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/*
* SPDX-FileCopyrightText: 2011 Peter Penz <[email protected]>
*
* 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;
}
/**
* Set the bottom offset for moving the view so that the small overlayed statusbar
* won't cover any items by accident.
*/
void setStatusBarOffset(int offset);
#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;
int m_statusBarOffset;
friend class KItemListControllerTest;
};
#endif
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