navigator view draw viewport rect

navigatorview.cpp

@@ -1,9 +1,13 @@
 #include "navigatorview.h"
 
+#include "graphicsview.h"
+
 #include <QMouseEvent>
+#include <QDebug>
 
 NavigatorView::NavigatorView(QWidget *parent)
     : QGraphicsView (parent)
+    , m_viewportRegion(this->rect())
 {
     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
@@ -11,8 +15,31 @@ NavigatorView::NavigatorView(QWidget *parent)
                   "border-radius: 3px;");
 }
 
+// doesn't take or manage its ownership
+void NavigatorView::setMainView(GraphicsView *mainView)
+{
+    m_mainView = mainView;
+}
+
+void NavigatorView::updateMainViewportRegion()
+{
+    if (m_mainView != nullptr) {
+        m_viewportRegion = mapFromScene(m_mainView->mapToScene(m_mainView->rect()));
+        qDebug() << m_mainView->rect() << m_mainView->mapToScene(m_mainView->rect()) << m_viewportRegion;
+    }
+}
+
 void NavigatorView::wheelEvent(QWheelEvent *event)
 {
     event->ignore();
     return QGraphicsView::wheelEvent(event);
 }
+
+void NavigatorView::paintEvent(QPaintEvent *event)
+{
+    QGraphicsView::paintEvent(event);
+
+    QPainter painter(viewport());
+    painter.setPen(QPen(Qt::gray, 2));
+    painter.drawRect(m_viewportRegion.boundingRect());
+}