flowlayout.h Example File

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 #include <QtWidgets/qgraphicslayout.h>

 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);

     int count() const;
     QGraphicsLayoutItem *itemAt(int index) const;
     void removeAt(int index);

 protected:
     QSizeF sizeHint(Qt::SizeHint which, const QSizeF &constraint = QSizeF()) const;

 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);
 }