QT App performance is too slow on OSX

**stampede** · 28th May 2011, 08:30

I'm not a OSX user, so I don't know the answer, but what I know is that the getColor method could be done better.
I understand that it's purpose is to grab the (0,0) pixel color from widget, so I don't see why you need to grab the whole desktop ? Can't you use the QWidget::winId()? And if all you need is this one pixel, pass a QRectF(0,0,1,1) to QPixmap::grabWindow, no need to scale anything, so your method will look like:

Qt Code:

Switch view

QRgb getColor(const QWidget * grabme)
{
    DEBUG_HIGH_LEVEL << Q_FUNC_INFO;
 
    QPixmap pix = QPixmap::grabWindow(grabme->winId(),0,0,1,1);
    QImage im = pix.toImage();
    QRgb result = im.pixel(0,0);
 
    DEBUG_HIGH_LEVEL << "QRgb result =" << hex << result;
 
    return result;
}

QRgb getColor(const QWidget * grabme)
{
    DEBUG_HIGH_LEVEL << Q_FUNC_INFO;
 
    QPixmap pix = QPixmap::grabWindow(grabme->winId(),0,0,1,1);
    QImage im = pix.toImage();
    QRgb result = im.pixel(0,0);
 
    DEBUG_HIGH_LEVEL << "QRgb result =" << hex << result;
 
    return result;
}

To copy to clipboard, switch view to plain text mode

I think it could be faster.