chore: adjusted the project directory structure

app/navigatorview.cpp

@@ -0,0 +1,80 @@
+#include "navigatorview.h"
+
+#include "graphicsview.h"
+#include "opacityhelper.h"
+
+#include <QMouseEvent>
+#include <QDebug>
+
+NavigatorView::NavigatorView(QWidget *parent)
+    : QGraphicsView (parent)
+    , m_viewportRegion(this->rect())
+    , m_opacityHelper(new OpacityHelper(this))
+{
+    setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    setStyleSheet("background-color: rgba(0, 0, 0, 120);"
+                  "border-radius: 3px;");
+}
+
+// doesn't take or manage its ownership
+void NavigatorView::setMainView(GraphicsView *mainView)
+{
+    m_mainView = mainView;
+}
+
+void NavigatorView::setOpacity(qreal opacity, bool animated)
+{
+    m_opacityHelper->setOpacity(opacity, animated);
+}
+
+void NavigatorView::updateMainViewportRegion()
+{
+    if (m_mainView != nullptr) {
+        m_viewportRegion = mapFromScene(m_mainView->mapToScene(m_mainView->rect()));
+    }
+}
+
+void NavigatorView::mousePressEvent(QMouseEvent *event)
+{
+    m_mouseDown = true;
+
+    if (m_mainView) {
+        m_mainView->centerOn(mapToScene(event->pos()));
+        update();
+    }
+
+    return QGraphicsView::mousePressEvent(event);
+}
+
+void NavigatorView::mouseMoveEvent(QMouseEvent *event)
+{
+    if (m_mouseDown && m_mainView) {
+        m_mainView->centerOn(mapToScene(event->pos()));
+        update();
+    }
+
+    return QGraphicsView::mouseMoveEvent(event);
+}
+
+void NavigatorView::mouseReleaseEvent(QMouseEvent *event)
+{
+    m_mouseDown = false;
+
+    return QGraphicsView::mouseReleaseEvent(event);
+}
+
+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());
+}