flowlayout.h Example File

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#include <QGraphicsLayout>
class FlowLayout : public QGraphicsLayout
{
public:
    FlowLayout();
    inline void addItem(QGraphicsLayoutItem *item);
    void insertItem(int index, QGraphicsLayoutItem *item);
    void setSpacing(Qt::Orientations o, qreal spacing);
    qreal spacing(Qt::Orientation o) const;
    // inherited functions
    void setGeometry(const QRectF &geom) override;
    int count() const override;
    QGraphicsLayoutItem *itemAt(int index) const override;
    void removeAt(int index) override;
protected:
    QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF()) const override;
private:
    qreal doLayout(const QRectF &geom, bool applyNewGeometry) const;
    QSizeF minSize(const QSizeF &constraint) const;
    QSizeF prefSize() const;
    QSizeF maxSize() const;
    QList<QGraphicsLayoutItem*> m_items;
    qreal m_spacing[2];
};
inline void FlowLayout::addItem(QGraphicsLayoutItem *item)
{
    insertItem(-1, item);
}