Added tooltip event triggers for info messages

src/GUI/graphicsscene.h

@@ -0,0 +1,36 @@
+#ifndef GRAPHICSSCENE_H
+#define GRAPHICSSCENE_H
+
+#include <QGraphicsScene>
+#include <QGraphicsItem>
+#include <QGraphicsSceneHelpEvent>
+#include <QWidget>
+#include "popup.h"
+
+class GraphicsItem : public QGraphicsItem
+{
+public:
+	GraphicsItem(QGraphicsItem *parent = 0) : QGraphicsItem(parent) {}
+
+	virtual QString info() const = 0;
+	int type() const {return QGraphicsItem::UserType + 1;}
+};
+
+class GraphicsScene : public QGraphicsScene
+{
+public:
+	GraphicsScene(QObject *parent = 0) : QGraphicsScene(parent) {}
+
+protected:
+	void helpEvent(QGraphicsSceneHelpEvent *event)
+	{
+		QGraphicsItem *item = itemAt(event->scenePos(), QTransform());
+		if (item && item->type() == QGraphicsItem::UserType + 1) {
+			GraphicsItem *mi = static_cast<GraphicsItem*>(item);
+			Popup::show(event->screenPos(), mi->info(),
+			  static_cast<QWidget*>(parent()));
+		}
+	}
+};
+
+#endif // GRAPHICSSCENE_H