qmovie.cpp

奇趣公司比较新的qt/emd版本

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/*! 
    \class QMovie

    \brief The QMovie class is a convenience class for playing movies
    with QImageReader.

    \ingroup multimedia

    First, create a QMovie object by passing either the name of a file or a
    pointer to a QIODevice containing an animated image format to QMovie's
    constructor. You can call isValid() to check if the image data is valid,
    before starting the movie. To start the movie, call start(). QMovie will
    enter \l Running state, and emit started() and stateChanged(). To get the
    current state of the movie, call state().

    To display the movie in your application, you can pass your QMovie object
    to QLabel::setMovie(). Example:

    \code
        QLabel label;
        QMovie *movie = new QMovie("animations/fire.gif");

        label.setMovie(movie);
        movie->start();
    \endcode

    Whenever a new frame is available in the movie, QMovie will emit
    updated(). If the size of the frame changes, resized() is emitted. You can
    call currentImage() or currentPixmap() to get a copy of the current
    frame. When the movie is done, QMovie emits finished(). If any error
    occurs during playback (i.e, the image file is corrupt), QMovie will emit
    error().

    You can control the speed of the movie playback by calling setSpeed(),
    which takes the percentage of the original speed as an argument. Pause the
    movie by calling setPaused(true). QMovie will then enter \l Paused state
    and emit stateChanged(). If you call setPaused(false), QMovie will reenter
    \l Running state and start the movie again. To stop the movie, call
    stop().

    Certain animation formats allow you to set the background color. You can
    call setBackgroundColor() to set the color, or backgroundColor() to
    retrieve the current background color.

    currentFrameNumber() returns the sequence number of the current frame. The
    first frame in the animation has the sequence number 0. frameCount()
    returns the total number of frames in the animation, if the image format
    supports this. You can call loopCount() to get the number of times the
    movie should loop before finishing. nextFrameDelay() returns the number of
    milliseconds the current frame should be displayed.

    QMovie can be instructed to cache frames of an animation by calling
    setCacheMode().

    Call supportedFormats() for a list of formats that QMovie supports.

    \sa QLabel, QImageReader, {Movie Example}
*/

/*! \enum QMovie::MovieState

    This enum describes the different states of QMovie.

    \value NotRunning The movie is not running. This is QMovie's initial
    state, and the state it enters after stop() has been called or the movie
    is finished.

    \value Paused The movie is paused, and QMovie stops emitting updated() or
    resized(). This state is entered after calling pause() or
    setPaused(true). The current frame number it kept, and the movie will
    continue with the next frame when unpause() or setPaused(false) is called.

    \value Running The movie is running.
*/

/*! \enum QMovie::CacheMode

    This enum describes the different cache modes of QMovie.

    \value CacheNone No frames are cached (the default).

    \value CacheAll All frames are cached.
*/

/*! \fn void QMovie::started()

    This signal is emitted after QMovie::start() has been called, and QMovie
    has entered QMovie::Running state.
*/

/*! \fn void QMovie::resized(const QSize &size)

    This signal is emitted when the current frame has been resized to \a
    size. This effect is sometimes used in animations as an alternative to
    replacing the frame. You can call currentImage() or currentPixmap() to get a
    copy of the updated frame.
*/

/*! \fn void QMovie::updated(const QRect &rect)

    This signal is emitted when the rect \a rect in the current frame has been
    updated. You can call currentImage() or currentPixmap() to get a copy of the
    updated frame.
*/

/*! \fn void QMovie::frameChanged(int frameNumber)
    \since 4.1

    This signal is emitted when the frame number has changed to
    \a frameNumber.  You can call currentImage() or currentPixmap() to get a
    copy of the frame.
*/

/*! 
    \fn void QMovie::stateChanged(QMovie::MovieState state)

    This signal is emitted every time the state of the movie changes. The new
    state is specified by \a state.

    \sa QMovie::state()
*/

/*! \fn void QMovie::error(QImageReader::ImageReaderError error)

    This signal is emitted by QMovie when the error \a error occurred during
    playback.  QMovie will stop the movie, and enter QMovie::NotRunning state.
*/

/*! \fn void QMovie::finished()

    This signal is emitted when the movie has finished.

    \sa QMovie::stop()
*/

#include "qglobal.h"

#ifndef QT_NO_MOVIE

#include "qmovie.h"
#include "qimage.h"
#include "qimagereader.h"
#include "qpixmap.h"
#include "qrect.h"
#include "qdatetime.h"
#include "qtimer.h"
#include "qpair.h"
#include "qmap.h"
#include "qlist.h"
#include "qbuffer.h"
#include "private/qobject_p.h"

#define QMOVIE_INVALID_DELAY -1

class QFrameInfo
{
public:
    QPixmap pixmap;
    int delay;
    bool endMark;
    inline QFrameInfo(bool endMark)
        : pixmap(QPixmap()), delay(QMOVIE_INVALID_DELAY), endMark(endMark)
    { }
    
    inline QFrameInfo()
        : pixmap(QPixmap()), delay(QMOVIE_INVALID_DELAY), endMark(false)
    { }
    
    inline QFrameInfo(const QPixmap &pixmap, int delay)
        : pixmap(pixmap), delay(delay), endMark(false)
    { }
    
    inline bool isValid()
    {
        return endMark || !(pixmap.isNull() && (delay == QMOVIE_INVALID_DELAY));
    }
    
    inline bool isEndMarker()
    { return endMark; }
    
    static inline QFrameInfo endMarker()
    { return QFrameInfo(true); }
};

class QMoviePrivate : public QObjectPrivate
{
    Q_DECLARE_PUBLIC(QMovie)

public:
    QMoviePrivate(QMovie *qq);
    bool isDone();
    bool next();
    int speedAdjustedDelay(int delay) const;
    bool isValid() const;
    bool jumpToFrame(int frameNumber);
    int frameCount() const;
    bool jumpToNextFrame();
    QFrameInfo infoForFrame(int frameNumber);
    void reset();

    inline void enterState(QMovie::MovieState newState) {
        movieState = newState;
        emit q_func()->stateChanged(newState);
    }

    // private slots
    void _q_loadNextFrame();
    void _q_loadNextFrame(bool starting);

    QImageReader *reader;
    int speed;
    QMovie::MovieState movieState;
    QRect frameRect;
    QPixmap currentPixmap;
    int currentFrameNumber;
    int nextFrameNumber;
    int greatestFrameNumber;
    int nextDelay;
    int playCounter;
    qint64 initialDevicePos;
    QMovie::CacheMode cacheMode;
    bool haveReadAll;
    bool isFirstIteration;
    QMap<int, QFrameInfo> frameMap;

    QTimer nextImageTimer;
};

/*! \internal
 */
QMoviePrivate::QMoviePrivate(QMovie *qq)
    : reader(0), speed(100), movieState(QMovie::NotRunning),
      currentFrameNumber(-1), nextFrameNumber(0), greatestFrameNumber(-1),
      nextDelay(0), playCounter(-1),
      cacheMode(QMovie::CacheNone), haveReadAll(false), isFirstIteration(true)
{
    q_ptr = qq;
    nextImageTimer.setSingleShot(true);
}

/*! \internal
 */
void QMoviePrivate::reset()
{
    nextImageTimer.stop();
    if (reader->device())
        initialDevicePos = reader->device()->pos();
    currentFrameNumber = -1;
    nextFrameNumber = 0;
    greatestFrameNumber = -1;
    nextDelay = 0;
    playCounter = -1;
    haveReadAll = false;
    isFirstIteration = true;
    frameMap.clear();
}

/*! \internal
 */
bool QMoviePrivate::isDone()
{
    return (playCounter == 0);
}

/*!
    \internal

    Given the original \a delay, this function returns the
    actual number of milliseconds to delay according to
    the current speed. E.g. if the speed is 200%, the
    result will be half of the original delay.
*/
int QMoviePrivate::speedAdjustedDelay(int delay) const
{
    return int( (qint64(delay) * qint64(100) ) / qint64(speed) );
}

/*!
    \internal

    Returns the QFrameInfo for the given \a frameNumber.

    If the frame number is invalid, an invalid QFrameInfo is
    returned.

    If the end of the animation has been reached, a
    special end marker QFrameInfo is returned.

*/
QFrameInfo QMoviePrivate::infoForFrame(int frameNumber)
{
    if (frameNumber < 0)
        return QFrameInfo(); // Invalid

    if (haveReadAll && (frameNumber > greatestFrameNumber)) {
        if (frameNumber == greatestFrameNumber+1)
            return QFrameInfo::endMarker();
        return QFrameInfo(); // Invalid
    }

    if (cacheMode == QMovie::CacheNone) {
        if (frameNumber != currentFrameNumber+1) {
            // Non-sequential frame access
            if (!reader->jumpToImage(frameNumber)) {
                if (frameNumber == 0) {
                    // Special case: Attempt to "rewind" so we can loop
                    // ### This could be implemented as QImageReader::rewind()
                    if (reader->device()->isSequential())
                        return QFrameInfo(); // Invalid
                    QString fileName = reader->fileName();
                    QByteArray format = reader->format();
                    QIODevice *device = reader->device();
                    QColor bgColor = reader->backgroundColor();
                    QSize scaledSize = reader->scaledSize();
                    delete reader;
                    if (fileName.isEmpty())
                        reader = new QImageReader(device, format);
                    else
                        reader = new QImageReader(fileName, format);
                    reader->canRead(); // Provoke a device->open() call
                    reader->device()->seek(initialDevicePos);
                    reader->setBackgroundColor(bgColor);
                    reader->setScaledSize(scaledSize);
                } else {
                    return QFrameInfo(); // Invalid
                }
            }
        }
        if (reader->canRead()) {
            // reader says we can read. Attempt to actually read image
            QImage anImage = reader->read();
            if (anImage.isNull()) {
                // Reading image failed.
                return QFrameInfo(); // Invalid
            }
            if (frameNumber > greatestFrameNumber)
                greatestFrameNumber = frameNumber;
            QPixmap aPixmap = QPixmap::fromImage(anImage);
            int aDelay = reader->nextImageDelay();
            return QFrameInfo(aPixmap, aDelay);
        } else {
            // We've read all frames now. Return an end marker
            haveReadAll = true;
            return QFrameInfo::endMarker();
        }
    }

    // CacheMode == CacheAll
    if (frameNumber > greatestFrameNumber) {
        // Frame hasn't been read from file yet. Try to do it
        for (int i = greatestFrameNumber + 1; i <= frameNumber; ++i) {
            if (reader->canRead()) {
                // reader says we can read. Attempt to actually read image
                QImage anImage = reader->read();
                if (anImage.isNull()) {
                    // Reading image failed.
                    return QFrameInfo(); // Invalid
                }
                greatestFrameNumber = i;
                QPixmap aPixmap = QPixmap::fromImage(anImage);
                int aDelay = reader->nextImageDelay();
                QFrameInfo info(aPixmap, aDelay);
                // Cache it!
                frameMap.insert(i, info);
                if (i == frameNumber) {
                    return info;
                }
            } else {
                // We've read all frames now. Return an end marker
                haveReadAll = true;
                return QFrameInfo::endMarker();
            }
        }
    }
    // Return info for requested (cached) frame
    return frameMap.value(frameNumber);
}

/*!
    \internal

    Attempts to advance the animation to the next frame.
    If successful, currentFrameNumber, currentPixmap and
    nextDelay are updated accordingly, and true is returned.
    Otherwise, false is returned.
    When false is returned, isDone() can be called to
    determine whether the animation ended gracefully or
    an error occurred when reading the frame.
*/
bool QMoviePrivate::next()
{
    QTime time;
    time.start();
    QFrameInfo info = infoForFrame(nextFrameNumber);
    if (!info.isValid())
        return false;
    if (info.isEndMarker()) {
        // We reached the end of the animation.
        if (isFirstIteration) {
            if (nextFrameNumber == 0) {
                // No frames could be read at all (error).
                return false;
            }
            // End of first iteration. Initialize play counter
            playCounter = reader->loopCount();
            isFirstIteration = false;
        }
        // Loop as appropriate
        if (playCounter != 0) {
            if (playCounter != -1) // Infinite?
                playCounter--;     // Nope
            nextFrameNumber = 0;
            return next();
        }
        // Loop no more. Done
        return false;
    }
    // Image and delay OK, update internal state
    currentFrameNumber = nextFrameNumber++;
    QSize scaledSize = reader->scaledSize();
    if (scaledSize.isValid() && (scaledSize != info.pixmap.size()))
        currentPixmap = QPixmap::fromImage( info.pixmap.toImage().scaled(scaledSize) );
    else
        currentPixmap = info.pixmap;
    nextDelay = speedAdjustedDelay(info.delay);
    // Adjust delay according to the time it took to read the frame
    int processingTime = time.elapsed();
    if (processingTime > nextDelay)
        nextDelay = 0;
    else
        nextDelay = nextDelay - processingTime;
    return true;
}

/*! \internal
 */
void QMoviePrivate::_q_loadNextFrame()
{
    _q_loadNextFrame(false);
}

void QMoviePrivate::_q_loadNextFrame(bool starting)
{
    Q_Q(QMovie);
    if (next()) {
        if (starting && movieState == QMovie::NotRunning) {
            enterState(QMovie::Running);
            emit q->started();
        }

        if (frameRect.size() != currentPixmap.rect().size()) {
            frameRect = currentPixmap.rect();
            emit q->resized(frameRect.size());
        }

        emit q->updated(frameRect);
        emit q->frameChanged(currentFrameNumber);

        if (movieState == QMovie::Running)
            nextImageTimer.start(nextDelay);
    } else {
        // Could not read another frame
        if (!isDone()) {
            emit q->error(reader->error());
        }

        // Graceful finish
        if (movieState != QMovie::Paused) {
            nextFrameNumber = 0;
            isFirstIteration = true;
            playCounter = -1;
            enterState(QMovie::NotRunning);
            emit q->finished();
        }
    }
}

/*!
    \internal
*/
bool QMoviePrivate::isValid() const
{
    return (greatestFrameNumber >= 0) // have we seen valid data
        || reader->canRead(); // or does the reader see valid data
}

/*!
    \internal
*/
bool QMoviePrivate::jumpToFrame(int frameNumber)
{
    if (frameNumber < 0)
        return false;
    if (currentFrameNumber == frameNumber)
        return true;
    nextFrameNumber = frameNumber;
    if (movieState == QMovie::Running)
        nextImageTimer.stop();
    _q_loadNextFrame();
    return (nextFrameNumber == currentFrameNumber+1);
}