source: trunk/src/corelib/tools/qtimeline.cpp@ 45

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#include "qtimeline.h"

#include <private/qobject_p.h>
#include <QtCore/qdatetime.h>
#include <QtCore/qcoreevent.h>
#include <QtCore/qmath.h>

QT_BEGIN_NAMESPACE

static const qreal pi = qreal(3.14159265359);
static const qreal halfPi = pi / qreal(2.0);


static inline qreal qt_sinProgress(qreal value)
{
    return qSin((value * pi) - halfPi) / 2 + qreal(0.5);
}

static inline qreal qt_smoothBeginEndMixFactor(qreal value)
{
    return qMin(qMax(1 - value * 2 + qreal(0.3), qreal(0.0)), qreal(1.0));
}

class QTimeLinePrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QTimeLine)
public:
    inline QTimeLinePrivate()
        : startTime(0), duration(1000), startFrame(0), endFrame(0),
          updateInterval(1000 / 25),
          totalLoopCount(1), currentLoopCount(0), currentTime(0), timerId(0),
          direction(QTimeLine::Forward), curveShape(QTimeLine::EaseInOutCurve),
          state(QTimeLine::NotRunning)
    { }

    int startTime;
    int duration;
    int startFrame;
    int endFrame;
    int updateInterval;
    int totalLoopCount;
    int currentLoopCount;

    int currentTime;
    int elapsedTime;
    int timerId;
    QTime timer;

    QTimeLine::Direction direction;
    QTimeLine::CurveShape curveShape;
    QTimeLine::State state;
    inline void setState(QTimeLine::State newState)
    {
        Q_Q(QTimeLine);
        if (newState != state)
            emit q->stateChanged(state = newState);
    }

    void setCurrentTime(int msecs);
};

/*!
    \internal
*/
void QTimeLinePrivate::setCurrentTime(int msecs)
{
    Q_Q(QTimeLine);

    qreal lastValue = q->currentValue();
    int lastFrame = q->currentFrame();

    // Determine if we are looping.
    int elapsed = (direction == QTimeLine::Backward) ? (-msecs +  duration) : msecs;
    int loopCount = elapsed / duration;

    bool looping = (loopCount != currentLoopCount);
#ifdef QTIMELINE_DEBUG
    qDebug() << "QTimeLinePrivate::setCurrentTime:" << msecs << duration << "with loopCount" << loopCount
             << "currentLoopCount" << currentLoopCount
             << "looping" << looping;
#endif
    if (looping)
        currentLoopCount = loopCount;

    // Normalize msecs to be between 0 and duration, inclusive.
    currentTime = elapsed % duration;
    if (direction == QTimeLine::Backward)
        currentTime = duration - currentTime;

    // Check if we have reached the end of loopcount.
    bool finished = false;
    if (totalLoopCount && currentLoopCount >= totalLoopCount) {
        finished = true;
        currentTime = (direction == QTimeLine::Backward) ? 0 : duration;
        currentLoopCount = totalLoopCount - 1;
    }

    int currentFrame = q->frameForTime(currentTime);
#ifdef QTIMELINE_DEBUG
    qDebug() << "QTimeLinePrivate::setCurrentTime: frameForTime" << currentTime << currentFrame;
#endif
    if (lastValue != q->currentValue())
        emit q->valueChanged(q->currentValue());
    if (lastFrame != currentFrame) {
        const int transitionframe = (direction == QTimeLine::Forward ? endFrame : startFrame);
        if (looping && !finished && transitionframe != currentFrame) {
#ifdef QTIMELINE_DEBUG
            qDebug() << "QTimeLinePrivate::setCurrentTime: transitionframe";
#endif
            emit q->frameChanged(transitionframe);
        }
#ifdef QTIMELINE_DEBUG
        else {
            QByteArray reason;
            if (!looping)
                reason += " not looping";
            if (finished) {
                if (!reason.isEmpty())
                    reason += " and";
                reason += " finished";
            }
            if (transitionframe == currentFrame) {
                if (!reason.isEmpty())
                    reason += " and";
                reason += " transitionframe is equal to currentFrame: " + QByteArray::number(currentFrame);
            }
            qDebug("QTimeLinePrivate::setCurrentTime: not transitionframe because %s",  reason.constData());
        }
#endif
        emit q->frameChanged(currentFrame);
    }
    if (finished && state == QTimeLine::Running) {
        q->stop();
        emit q->finished();
    }
}

/*!
    \class QTimeLine
    \brief The QTimeLine class provides a timeline for controlling animations.
    \since 4.2
    \ingroup multimedia

    It's most commonly used to animate a GUI control by calling a slot
    periodically. You can construct a timeline by passing its duration in
    milliseconds to QTimeLine's constructor. The timeline's duration describes
    for how long the animation will run. Then you set a suitable frame range
    by calling setFrameRange(). Finally connect the frameChanged() signal to a
    suitable slot in the widget you wish to animate (e.g., setValue() in
    QProgressBar). When you proceed to calling start(), QTimeLine will enter
    Running state, and start emitting frameChanged() at regular intervals,
    causing your widget's connected property's value to grow from the lower
    end to the upper and of your frame range, at a steady rate. You can
    specify the update interval by calling setUpdateInterval(). When done,
    QTimeLine enters NotRunning state, and emits finished().

    Example:

    \snippet doc/src/snippets/code/src_corelib_tools_qtimeline.cpp 0

    You can also use QTimeLine with the
    \l{Graphics View}{Graphics View framework} for
    animations. The QGraphicsItemAnimation class implements animation
    of \l{QGraphicsItem}{QGraphicsItems} with a timeline.

    By default the timeline runs once, from the beginning and towards the end,
    upon which you must call start() again to restart from the beginning. To
    make the timeline loop, you can call setLoopCount(), passing the number of
    times the timeline should run before finishing. The direction can also be
    changed, causing the timeline to run backward, by calling
    setDirection(). You can also pause and unpause the timeline while it's
    running by calling setPaused(). For interactive control, the
    setCurrentTime() function is provided, which sets the time position of the
    time line directly. Although most useful in NotRunning state, (e.g.,
    connected to a valueChanged() signal in a QSlider,) this function can be
    called at any time.

    The frame interface is useful for standard widgets, but QTimeLine can be
    used to control any type of animation. The heart of QTimeLine lies in the
    valueForTime() function, which generates a \e value between 0 and 1 for a
    given time. This value is typically used to describe the steps of an
    animation, where 0 is the first step of an animation, and 1 is the last
    step. When running, QTimeLine generates values between 0 and 1 by calling
    valueForTime() and emitting valueChanged(). By default, valueForTime()
    applies an interpolation algorithm to generate these value. You can choose
    from a set of predefined timeline algorithms by calling
    setCurveShape(). By default, QTimeLine uses the EaseInOut curve shape,
    which provides a value that grows slowly, then grows steadily, and
    finally grows slowly. For a custom timeline, you can reimplement
    valueForTime(), in which case QTimeLine's curveShape property is ignored.

    \sa QProgressBar, QProgressDialog, QGraphicsItemAnimation
*/

/*!
    \enum QTimeLine::State

    This enum describes the state of the timeline.

    \value NotRunning The timeline is not running. This is the initial state
    of QTimeLine, and the state QTimeLine reenters when finished. The current
    time, frame and value remain unchanged until either setCurrentTime() is
    called, or the timeline is started by calling start().

    \value Paused The timeline is paused (i.e., temporarily
    suspended). Calling setPaused(false) will resume timeline activity.

    \value Running The timeline is running. While control is in the event
    loop, QTimeLine will update its current time at regular intervals,
    emitting valueChanged() and frameChanged() when appropriate.

    \sa state(), stateChanged()
*/

/*!
    \enum QTimeLine::Direction

    This enum describes the direction of the timeline when in \l Running state.

    \value Forward The current time of the timeline increases with time (i.e.,
    moves from 0 and towards the end / duration).

    \value Backward The current time of the timeline decreases with time (i.e.,
    moves from the end / duration and towards 0).

    \sa setDirection()
*/

/*!
    \enum QTimeLine::CurveShape

    This enum describes the default shape of QTimeLine's value curve. The
    default, shape is EaseInOutCurve. The curve defines the relation
    between the value and the timeline.

    \value EaseInCurve The value starts growing slowly, then increases in speed.
    \value EaseOutCurve The value starts growing steadily, then ends slowly.
    \value EaseInOutCurve The value starts growing slowly, then runs steadily, then grows slowly again.
    \value LinearCurve The value grows linearly (e.g., if the duration is 1000 ms,
           the value at time 500 ms is 0.5).
    \value SineCurve The value grows sinusoidally.
    \value CosineCurve The value grows cosinusoidally.

    \sa setCurveShape()
*/

/*!
    \fn QTimeLine::valueChanged(qreal value)

    QTimeLine emits this signal at regular intervals when in \l Running state,
    but only if the current value changes. \a value is the current value. \a value is
    a number between 0.0 and 1.0

    \sa QTimeLine::setDuration(), QTimeLine::valueForTime(), QTimeLine::updateInterval
*/

/*!
    \fn QTimeLine::frameChanged(int frame)

    QTimeLine emits this signal at regular intervals when in \l Running state,
    but only if the current frame changes. \a frame is the current frame number.

    \sa QTimeLine::setFrameRange(), QTimeLine::updateInterval
*/

/*!
    \fn QTimeLine::stateChanged(QTimeLine::State newState)

    This signal is emitted whenever QTimeLine's state changes. The new state
    is \a newState.
*/

/*!
    \fn QTimeLine::finished()

    This signal is emitted when QTimeLine finishes (i.e., reaches the end of
    its time line), and does not loop.
*/

/*!
    Constructs a timeline with a duration of \a duration milliseconds. \a
    parent is passed to QObject's constructor. The default duration is 1000
    milliseconds.
 */
QTimeLine::QTimeLine(int duration, QObject *parent)
    : QObject(*new QTimeLinePrivate, parent)
{
    setDuration(duration);
}

/*!
    Destroys the timeline.
 */
QTimeLine::~QTimeLine()
{
    Q_D(QTimeLine);

    if (d->state == Running)
        stop();
}

/*!
    Returns the state of the timeline.

    \sa start(), setPaused(), stop()
*/
QTimeLine::State QTimeLine::state() const
{
    Q_D(const QTimeLine);
    return d->state;
}

/*!
    \property QTimeLine::loopCount
    \brief the number of times the timeline should loop before it's finished.

    A loop count of of 0 means that the timeline will loop forever.

    By default, this property contains a value of 1.
*/
int QTimeLine::loopCount() const
{
    Q_D(const QTimeLine);
    return d->totalLoopCount;
}
void QTimeLine::setLoopCount(int count)
{
    Q_D(QTimeLine);
    d->totalLoopCount = count;
}

/*!
    \property QTimeLine::direction
    \brief the direction of the timeline when QTimeLine is in \l Running
    state.

    This direction indicates whether the time moves from 0 towards the
    timeline duration, or from the value of the duration and towards 0 after
    start() has been called.

    By default, this property is set to \l Forward.
*/
QTimeLine::Direction QTimeLine::direction() const
{
    Q_D(const QTimeLine);
    return d->direction;
}
void QTimeLine::setDirection(Direction direction)
{
    Q_D(QTimeLine);
    d->direction = direction;
    d->startTime = d->currentTime;
    d->timer.start();
}

/*!
    \property QTimeLine::duration
    \brief the total duration of the timeline in milliseconds.

    By default, this value is 1000 (i.e., 1 second), but you can change this
    by either passing a duration to QTimeLine's constructor, or by calling
    setDuration(). The duration must be larger than 0.
*/
int QTimeLine::duration() const
{
    Q_D(const QTimeLine);
    return d->duration;
}
void QTimeLine::setDuration(int duration)
{
    Q_D(QTimeLine);
    if (duration <= 0) {
        qWarning("QTimeLine::setDuration: cannot set duration <= 0");
        return;
    }
    d->duration = duration;
}

/*!
    Returns the start frame, which is the frame corresponding to the start of
    the timeline (i.e., the frame for which the current value is 0).

    \sa setStartFrame(), setFrameRange()
*/
int QTimeLine::startFrame() const
{