Render QGraphicsItem on QPixmap: aggregate 'QWidget w' has incomplete type and cannot be defined

Question

I would like to paint items into QPixmap without painting the scene...

I tried, based on this:

void Item::itemPaint(QPainter *painter)
{
    QStyleOptionGraphicsItem opt;
    QWidget w;
    paint(painter, &opt, &w);  // also tried NULL 
}

void Item::paint(QPainter *painter, const QStyleOptionGraphicsItem */*option*/, QWidget */*widget*/)
{
    ....
}


void caller()
{
    QPainter* painter;
    for(int i = 0; i< collectionView->scene()->items().size(); i++)
    {
        QGraphicsItem* qitem = collectionView->scene()->items().at(i);
        Item* item = new Item(*(dynamic_cast<Item*>(qitem)));
        QPixmap pItem(item->boundingRect().size().toSize());
        pItem.fill(QColor(Qt::color0).rgb());
        painter = new QPainter(&pItem);
        painter->setRenderHint(QPainter::Antialiasing);
        item->itemPaint(painter);
        painter->end();
    }
}

I get

error: aggregate 'QStyleOptionGraphicsItem opt' has incomplete type and cannot be defined
error: aggregate 'QWidget w' has incomplete type and cannot be defined

How can I use the item's paint method to render the single item only to a QPixmap ?

The alternative I think would be to create ANOTHER QGraphicsView on the item rectangle, and render that, but I think that would be too much overhead...

Answer 1

#include <QWidget> and #include <QStyleOptionGraphicsItem> should fix the compile error you are getting.