source: tests/blit/blit.cpp

#include <QDebug>

#include <QtGui>

/*
 * This test calculates the roundtrip speed of copy offscreen buffer to window
 * operations. Besides the time necessary for copying pixels, this also includes
 * the time necessary to fill 2D rectangles in the offscreen buffer, deliver
 * paint and timer messages and so on.
 *
 * To also get the speed of only the copy operatoins themselves, add
 *
 *      #define QT_LOG_BLITSPEED
 *
 * to the beginning of qapplication_pm.cpp and qwindowsurface_raster.cpp.
 *
 * Hint: in order to get the most realistic numbers, let the test run until the
 * average speed printed in the window title stabilizes (i.e. stops to grow).
 **/

////////////////////////////////////////////////////////////////////////////////

class MyWidget : public QWidget
{
public:

    MyWidget() : mUpdateTID(0), mStatTID(0), mNumPixels(0)
    {
    };

    ~MyWidget()
    {
        unsigned long long elapsed = mElapsedTimer.elapsed();
        qWarning() << "Stats:";
        qWarning() << "  total pixels blitted           :" << mNumPixels;
        qWarning() << "  total time, ms                 :" << elapsed;
        qWarning() << "  average roundtrip speed, px/ms :" << mNumPixels / elapsed;
    }

    void startWork()
    {
        mElapsedTimer.start();
        mUpdateTID = startTimer(0);
        mStatTID = startTimer(500);
    }

    void paintEvent(QPaintEvent *aE)
    {
        QPainter p(this);

        QRect r = aE->rect();

#if 0
        QColor c = QColor(rand() / (RAND_MAX / 255),
                          rand() / (RAND_MAX / 255),
                          rand() / (RAND_MAX / 255));