File indexing completed on 2024-05-12 05:47:31

 /*
  * SPDX-FileCopyrightText: 2011 Peter Penz <peter.penz19@gmail.com>
  *
  * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #ifndef KITEMLISTVIEWLAYOUTER_H
 #define KITEMLISTVIEWLAYOUTER_H
 
 #include "dolphin_export.h"
 
 #include <QObject>
 #include <QRectF>
 #include <QSet>
 #include <QSizeF>
 #include <QVector>
 
 class KItemModelBase;
 class KItemListSizeHintResolver;
 
 /**
  * @brief Internal helper class for KItemListView to layout the items.
  *
  * The layouter is capable to align the items within a grid. If the
  * scroll-direction is horizontal the column-width of the grid can be
  * variable. If the scroll-direction is vertical the row-height of
  * the grid can be variable.
  *
  * The layouter is implemented in a way that it postpones the expensive
  * layout operation until a property is read the first time after
  * marking the layouter as dirty (see markAsDirty()). This means that
  * changing properties of the layouter is not expensive, only the
  * first read of a property can get expensive.
  */
 class DOLPHIN_EXPORT KItemListViewLayouter : public QObject
 {
     Q_OBJECT
 
 public:
     explicit KItemListViewLayouter(KItemListSizeHintResolver *sizeHintResolver, QObject *parent = nullptr);
     ~KItemListViewLayouter() override;
 
     void setScrollOrientation(Qt::Orientation orientation);
     Qt::Orientation scrollOrientation() const;
 
     void setSize(const QSizeF &size);
     QSizeF size() const;
 
     void setItemSize(const QSizeF &size);
     QSizeF itemSize() const;
 
     /**
      * Margin between the rows and columns of items.
      */
     void setItemMargin(const QSizeF &margin);
     QSizeF itemMargin() const;
 
     /**
      * Sets the height of the header that is always aligned
      * at the top. A height of <= 0.0 means that no header is
      * used.
      */
     void setHeaderHeight(qreal height);
     qreal headerHeight() const;
 
     /**
      * Sets the height of the group header that is used
      * to indicate a new item group.
      */
     void setGroupHeaderHeight(qreal height);
     qreal groupHeaderHeight() const;
 
     /**
      * Sets the margin between the last items of the group n and
      * the group header for the group n + 1.
      */
     void setGroupHeaderMargin(qreal margin);
     qreal groupHeaderMargin() const;
 
     void setScrollOffset(qreal scrollOffset);
     qreal scrollOffset() const;
 
     qreal maximumScrollOffset() const;
 
     void setItemOffset(qreal scrollOffset);
     qreal itemOffset() const;
 
     qreal maximumItemOffset() const;
 
     void setModel(const KItemModelBase *model);
     const KItemModelBase *model() const;
 
     /**
      * @return The first (at least partly) visible index. -1 is returned
      *         if the item count is 0.
      */
     int firstVisibleIndex() const;
 
     /**
      * @return The last (at least partly) visible index. -1 is returned
      *         if the item count is 0.
      */
     int lastVisibleIndex() const;
 
     /**
      * @return Rectangle of the item with the index \a index.
      *         The top/left of the bounding rectangle is related to
      *         the top/left of the KItemListView. An empty rectangle
      *         is returned if an invalid index is given.
      */
     QRectF itemRect(int index) const;
 
     /**
      * @return Rectangle of the group header for the item with the
      *         index \a index. Note that the layouter does not check
      *         whether the item really has a header: Usually only
      *         the first item of a group gets a header (see
      *         isFirstGroupItem()).
      */
     QRectF groupHeaderRect(int index) const;
 
     /**
      * @return Column of the item with the index \a index.
      *         -1 is returned if an invalid index is given.
      */
     int itemColumn(int index) const;
 
     /**
      * @return Row of the item with the index \a index.
      *         -1 is returned if an invalid index is given.
      */
     int itemRow(int index) const;
 
     /**
      * @return Maximum number of (at least partly) visible items for
      *         the given size.
      */
     int maximumVisibleItems() const;
 
     /**
      * @return True if the item with the index \p itemIndex
      *         is the first item within a group.
      */
     bool isFirstGroupItem(int itemIndex) const;
 
     /**
      * Marks the layouter as dirty. This means as soon as a property of
      * the layouter gets read, an expensive relayout will be done.
      */
     void markAsDirty();
 
     inline int columnCount() const
     {
         return m_columnCount;
     }
 
 #ifndef QT_NO_DEBUG
     /**
      * @return True if the layouter has been marked as dirty and hence has
      *         not called yet doLayout(). Is enabled only in the debugging
      *         mode, as it is not useful to check the dirty state otherwise.
      */
     bool isDirty();
 #endif
 
 private:
     void doLayout();
     void updateVisibleIndexes();
     bool createGroupHeaders();
 
     /**
      * @return Minimum width of group headers when grouping is enabled in the horizontal
      *         alignment mode. The header alignment is done like this:
      *         Header-1 Header-2 Header-3
      *         Item 1   Item 4   Item 7
      *         Item 2   Item 5   Item 8
      *         Item 3   Item 6   Item 9
      */
     qreal minimumGroupHeaderWidth() const;
 
 private:
     bool m_dirty;
     bool m_visibleIndexesDirty;
 
     Qt::Orientation m_scrollOrientation;
     QSizeF m_size;
 
     QSizeF m_itemSize;
     QSizeF m_itemMargin;
     qreal m_headerHeight;
     const KItemModelBase *m_model;
     KItemListSizeHintResolver *m_sizeHintResolver;
 
     qreal m_scrollOffset;
     qreal m_maximumScrollOffset;
 
     qreal m_itemOffset;
     qreal m_maximumItemOffset;
 
     int m_firstVisibleIndex;
     int m_lastVisibleIndex;
 
     qreal m_columnWidth;
     qreal m_xPosInc;
     int m_columnCount;
 
     QVector<qreal> m_rowOffsets;
     QVector<qreal> m_columnOffsets;
 
     // Stores all item indexes that are the first item of a group.
     // Assures fast access for KItemListViewLayouter::isFirstGroupItem().
     QSet<int> m_groupItemIndexes;
     qreal m_groupHeaderHeight;
     qreal m_groupHeaderMargin;
 
     struct ItemInfo {
         int column;
         int row;
     };
     QVector<ItemInfo> m_itemInfos;
 
     friend class KItemListControllerTest;
 };
 
 #endif