Easiest way to animate QGraphicsPixmapItem?

Question

I want to animate a QGraphicsPixmapItem in my QGraphicsScene, with QPropertyAnimation.

QPixmap pixmap(filePath);
QGraphicsItem *pixmapItem = graphicsScene->addPixmap(pixmap);

QPropertyAnimation animation(pixmapItem, "x"); // here lies the problem
animation.setDuration(30000);
// ...
animation.start();

I checked the doc, so I already know that QGraphicsPixmapItem and its parent QGraphicsItem are no QObject, and that a QPropertyAnimation constructor with a QGraphicsItem does not exist. According to various sources, the best way is to create a new class, e.g. AnimatedGraphicsItem which inherits from QObject and QGraphicsItem OR I can simply inherit from QGraphicsObject.

class AnimatedGraphicsItem : public QObject, public QGraphicsItem // or public QGraphicsObject
{
    Q_OBJECT
    Q_INTERFACES(QGraphicsItem) // not needed if I inherit from QGraphicsObject, right?
};

What do I need to include exactly in the header and source files of my AnimatedGraphicsItem class? One source told me to include this in the header file too, but I thought, this is already inherited?

public:
    AnimatedGraphicsItem(QGraphicsItem *parent = 0);

private:
     virtual QRectF boundingRect() const;
     virtual void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);

And how do I have to use my AnimatedGraphicsItem class?

Do I have to cast my QGraphicsItem *pixmapItem to AnimatedGraphicsItem? (If yes, how?) Do I have to create a new instance of AnimatedGraphicsItem?

I haven't found a good example on the Internet.

Thanks in advance!

Answer 1

Okay, got it.

I had to instantiate my AnimatedGraphicsItem object, then setPixmap, setFlag, … and addItem to my scene (and it was important to use new).