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#include <QtGui>
#include <QtDebug>

#include <private/qpaintengineex_p.h>
#include <private/qpaintbuffer_p.h>

class ReplayWidget : public QWidget
{
    Q_OBJECT
public:
    ReplayWidget(const QString &filename);

    void paintEvent(QPaintEvent *event);
    void resizeEvent(QResizeEvent *event);

public slots:
    void updateRect();

public:
    QList<QRegion> updates;
    QPaintBuffer buffer;

    int currentFrame;
    int currentIteration;
    QTime timer;

    QList<uint> visibleUpdates;
    QList<uint> iterationTimes;
    QString filename;
};

void ReplayWidget::updateRect()
{
    if (!visibleUpdates.isEmpty())
        update(updates.at(visibleUpdates.at(currentFrame)));
}

void ReplayWidget::paintEvent(QPaintEvent *)
{
    QPainter p(this);

//    p.setClipRegion(frames.at(currentFrame).updateRegion);

    buffer.draw(&p, visibleUpdates.at(currentFrame));

    ++currentFrame;
    if (currentFrame >= visibleUpdates.size()) {
        currentFrame = 0;
        ++currentIteration;

        if (currentIteration == 3)
            timer.start();
        else if (currentIteration > 3) {
            iterationTimes << timer.elapsed();
            timer.restart();

            if (iterationTimes.size() >= 3) {
                qreal mean = 0;
                qreal stddev = 0;
                uint min = INT_MAX;

                for (int i = 0; i < iterationTimes.size(); ++i) {
                    mean += iterationTimes.at(i);
                    min = qMin(min, iterationTimes.at(i));
                }

                mean /= qreal(iterationTimes.size());

                for (int i = 0; i < iterationTimes.size(); ++i) {
                    qreal delta = iterationTimes.at(i) - mean;
                    stddev += delta * delta;
                }

                stddev = qSqrt(stddev / iterationTimes.size());

                qSort(iterationTimes.begin(), iterationTimes.end());
                uint median = iterationTimes.at(iterationTimes.size() / 2);

                stddev = 100 * stddev / mean;

                if (iterationTimes.size() >= 10 || stddev < 4) {
                    printf("%s, iterations: %d, frames: %d, min(ms): %d, median(ms): %d, stddev: %f %%, max(fps): %f\n", qPrintable(filename),
                            iterationTimes.size(), visibleUpdates.size(), min, median, stddev, 1000. * visibleUpdates.size() / min);
                    deleteLater();
                    return;
                }
            }
        }
    }

    QTimer::singleShot(0, this, SLOT(updateRect()));
}

void ReplayWidget::resizeEvent(QResizeEvent *event)
{
    visibleUpdates.clear();

    QRect bounds = rect();
    for (int i = 0; i < updates.size(); ++i) {
        if (updates.at(i).intersects(bounds))
            visibleUpdates << i;
    }

    if (visibleUpdates.size() != updates.size())
        printf("Warning: skipped %d frames due to limited resolution\n", updates.size() - visibleUpdates.size());

}

ReplayWidget::ReplayWidget(const QString &filename_)
    : currentFrame(0)
    , currentIteration(0)
    , filename(filename_)
{
    setWindowTitle(filename);
    QFile file(filename);

    if (!file.open(QIODevice::ReadOnly)) {
        printf("Failed to load input file '%s'\n", qPrintable(filename_));
        return;
    }

    QDataStream in(&file);

    char *data;
    uint size;
    in.readBytes(data, size);
    bool isTraceFile = size == 7 && qstrncmp(data, "qttrace", 7) == 0;
    delete [] data;
    if (!isTraceFile) {
        printf("File '%s' is not a trace file\n", qPrintable(filename_));
        return;
    }

    in >> buffer >> updates;
    printf("Read paint buffer with %d frames\n", buffer.numFrames());

    resize(buffer.boundingRect().size().toSize());

    setAutoFillBackground(false);
    setAttribute(Qt::WA_NoSystemBackground);

    QTimer::singleShot(10, this, SLOT(updateRect()));
}

int main(int argc, char **argv)
{
    QApplication app(argc, argv);

    if (argc <= 1 || qstrcmp(argv[1], "-h") == 0 || qstrcmp(argv[1], "--help") == 0) {
        printf("Replays a tracefile generated with '-graphicssystem trace'\n");
        printf("Usage:\n  > %s [traceFile]\n", argv[0]);
        return 1;
    }

    QFile file(argv[1]);
    if (!file.exists()) {
        printf("%s does not exist\n", argv[1]);
        return 1;
    }

    ReplayWidget *widget = new ReplayWidget(argv[1]);

    if (!widget->updates.isEmpty()) {
        widget->show();
        return app.exec();
    }

}
#include "main.moc"