File indexing completed on 2024-05-12 15:57:03

 /*
  *  SPDX-FileCopyrightText: 2021 Dmitry Kazakov <dimula73@gmail.com>
  *
  *  SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #ifndef KISRECTSGRID_H
 #define KISRECTSGRID_H
 
 #include <QRect>
 #include <QVector>
 #include "kritaglobal_export.h"
 
 
 /**
  * @brief A utility class to maintain a sparse grid of loaded/unloaded rects
  *
  * KisRectsGrid manages the presence of the rectangular cells in the grid
  * covering some specific area. The main usecase of the class is to maintain
  * an overlay device over another paint device.
  *
  * When you need to ensure that the overlay has some particular `rect` loaded,
  * you just call `grid->addRect(rect)` and get a list of rects that have not
  * yet been loaded into the overlay. The returned list may be empty if all the
  * grid cells intersecting `rect` has already been loaded (added to the grid).
  *
  * The size of the cell is defined at the construction stage and must be
  * power of 2.
  */
 class KRITAGLOBAL_EXPORT KisRectsGrid
 {
 public:
     /**
      * Create a grid with cell size set to \p gridSize
      */
     KisRectsGrid(int gridSize = 64);
 
 
     /**
      * Grow rectangle \p rc until it becomes aligned to
      * the grid cell borders.
      */
     QRect alignRect(const QRect &rc) const;
 
     /**
      * Add an arbitrary (non-aligned) rect to the grid
      *
      * The grid will form a list of cells that intersect \p rc and have not
      * not yet been loaded, mark them as loaded and return the list to the caller.
      *
      * \param rc the rect to be added, not necessary aligned to the grid
      * \return the list of cells that has actually been changed
      */
     QVector<QRect> addRect(const QRect &rc);
 
     /**
      * Remove an arbitrary (non-aligned) rect from the grid
      *
      * The grid will form a list of loaded cells that are fully contained in \p
      * rc, mark them as unloaded and return the list to the caller.
      *
      * TODO: please note that removing two neighbouring non-aligned rectangles
      * may still leave some cells marked as loaded. Perhaps we should change
      * the meaning of this function to remove "all intersecting rectangles"
      * instead of "all contained rectangles".
      *
      * \param rc the rect to be removed, not necessary aligned to the grid
      * \return the list of cells that has actually been changed
      */
     QVector<QRect> removeRect(const QRect &rc);
 
     /**
      * Add an aligned rect to the grid
      *
      * The grid will form a list of cells that intersect \p rc and have not
      * not yet been loaded, mark them as loaded and return the list to the caller.
      *
      * \param rc the rect to be added, the rect must be aligned
      * \return the list of cells that has actually been changed
      */
     QVector<QRect> addAlignedRect(const QRect &rc);
 
     /**
      * Remove an aligned rect from the grid
      *
      * The grid will form a list of loaded cells that are fully contained in \p
      * rc, mark them as unloaded and return the list to the caller.
      *
      * \param rc the rect to be removed, not necessary aligned to the grid
      * \return the list of cells that has actually been changed
      */
     QVector<QRect> removeAlignedRect(const QRect &rc);
 
     /**
      * Return is \p rc is fully covered by the loaded cells of the grid
      */
     bool contains(const QRect &rc) const;
 
     /**
      * Return the bounding box of the loaded cells of the grid
      */
     QRect boundingRect() const;
 
 private:
     void resize(const QRect &newMappedAreaSize);
     static QRect shrinkRectToAlignedGrid(const QRect &srcRect, int lod);
 
 private:
     int m_gridSize;
     int m_logGridSize;
     QVector<quint8> m_mapping;
     QRect m_mappedAreaSize; // measured in col/row
 
 };
 
 #endif // KISRECTSGRID_H