text: /****************************************************************************
  **
  ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
  ** All rights reserved.
  ** Contact: Nokia Corporation (qt-info@nokia.com)
  **
  ** This file is part of the QtDeclarative module of the Qt Toolkit.
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  ** GNU Lesser General Public License Usage
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  ** GNU General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU General
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  ****************************************************************************/
  
  #ifndef QDECLARATIVEFLICKABLE_P_H
  #define QDECLARATIVEFLICKABLE_P_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 "private/qdeclarativeflickable_p.h"
  
  #include "private/qdeclarativeitem_p.h"
  #include "private/qdeclarativeitemchangelistener_p.h"
  
  #include <qdeclarative.h>
  #include <qdeclarativetimeline_p_p.h>
  #include <qdeclarativeanimation_p_p.h>
  
  #include <qdatetime.h>
  #include "qplatformdefs.h"
  
  QT_BEGIN_NAMESPACE
  
  // Really slow flicks can be annoying.
  #ifndef QML_FLICK_MINVELOCITY
  #define QML_FLICK_MINVELOCITY 175
  #endif
  
  const qreal MinimumFlickVelocity = QML_FLICK_MINVELOCITY;
  
  class QDeclarativeFlickableVisibleArea;
  class QDeclarativeFlickablePrivate : public QDeclarativeItemPrivate, public QDeclarativeItemChangeListener
  {
      Q_DECLARE_PUBLIC(QDeclarativeFlickable)
  
  public:
      QDeclarativeFlickablePrivate();
      void init();
  
      struct Velocity : public QDeclarativeTimeLineValue
      {
          Velocity(QDeclarativeFlickablePrivate *p)
              : parent(p) {}
          virtual void setValue(qreal v) {
              if (v != value()) {
                  QDeclarativeTimeLineValue::setValue(v);
                  parent->updateVelocity();
              }
          }
          QDeclarativeFlickablePrivate *parent;
      };
  
      struct AxisData {
          AxisData(QDeclarativeFlickablePrivate *fp, void (QDeclarativeFlickablePrivate::*func)(qreal))
              : move(fp, func), viewSize(-1), smoothVelocity(fp), atEnd(false), atBeginning(true)
              , fixingUp(false), inOvershoot(false), moving(false), flicking(false)
          {}
  
          void reset() {
              velocityBuffer.clear();
              dragStartOffset = 0;
              fixingUp = false;
              inOvershoot = false;
          }
  
          void addVelocitySample(qreal v, qreal maxVelocity);
          void updateVelocity();
  
          QDeclarativeTimeLineValueProxy<QDeclarativeFlickablePrivate> move;
          qreal viewSize;
          qreal pressPos;
          qreal dragStartOffset;
          qreal dragMinBound;
          qreal dragMaxBound;
          qreal velocity;
          qreal flickTarget;
          QDeclarativeFlickablePrivate::Velocity smoothVelocity;
          QPODVector<qreal,10> velocityBuffer;
          bool atEnd : 1;
          bool atBeginning : 1;
          bool fixingUp : 1;
          bool inOvershoot : 1;
          bool moving : 1;
          bool flicking : 1;
      };
  
      void flickX(qreal velocity);
      void flickY(qreal velocity);
      virtual void flick(AxisData &data, qreal minExtent, qreal maxExtent, qreal vSize,
                          QDeclarativeTimeLineCallback::Callback fixupCallback, qreal velocity);
  
      void fixupX();
      void fixupY();
      virtual void fixup(AxisData &data, qreal minExtent, qreal maxExtent);
  
      void updateBeginningEnd();
  
      bool isOutermostPressDelay() const;
      void captureDelayedPress(QGraphicsSceneMouseEvent *event);
      void clearDelayedPress();
  
      void setRoundedViewportX(qreal x);
      void setRoundedViewportY(qreal y);
  
      qreal overShootDistance(qreal size);
  
      void itemGeometryChanged(QDeclarativeItem *, const QRectF &, const QRectF &);
  
  public:
      QDeclarativeItem *contentItem;
  
      AxisData hData;
      AxisData vData;
  
      QDeclarativeTimeLine timeline;
      bool hMoved : 1;
      bool vMoved : 1;
      bool stealMouse : 1;
      bool pressed : 1;
      bool interactive : 1;
      bool calcVelocity : 1;
      QElapsedTimer lastPosTime;
      QPointF lastPos;
      QPointF pressPos;
      QElapsedTimer pressTime;
      qreal deceleration;
      qreal maxVelocity;
      QElapsedTimer velocityTime;
      QPointF lastFlickablePosition;
      qreal reportedVelocitySmoothing;
      QGraphicsSceneMouseEvent *delayedPressEvent;
      QGraphicsItem *delayedPressTarget;
      QBasicTimer delayedPressTimer;
      int pressDelay;
      int fixupDuration;
  
      enum FixupMode { Normal, Immediate, ExtentChanged };
      FixupMode fixupMode;
  
      static void fixupY_callback(void *);
      static void fixupX_callback(void *);
  
      void updateVelocity();
      int vTime;
      QDeclarativeTimeLine velocityTimeline;
      QDeclarativeFlickableVisibleArea *visibleArea;
      QDeclarativeFlickable::FlickableDirection flickableDirection;
      QDeclarativeFlickable::BoundsBehavior boundsBehavior;
  
      void handleMousePressEvent(QGraphicsSceneMouseEvent *);
      void handleMouseMoveEvent(QGraphicsSceneMouseEvent *);
      void handleMouseReleaseEvent(QGraphicsSceneMouseEvent *);
  
      // flickableData property
      static void data_append(QDeclarativeListProperty<QObject> *, QObject *);
      static int data_count(QDeclarativeListProperty<QObject> *);
      static QObject *data_at(QDeclarativeListProperty<QObject> *, int);
      static void data_clear(QDeclarativeListProperty<QObject> *);
  };
  
  class QDeclarativeFlickableVisibleArea : public QObject
  {
      Q_OBJECT
  
      Q_PROPERTY(qreal xPosition READ xPosition NOTIFY xPositionChanged)
      Q_PROPERTY(qreal yPosition READ yPosition NOTIFY yPositionChanged)
      Q_PROPERTY(qreal widthRatio READ widthRatio NOTIFY widthRatioChanged)
      Q_PROPERTY(qreal heightRatio READ heightRatio NOTIFY heightRatioChanged)
  
  public:
      QDeclarativeFlickableVisibleArea(QDeclarativeFlickable *parent=0);
  
      qreal xPosition() const;
      qreal widthRatio() const;
      qreal yPosition() const;
      qreal heightRatio() const;
  
      void updateVisible();
  
  signals:
      void xPositionChanged(qreal xPosition);
      void yPositionChanged(qreal yPosition);
      void widthRatioChanged(qreal widthRatio);
      void heightRatioChanged(qreal heightRatio);
  
  private:
      QDeclarativeFlickable *flickable;
      qreal m_xPosition;
      qreal m_widthRatio;
      qreal m_yPosition;
      qreal m_heightRatio;
  };
  
  QT_END_NAMESPACE
  
  QML_DECLARE_TYPE(QDeclarativeFlickableVisibleArea)
  
  #endif
  