text: /****************************************************************************
  **
  ** Copyright (C) 2016 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the QtQuick module of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:LGPL$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
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  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** GNU Lesser General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU Lesser
  ** General Public License version 3 as published by the Free Software
  ** Foundation and appearing in the file LICENSE.LGPL3 included in the
  ** packaging of this file. Please review the following information to
  ** ensure the GNU Lesser General Public License version 3 requirements
  ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
  **
  ** GNU General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU
  ** General Public License version 2.0 or (at your option) the GNU General
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  ** information to ensure the GNU General Public License requirements will
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  ****************************************************************************/
  
  #ifndef ITEMPARTICLE_H
  #define ITEMPARTICLE_H
  
  //
  //  W A R N I N G
  //  -------------
  //
  // This file is not part of the Qt API.  It exists purely as an
  // implementation detail.  This header file may change from version to
  // version without notice, or even be removed.
  //
  // We mean it.
  //
  #include "qquickparticlepainter_p.h"
  #include <QPointer>
  #include <QSet>
  #include <private/qquickanimation_p_p.h>
  QT_BEGIN_NAMESPACE
  
  class QQuickItemParticleAttached;
  
  class QQuickItemParticle : public QQuickParticlePainter
  {
      Q_OBJECT
      Q_PROPERTY(bool fade READ fade WRITE setFade NOTIFY fadeChanged)
      Q_PROPERTY(QQmlComponent* delegate READ delegate WRITE setDelegate NOTIFY delegateChanged)
  public:
      explicit QQuickItemParticle(QQuickItem *parent = 0);
      ~QQuickItemParticle();
  
      bool fade() const { return m_fade; }
  
      QSGNode *updatePaintNode(QSGNode *, UpdatePaintNodeData *) override;
  
      static QQuickItemParticleAttached *qmlAttachedProperties(QObject *object);
      QQmlComponent* delegate() const
      {
          return m_delegate;
      }
  
  Q_SIGNALS:
      void fadeChanged();
  
      void delegateChanged(QQmlComponent* arg);
  
  public Q_SLOTS:
      //TODO: Add a follow mode, where moving the delegate causes the logical particle to go with it?
      void freeze(QQuickItem* item);
      void unfreeze(QQuickItem* item);
      void take(QQuickItem* item,bool prioritize=false);//take by modelparticle
      void give(QQuickItem* item);//give from modelparticle
  
      void setFade(bool arg){if (arg == m_fade) return; m_fade = arg; Q_EMIT fadeChanged();}
      void setDelegate(QQmlComponent* arg)
      {
          if (m_delegate != arg) {
              m_delegate = arg;
              Q_EMIT delegateChanged(arg);
          }
      }
  
  protected:
      void reset() override;
      void commit(int gIdx, int pIdx) override;
      void initialize(int gIdx, int pIdx) override;
      void prepareNextFrame();
  private:
      void processDeletables();
      void tick(int time = 0);
      QSet<QQuickItem* > m_deletables;
      QList<QQuickItem* > m_managed;
      bool m_fade;
  
      QList<QQuickItem*> m_pendingItems;
      QList<int> m_available;
      QSet<QQuickItem*> m_stasis;
      qreal m_lastT;
      int m_activeCount;
      QQmlComponent* m_delegate;
  
      typedef QTickAnimationProxy<QQuickItemParticle, &QQuickItemParticle::tick> Clock;
      Clock *clock;
  };
  
  class QQuickItemParticleAttached : public QObject
  {
      Q_OBJECT
      Q_PROPERTY(QQuickItemParticle* particle READ particle CONSTANT);
  public:
      QQuickItemParticleAttached(QObject* parent)
          : QObject(parent), m_mp(0)
      {;}
      QQuickItemParticle* particle() const { return m_mp; }
      void detach(){Q_EMIT detached();}
      void attach(){Q_EMIT attached();}
  private:
      QQuickItemParticle* m_mp;
      friend class QQuickItemParticle;
  Q_SIGNALS:
      void detached();
      void attached();
  };
  
  QT_END_NAMESPACE
  
  QML_DECLARE_TYPEINFO(QQuickItemParticle, QML_HAS_ATTACHED_PROPERTIES)
  
  #endif // ITEMPARTICLE_H
  