How to put a pixel on window?

hjpark

Hi Guys..

I want to draw a RGB pixel on a window.
but.. I dont find an API like a putPixel on C lib.

Could you let me know how to put a RGB pixel on a window?
thanks a lot
HJ

Wieland

@hjpark Hi, and welcome to the Qt forum! Simply derive from QWidget and override its paintEvent method. You can then draw whatever you want inside there.

hjpark

@Wieland Thanks a lot for your help.. I succeeded to draw a point with this code but I have to draw a point whenever getting some datas from a USB device. but, I don't know how to raise paintEvent manually when I want.
It seems to be called when the widget showed but I don't know how to call paintEvent when I get a data from USB devie. pls help me again . thanks a lot.

void Widget::paintEvent(QPaintEvent *event)
{
Q_UNUSED(event);

QPainter painter;
painter.begin(this);

painter.setPen(Qcloor(10,10,10);
painter.drawPoint(10,10);
painter.end();

}

Wieland

Once you received new data and want the widget to be painted again just call this function on it: [slot] void QWidget::update(), see also: QWidget Class.