Drawing a line on a QImage

[Pritcher]

I am trying to draw a line with penSize>=2 on a QImage . That is what I got:
1bFS9uGL-e0.jpg

Here is how I do it

QPainter painter( getImage() );
QPen pen( getLeftColor(),
	getPenSize(),
	Qt::SolidLine,
	Qt::SquareCap,
	Qt::MiterJoin );
painter.setPen( pen );
if ( _startPoint == _endPoint )
	painter.drawPoint( _endPoint );
else
	painter.drawLine( _startPoint, _endPoint );
painter.end();

QPainter painter( getImage() );
QPen pen( getLeftColor(),
	getPenSize(),
	Qt::SolidLine,
	Qt::SquareCap,
	Qt::MiterJoin );
painter.setPen( pen );
if ( _startPoint == _endPoint )
	painter.drawPoint( _endPoint );
else
	painter.drawLine( _startPoint, _endPoint );
painter.end();

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How can I fix this graphical artifact?

[d_stranz]

Here is how I do it

Oh really? There is nothing I can see in the fragment of code you have posted that will produce the effect shown in your screenshot. Your code draws either a line or a single point, not a series of jagged points.