added basic ghost functionality

app/widget/timelineview/timelineviewclipitem.cpp

@@ -21,12 +21,15 @@
 #include "timelineviewclipitem.h"
 
 #include <QBrush>
+#include <QGraphicsScene>
+#include <QGraphicsSceneMouseEvent>
 #include <QPainter>
 #include <QStyleOptionGraphicsItem>
 
 TimelineViewClipItem::TimelineViewClipItem(QGraphicsItem* parent) :
   QGraphicsRectItem(parent),
-  clip_(nullptr)
+  clip_(nullptr),
+  ghost_(nullptr)
 {
   setBrush(Qt::white);
   setFlag(QGraphicsItem::ItemIsSelectable, true);
@@ -61,3 +64,32 @@ void TimelineViewClipItem::paint(QPainter *painter, const QStyleOptionGraphicsIt
   painter->drawLine(QPointF(rect().left(), rect().bottom() - 1), QPointF(rect().right(), rect().bottom() - 1));
   painter->drawLine(QPointF(rect().right(), rect().bottom() - 1), QPointF(rect().right(), rect().top()));
 }
+
+void TimelineViewClipItem::mousePressEvent(QGraphicsSceneMouseEvent *event)
+{
+  QGraphicsRectItem::mousePressEvent(event);
+
+  ghost_ = new TimelineViewGhostItem();
+  ghost_->setRect(rect());
+  scene()->addItem(ghost_);
+}
+
+void TimelineViewClipItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
+{
+  QGraphicsRectItem::mouseMoveEvent(event);
+
+  if (ghost_ != nullptr) {
+    ghost_->setPos(event->scenePos());
+  }
+}
+
+void TimelineViewClipItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
+{
+  QGraphicsRectItem::mouseReleaseEvent(event);
+
+  if (ghost_ != nullptr) {
+    scene()->removeItem(ghost_);
+    delete ghost_;
+    ghost_ = nullptr;
+  }
+}

app/widget/timelineview/timelineviewclipitem.h

@@ -24,6 +24,7 @@
 #include <QGraphicsRectItem>
 
 #include "node/block/clip/clip.h"
+#include "timelineviewghostitem.h"
 
 class TimelineViewClipItem : public QGraphicsRectItem
 {
@@ -35,8 +36,14 @@ public:
 protected:
   virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = nullptr) override;
 
+  virtual void mousePressEvent(QGraphicsSceneMouseEvent *event) override;
+  virtual void mouseMoveEvent(QGraphicsSceneMouseEvent *event) override;
+  virtual void mouseReleaseEvent(QGraphicsSceneMouseEvent *event) override;
+
 private:
   ClipBlock* clip_;
+
+  TimelineViewGhostItem* ghost_;
 };
 
 #endif // TIMELINEVIEWCLIPITEM_H