Change color of non selected items in QGraphicsScene/View

[d_stranz]

Connect a slot to the QGraphicsScene::selectionChanged() signal. In the slot, retrieve the QList of selected items QGraphicsScene::selectedItems(). Use that list to change the colors. If you keep a copy of the previous selections (initially empty), then you can change the colors only for the items that are not common to the old and new selection lists for better efficiency.