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