File indexing completed on 2024-05-19 05:32:28

 /*
     SPDX-FileCopyrightText: 2022 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
 
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #pragma once
 
 #include "kwin_export.h"
 
 #include <QList>
 #include <QRegion>
 
 namespace KWin
 {
 
 /**
  * The DamageJournal class is a helper that tracks last N damage regions.
  */
 class KWIN_EXPORT DamageJournal
 {
 public:
     /**
      * Returns the maximum number of damage regions that can be stored in the journal.
      */
     int capacity() const
     {
         return m_capacity;
     }
 
     /**
      * Sets the maximum number of damage regions that can be stored in the journal
      * to @a capacity.
      */
     void setCapacity(int capacity)
     {
         m_capacity = capacity;
     }
 
     /**
      * Adds the specified @a region to the journal.
      */
     void add(const QRegion &region)
     {
         while (m_log.size() >= m_capacity) {
             m_log.takeLast();
         }
         m_log.prepend(region);
     }
 
     /**
      * Clears the damage journal. Typically, one would want to clear the damage journal
      * if a buffer swap fails for some reason.
      */
     void clear()
     {
         m_log.clear();
     }
 
     /**
      * Accumulates the damage regions in the log up to the specified @a bufferAge.
      *
      * If the specified buffer age value refers to a damage region older than the last
      * one in the journal, @a fallback will be returned.
      */
     QRegion accumulate(int bufferAge, const QRegion &fallback = QRegion()) const
     {
         QRegion region;
         if (bufferAge > 0 && bufferAge <= m_log.size()) {
             for (int i = 0; i < bufferAge - 1; ++i) {
                 region += m_log[i];
             }
         } else {
             region = fallback;
         }
         return region;
     }
 
     QRegion lastDamage() const
     {
         return m_log.first();
     }
 
 private:
     QList<QRegion> m_log;
     int m_capacity = 10;
 };
 
 } // namespace KWin