Running my application under OSX Leopard and Windows XP, using bootcamp,
hence with the same hardware, I have always noticed that running under
Windows seems much faster. For instance run Assistant and scroll and
resize the window, it's quite a different feeling.
I have therefore run a very simplistic benchmark, see further.
Using the 4.5 rc1 32 bit supplied binaries, the results are (Mac Pro 2.8
GHz), in RELEASE mode:
Under Windows:
With QImage as paint device: 78 ms
With direct QPainter device: 78 ms
Under OSX:
With QImage as paint device: 98 ms
With direct QPainter device: 562 ms
Hence:
1) Drawing to a QImage is meant to be platform independant,
this means here that the VC++ 2008 compiler seems about 20% faster that
GCC.
I am wondering if using an alternate GCC version could help (LLVM-GCC 4.2
?)
2) Using QPainter directly (OSX api) to draw is dead slow, 550% slower
that drawing to QImage.
I am wondering if there is any interest to this? Is it even normal?
Philippe
//
-----------------------------------------------------------------------------
#include <QtGui>
//#define USE_IMAGE 1
class TMainWindow : public QMainWindow
{
public:
TMainWindow();
void paintEvent(QPaintEvent* ev);
};
//
-----------------------------------------------------------------------------
TMainWindow::TMainWindow()
:
QMainWindow(0)
{
resize(800,400);
}
//
-----------------------------------------------------------------------------
void TMainWindow::paintEvent(QPaintEvent*)
{
QTime time;
time.start();
QRect r = rect();
#if USE_IMAGE
QImage image(r.size(), QImage::Format_RGB32);
QPainter painter(&image);
painter.initFrom(this);
#else
QPainter painter(this);
#endif
for (int i = 0; i < 100; i++)
{
painter.fillRect(r, QBrush(Qt::white));
painter.setPen(Qt::blue);
for (int j = 0; j < 100; j++)
{
painter.drawLine(0, 0, qrand() % 1000, qrand() % 1000);
}
}
QString s = QString::number(time.elapsed());
s += " ms";
painter.setBackgroundMode(Qt::OpaqueMode);
painter.drawText(20, 60, s);
#if USE_IMAGE
QPainter painter0(this);
painter0.drawImage(0, 0, image);
#endif
}
//
-----------------------------------------------------------------------------
int main(int argc, char** argv)
{
QApplication app(argc, argv);
TMainWindow w;
w.show();
return app.exec();
}
//
-----------------------------------------------------------------------------
_______________________________________________
Qt4-preview-feedback mailing list
[email protected]
http://lists.trolltech.com/mailman/listinfo/qt4-preview-feedback
