Envelope of two dataset

[giusepped]

I have a math question.
I have two QPolygonF, wiht different size.
I would build a new QPolygonF composed of the envolope of the two polygons.
For example:

QPOlygonF p1 << QPointF(1,1)<<QPointF(10,20)<<QPointF(20,5);
QPolygon p2 <<   QPointF(5,10)<<QPointF(11,0);

QPOlygonF p1 << QPointF(1,1)<<QPointF(10,20)<<QPointF(20,5);
QPolygon p2 <<   QPointF(5,10)<<QPointF(11,0);

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The resutl should be the polygon

QPoinF(1,1),QPointF(5,10),QPointF(10,20)<<QPointF( 20,5)