainwindow.cpp

@@ -504,6 +504,7 @@ void MainWindow::InitScenes()
 
     connect(ui->view, &VMainGraphicsView::MouseRelease, this, [this](){EndVisualization(true);});
     connect(ui->view, &VMainGraphicsView::ScaleChanged, this, &MainWindow::ScaleChanged);
+    connect(ui->view, &VMainGraphicsView::ZoomFitBestCurrent, this, [this](){ZoomFitBestCurrent();});
     QSizePolicy policy(QSizePolicy::Expanding, QSizePolicy::Expanding);
     policy.setHorizontalStretch(12);
     ui->view->setSizePolicy(policy);

src/libs/vwidgets/vmaingraphicsview.cpp

@@ -55,7 +55,7 @@
 #include "vmaingraphicsscene.h"
 #include "vsimplecurve.h"
 #include "vcontrolpointspline.h"
-#include "../vmisc/vabstractvalapplication.h"
+#include "../vmisc/vabstractapplication.h"
 #include "../vmisc/vcommonsettings.h"
 #include "vabstractmainwindow.h"
 #include "global.h"
@@ -645,10 +645,7 @@ void VMainGraphicsView::mouseDoubleClickEvent(QMouseEvent *event)
 {
     if (event->button() == Qt::LeftButton && qApp->Settings()->IsDoubleClickZoomFitBestCurrentPP())
     {
-        if (VAbstractMainWindow *window = qobject_cast<VAbstractMainWindow *>(qApp->getMainWindow()))
-        {
-            window->ZoomFitBestCurrent();
-        }
+        emit ZoomFitBestCurrent();
     }
 
     QGraphicsView::mouseDoubleClickEvent(event);

src/libs/vwidgets/vmaingraphicsview.h

@@ -149,6 +149,7 @@ signals:
     void     MouseRelease();
     void     itemClicked(QGraphicsItem *item);
     void     ScaleChanged(qreal scale);
+    void     ZoomFitBestCurrent();
 public slots:
     void     Zoom(qreal scale);
     void     ZoomIn();