可以使用QGraphicsPixmapItem::setShapeMode()與任何QGraphicsPixmapItem::MaskShape
或QGraphicsPixmapItem::HeuristicMaskShape
此:
#include <QtGui>
#include <QtWidgets>
class Item : public QGraphicsPixmapItem
{
public:
Item() {
setShapeMode(QGraphicsPixmapItem::MaskShape);
QPixmap pixmap(100, 100);
pixmap.fill(Qt::transparent);
QPainter painter(&pixmap);
painter.setBrush(Qt::gray);
painter.setPen(Qt::NoPen);
painter.drawEllipse(0, 0, 100 - painter.pen().width(), 100 - painter.pen().width());
setPixmap(pixmap);
}
enum { Type = QGraphicsItem::UserType };
int type() const {
return Type;
}
};
int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QGraphicsView view;
view.setScene(new QGraphicsScene());
Item *item = new Item();
view.scene()->addItem(item);
// Comment out to see the item.
QGraphicsPathItem *shapeItem = view.scene()->addPath(item->shape());
shapeItem->setBrush(Qt::red);
shapeItem->setPen(Qt::NoPen);
view.show();
return app.exec();
}