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#include "qvideosink.h"

#include "qvideoframeformat.h"
#include "qvideoframe.h"
#include "qmediaplayer.h"
#include "qmediacapturesession.h"

#include <qvariant.h>
#include <qpainter.h>
#include <qmatrix4x4.h>
#include <QDebug>
#include <private/qplatformmediaintegration_p.h>
#include <private/qplatformvideosink_p.h>

QT_BEGIN_NAMESPACE

class QVideoSinkPrivate {
public:
    QVideoSinkPrivate(QVideoSink *q)
        : q_ptr(q)
    {
        videoSink = QPlatformMediaIntegration::instance()->createVideoSink(q);
    }
    ~QVideoSinkPrivate()
    {
        delete videoSink;
    }
    void unregisterSource()
    {
        if (!source)
            return;
        auto *old = source;
        source = nullptr;
        if (auto *player = qobject_cast<QMediaPlayer *>(old))
            player->setVideoSink(nullptr);
        else if (auto *capture = qobject_cast<QMediaCaptureSession *>(old))
            capture->setVideoSink(nullptr);
    }

    QVideoSink *q_ptr = nullptr;
    QPlatformVideoSink *videoSink = nullptr;
    QObject *source = nullptr;
    bool fullScreen = false;
    WId window = 0;
    QRhi *rhi = nullptr;
    Qt::AspectRatioMode aspectRatioMode = Qt::KeepAspectRatio;
    QRectF targetRect;
    float brightness = 0;
    float contrast = 0;
    float saturation = 0;
    float hue = 0;
    Qt::BGMode backgroundMode = Qt::OpaqueMode;
};

/*!
    \class QVideoSink

    \brief The QVideoSink class represents a generic sink for video data.
    \inmodule QtMultimedia
    \ingroup multimedia

    The QVideoSink class can be used to retrieve video data on a frame by frame
    basis from Qt Multimedia.

    QVideoSink can operate in two modes. In the first mode, it can render the video
    stream to a native window of the underlying windowing system. In the other mode,
    it will provide individual video frames to the application developer through the
    newVideoFrame() signal.

    The video frame can then be used to read out the data of those frames and handle them
    further. When using QPainter, the QVideoFrame can be drawing using the paint() method
    in QVideoSink.

    QVideoFrame objects can consume a significant amount of memory or system resources and
    should thus not be held for longer than required by the application.

    \sa QMediaPlayer, QMediaCaptureSession

*/

/*!
    Constructs a new QVideoSink object with \a parent.
 */
QVideoSink::QVideoSink(QObject *parent)
    : QObject(parent),
    d(new QVideoSinkPrivate(this))
{
    qRegisterMetaType<QVideoFrame>();
}

/*!
    Destroys the object.
 */
QVideoSink::~QVideoSink()
{
    d->unregisterSource();
    delete d;
}

/*!
    Returns the native window id that the sink is currently rendering to.
 */
WId QVideoSink::nativeWindowId() const
{
    return d->window;
}

/*!
    Tells QVideoSink to render directly to the native window \a id. This is usually more
    resource efficient than rendering individual video frames.

    The newVideoFrame() signal will never get emitted in this mode.

    Setting \a id to 0 will stop rendering to a native window.
 */
void QVideoSink::setNativeWindowId(WId id)
{
    if (d->window == id)
        return;
    d->window = id;
    if (d->videoSink != nullptr)
        d->videoSink->setWinId(id);
}

/*!
    \internal
    The QRhi instance being used to create texture data in the video frames.
 */
QRhi *QVideoSink::rhi() const
{
    return d->rhi;
}

/*!
    \internal
    Sets the QRhi instance being used to create texture data in the video frames to \a rhi.
 */
void QVideoSink::setRhi(QRhi *rhi)
{
    if (d->rhi == rhi)
        return;
    d->rhi = rhi;
    d->videoSink->setRhi(rhi);
}

/*!
    Render the video full screen. This is often more resource efficient than rendering to
    only parts of the screen.

    The newVideoFrame() signal will never get emitted when rendering full screen.
 */
void QVideoSink::setFullScreen(bool fullscreen)
{
    if (d->fullScreen == fullscreen)
        return;
    d->fullScreen = fullscreen;
    d->videoSink->setFullScreen(fullscreen);
    emit fullScreenChanged(d->fullScreen);
}

/*!
    Returns true when rendering full screen.
 */
bool QVideoSink::isFullScreen() const
{
    return d->fullScreen;
}

Qt::AspectRatioMode QVideoSink::aspectRatioMode() const
{
    return d->aspectRatioMode;
}

void QVideoSink::setAspectRatioMode(Qt::AspectRatioMode mode)
{
    if (d->aspectRatioMode == mode)
        return;
    d->aspectRatioMode = mode;
    d->videoSink->setAspectRatioMode(mode);
    emit aspectRatioModeChanged(mode);
}

QRectF QVideoSink::targetRect() const
{
    return d->targetRect;
}

void QVideoSink::setTargetRect(const QRectF &rect)
{
    if (d->targetRect == rect)
        return;
    d->targetRect = rect;
    if (d->videoSink != nullptr)
        d->videoSink->setDisplayRect(rect.toRect());
}

float QVideoSink::brightness() const
{
    return d->brightness;
}

void QVideoSink::setBrightness(float brightness)
{
    brightness = qBound(-1., brightness, 1.);
    if (d->brightness == brightness)
        return;
    d->brightness = brightness;
    d->videoSink->setBrightness(brightness);
    emit brightnessChanged(brightness);
}

float QVideoSink::contrast() const
{
    return d->contrast;
}

void QVideoSink::setContrast(float contrast)
{
    contrast = qBound(-1., contrast, 1.);
    if (d->contrast == contrast)
        return;
    d->contrast = contrast;
    d->videoSink->setContrast(contrast);
    emit contrastChanged(contrast);
}

float QVideoSink::hue() const
{
    return d->hue;
}

void QVideoSink::setHue(float hue)
{
    hue = qBound(-1., hue, 1.);
    if (d->hue == hue)
        return;
    d->hue = hue;
    d->videoSink->setHue(hue);
    emit hueChanged(hue);
}

float QVideoSink::saturation() const
{
    return d->saturation;
}

void QVideoSink::setSaturation(float saturation)
{
    saturation = qBound(-1., saturation, 1.);
    if (d->saturation == saturation)
        return;
    d->saturation = saturation;
    d->videoSink->setSaturation(saturation);
    emit saturationChanged(saturation);
}

Qt::BGMode QVideoSink::backgroundMode() const
{
    return d->backgroundMode;
}

void QVideoSink::setBackgroundMode(Qt::BGMode mode)
{
    d->backgroundMode = mode;
}

/*!
    Use a QPainter to render the QVideoFrame \a f. Rendering will usually happen in without hardware
    acceleration when using this method.
*/
void QVideoSink::paint(QPainter *painter, const QVideoFrame &f)
{
    QVideoFrame frame(f);
    if (!frame.isValid()) {
        painter->fillRect(d->targetRect, painter->background());
        return;
    }

    auto imageFormat = QVideoFrameFormat::imageFormatFromPixelFormat(frame.pixelFormat());
    // Do not render into ARGB32 images using QPainter.
    // Using QImage::Format_ARGB32_Premultiplied is significantly faster.
    if (imageFormat == QImage::Format_ARGB32)
        imageFormat = QImage::Format_ARGB32_Premultiplied;

    QVideoFrameFormat::Direction scanLineDirection = QVideoFrameFormat::TopToBottom;//format.scanLineDirection();
    bool mirrored = false;//format.isMirrored();

    QSizeF size = frame.size();
    QRectF source = QRectF(0, 0, size.width(), size.height());
    QRectF targetRect = d->targetRect;
    if (d->aspectRatioMode == Qt::KeepAspectRatio) {
        size.scale(targetRect.size(), Qt::KeepAspectRatio);
        targetRect = QRect(0, 0, size.width(), size.height());
        targetRect.moveCenter(d->targetRect.center());
        // we might not be drawing every pixel, fill the leftover black
        if (d->backgroundMode == Qt::OpaqueMode && d->targetRect != targetRect) {
            if (targetRect.top() > d->targetRect.top()) {
                QRectF top(d->targetRect.left(), d->targetRect.top(), d->targetRect.width(), targetRect.top() - d->targetRect.top());
                painter->fillRect(top, Qt::black);
            }
            if (targetRect.left() > d->targetRect.left()) {
                QRectF top(d->targetRect.left(), targetRect.top(), targetRect.left() - d->targetRect.left(), targetRect.height());
                painter->fillRect(top, Qt::black);
            }
            if (targetRect.right() < d->targetRect.right()) {
                QRectF top(targetRect.right(), targetRect.top(), d->targetRect.right() - targetRect.right(), targetRect.height());
                painter->fillRect(top, Qt::black);
            }
            if (targetRect.bottom() < d->targetRect.bottom()) {
                QRectF top(d->targetRect.left(), targetRect.bottom(), d->targetRect.width(), d->targetRect.bottom() - targetRect.bottom());
                painter->fillRect(top, Qt::black);
            }
        }
    } else if (d->aspectRatioMode == Qt::KeepAspectRatioByExpanding) {
        QSizeF targetSize = targetRect.size();
        targetSize.scale(size, Qt::KeepAspectRatio);

        QRectF s(0, 0, targetSize.width(), targetSize.height());
        s.moveCenter(source.center());
        source = s;
    }

    if (frame.map(QVideoFrame::ReadOnly)) {
        QImage image = frame.toImage();

        const QTransform oldTransform = painter->transform();
        QTransform transform = oldTransform;
        if (scanLineDirection == QVideoFrameFormat::BottomToTop) {
            transform.scale(1, -1);
            transform.translate(0, -targetRect.bottom());
            targetRect = QRectF(targetRect.x(), 0, targetRect.width(), targetRect.height());
        }

        if (mirrored) {
            transform.scale(-1, 1);
            transform.translate(-targetRect.right(), 0);
            targetRect = QRectF(0, targetRect.y(), targetRect.width(), targetRect.height());
        }
        painter->setTransform(transform);
        painter->drawImage(targetRect, image, source);
        painter->setTransform(oldTransform);

        frame.unmap();
    } else if (frame.isValid()) {
        // #### error handling
    } else {
        painter->fillRect(d->targetRect, Qt::black);
    }
}

/*!
    \internal
*/
QPlatformVideoSink *QVideoSink::platformVideoSink() const
{
    return d->videoSink;
}

/*!
    Returns the size of the video currently being played back. If no video is being played,
    this method returns an invalid size.
 */
QSize QVideoSink::videoSize() const
{
    return d->videoSink ? d->videoSink->nativeSize() : QSize{};
}

void QVideoSink::setSource(QObject *source)
{
    if (d->source == source)
        return;
    if (source)
        d->unregisterSource();
    d->source = source;
}

QT_END_NAMESPACE

#include "moc_qvideosink.cpp"