QPainter fill artefact

[koan]

I want to draw some triangles in my widget pointing up: ie. two vertices are on the same horizontal line and a third vertex halfway between these two points and above.

When the triangle is not filled the top vertex is "sharp" but when I draw the triangle filled, it does not have a "sharp" point: an extra diagonal line of pixels is added on the left side, outside of the triangle.


void widget::paintEvent(QPaintEvent *)
{
QPainter p(this);

p.setPen(Qt::black);
p.setBrush(Qt::black);

int halfwidth = 7;
int height = 7;

QPolygon triangle;

triangle.clear();
triangle << QPoint(10+halfwidth, 10-height);
triangle << QPoint(10, 10);
triangle << QPoint(10+2*halfwidth, 10);
p.drawPolygon(triangle);
}

5299

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