--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/declarative/util/qdeclarativesmoothedfollow.cpp	Tue Jul 06 15:10:48 2010 +0300
@@ -0,0 +1,299 @@
+/****************************************************************************
+**
+** Copyright (C) 2010 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.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the Technology Preview License Agreement accompanying
+** this package.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain additional
+** rights.  These rights are described in the Nokia Qt LGPL Exception
+** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
+**
+** If you have questions regarding the use of this file, please contact
+** Nokia at qt-info@nokia.com.
+**
+**
+**
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qdeclarativesmoothedfollow_p.h"
+#include "qdeclarativesmoothedanimation_p_p.h"
+
+#include <private/qobject_p.h>
+#include <QtCore/qnumeric.h>
+
+#include "qdeclarativeglobal_p.h"
+
+
+QT_BEGIN_NAMESPACE
+
+class QDeclarativeSmoothedFollowPrivate : public QObjectPrivate
+{
+    Q_DECLARE_PUBLIC(QDeclarativeSmoothedFollow)
+public:
+    QDeclarativeSmoothedFollowPrivate();
+
+    bool enabled;
+    QSmoothedAnimation *anim;
+};
+
+/*!
+    \qmlclass SmoothedFollow QDeclarativeSmoothedFollow
+    \since 4.7
+    \inherits NumberAnimation
+    \brief The SmoothedFollow element allows a property to smoothly track a value.
+
+    The SmoothedFollow animates a property's value to a set target value
+    using an ease in/out quad easing curve.  If the animation is restarted
+    with a different target value, the easing curves used to animate to the old
+    and the new target values are smoothly spliced together to avoid any obvious
+    visual glitches by maintaining the current velocity.
+
+    The property animation is configured by setting the velocity at which the
+    animation should occur, or the duration that the animation should take.
+    If both a velocity and a duration are specified, the one that results in
+    the quickest animation is chosen for each change in the target value.
+
+    For example, animating from 0 to 800 will take 4 seconds if a velocity
+    of 200 is set, will take 8 seconds with a duration of 8000 set, and will
+    take 4 seconds with both a velocity of 200 and a duration of 8000 set.
+    Animating from 0 to 20000 will take 10 seconds if a velocity of 200 is set,
+    will take 8 seconds with a duration of 8000 set, and will take 8 seconds
+    with both a velocity of 200 and a duration of 8000 set.
+
+    The follow example shows one rectangle tracking the position of another.
+\code
+import Qt 4.7
+
+Rectangle {
+    width: 800; height: 600; color: "blue"
+
+    Rectangle {
+        color: "green"
+        width: 60; height: 60;
+        SmoothedFollow on x { to: rect1.x - 5; velocity: 200 }
+        SmoothedFollow on y { to: rect1.y - 5; velocity: 200 }
+    }
+
+    Rectangle {
+        id: rect1
+        color: "red"
+        width: 50; height: 50;
+    }
+
+    focus: true
+    Keys.onRightPressed: rect1.x = rect1.x + 100
+    Keys.onLeftPressed: rect1.x = rect1.x - 100
+    Keys.onUpPressed: rect1.y = rect1.y - 100
+    Keys.onDownPressed: rect1.y = rect1.y + 100
+}
+\endcode
+
+    The default velocity of SmoothedFollow is 200 units/second.  Note that if the range of the
+    value being animated is small, then the velocity will need to be adjusted
+    appropriately.  For example, the opacity of an item ranges from 0 - 1.0.
+    To enable a smooth animation in this range the velocity will need to be
+    set to a value such as 0.5 units/second.  Animating from 0 to 1.0 with a velocity
+    of 0.5 will take 2000 ms to complete.
+
+    \sa SpringFollow
+*/
+
+QDeclarativeSmoothedFollow::QDeclarativeSmoothedFollow(QObject *parent)
+    : QObject(*(new QDeclarativeSmoothedFollowPrivate), parent)
+{
+}
+
+QDeclarativeSmoothedFollow::~QDeclarativeSmoothedFollow()
+{
+}
+
+QDeclarativeSmoothedFollowPrivate::QDeclarativeSmoothedFollowPrivate()
+    : enabled(true), anim(new QSmoothedAnimation)
+{
+    Q_Q(QDeclarativeSmoothedFollow);
+    QDeclarative_setParent_noEvent(anim, q);
+}
+
+/*!
+    \qmlproperty enumeration SmoothedFollow::reversingMode
+
+    Sets how the SmoothedFollow behaves if an animation direction is reversed.
+
+    If reversing mode is \c SmoothedFollow.Eased, the animation will smoothly decelerate, and
+    then reverse direction.  If the reversing mode is \c SmoothedFollow.Immediate, the
+    animation will immediately begin accelerating in the reverse direction,
+    begining with a velocity of 0.  If the reversing mode is \c SmoothedFollow.Sync, the
+    property is immediately set to the target value.
+*/
+QDeclarativeSmoothedFollow::ReversingMode QDeclarativeSmoothedFollow::reversingMode() const
+{
+    Q_D(const QDeclarativeSmoothedFollow);
+    return (ReversingMode) d->anim->reversingMode;
+}
+
+void QDeclarativeSmoothedFollow::setReversingMode(ReversingMode m)
+{
+    Q_D(QDeclarativeSmoothedFollow);
+    if (d->anim->reversingMode == (QDeclarativeSmoothedAnimation::ReversingMode) m)
+        return;
+
+    d->anim->reversingMode = (QDeclarativeSmoothedAnimation::ReversingMode) m;
+    emit reversingModeChanged();
+}
+
+/*!
+    \qmlproperty int SmoothedFollow::duration
+
+    This property holds the animation duration, in msecs, used when tracking the source.
+
+    Setting this to -1 (the default) disables the duration value.
+*/
+int QDeclarativeSmoothedFollow::duration() const
+{
+    Q_D(const QDeclarativeSmoothedFollow);
+    return d->anim->userDuration;
+}
+
+void QDeclarativeSmoothedFollow::setDuration(int duration)
+{
+    Q_D(QDeclarativeSmoothedFollow);
+    if (duration == d->anim->duration())
+        return;
+
+    d->anim->userDuration = duration;
+    emit durationChanged();
+}
+
+qreal QDeclarativeSmoothedFollow::velocity() const
+{
+    Q_D(const QDeclarativeSmoothedFollow);
+    return d->anim->velocity;
+}
+
+/*!
+    \qmlproperty real SmoothedFollow::velocity
+
+    This property holds the average velocity allowed when tracking the 'to' value.
+
+    The default velocity of SmoothedFollow is 200 units/second.
+
+    Setting this to -1 disables the velocity value.
+*/
+void QDeclarativeSmoothedFollow::setVelocity(qreal v)
+{
+    Q_D(QDeclarativeSmoothedFollow);
+    if (d->anim->velocity == v)
+        return;
+
+    d->anim->velocity = v;
+    emit velocityChanged();
+}
+
+/*!
+    \qmlproperty int SmoothedFollow::maximumEasingTime
+
+    This property specifies the maximum time, in msecs, an "eases" during the follow should take.
+    Setting this property causes the velocity to "level out" after at a time.  Setting
+    a negative value reverts to the normal mode of easing over the entire animation
+    duration.
+
+    The default value is -1.
+*/
+int QDeclarativeSmoothedFollow::maximumEasingTime() const
+{
+    Q_D(const QDeclarativeSmoothedFollow);
+    return d->anim->maximumEasingTime;
+}
+
+void QDeclarativeSmoothedFollow::setMaximumEasingTime(int v)
+{
+    Q_D(QDeclarativeSmoothedFollow);
+    d->anim->maximumEasingTime = v;
+    emit maximumEasingTimeChanged();
+}
+
+/*!
+    \qmlproperty real SmoothedFollow::to
+    This property holds the ending value.
+    If not set, then the value defined in the end state of the transition or Behavior.
+*/
+qreal QDeclarativeSmoothedFollow::to() const
+{
+    Q_D(const QDeclarativeSmoothedFollow);
+    return d->anim->to;
+}
+
+void QDeclarativeSmoothedFollow::setTo(qreal t)
+{
+    Q_D(QDeclarativeSmoothedFollow);
+
+    if (qIsNaN(t))
+        return;
+
+    if (d->anim->to == t)
+        return;
+
+    d->anim->to = t;
+
+    if (d->enabled)
+        d->anim->restart();
+}
+
+/*!
+    \qmlproperty bool SmoothedFollow::enabled
+    This property whether this animation should automatically restart when
+    the 'to' property is upated.
+
+    The default value of this property is 'true'.
+*/
+bool QDeclarativeSmoothedFollow::enabled() const
+{
+    Q_D(const QDeclarativeSmoothedFollow);
+    return d->enabled;
+}
+
+void QDeclarativeSmoothedFollow::setEnabled(bool e)
+{
+    Q_D(QDeclarativeSmoothedFollow);
+    if (d->enabled == e)
+        return;
+    d->enabled = e;
+
+    if (d->enabled)
+        d->anim->restart();
+    else
+        d->anim->stop();
+    emit enabledChanged();
+}
+
+void QDeclarativeSmoothedFollow::setTarget(const QDeclarativeProperty &t)
+{
+    Q_D(QDeclarativeSmoothedFollow);
+    d->anim->target = t;
+}
+
+QT_END_NAMESPACE