Rotate items in qwt

[Uwe]

but how can i display the QPolygon on qwtpolt after that ??

The same way like in your code above - or even easier this way:

curve1->setSamples( polygon );

curve1->setSamples( polygon );

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Uwe

[jesse_mark]

[QUOTE=Uwe;224305]

QPolygonF points = transform.mapToPolygon( QRectF( 0, 0, rect.width(), rect.height() );

QPolygonF points = transform.mapToPolygon( QRectF( 0, 0, rect.width(), rect.height() );

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i used QRect as there is no transform.mapToPolygon takes QRectF

this is what i wrote :

QRect grid;
           grid.setTop(Ox);
           grid.setLeft(Oy);
           grid.setHeight(Hight);
           grid.setWidth(Width);
 
 
           QTransform Tr;
           Tr.translate(grid.top(),grid.left()); 
           Tr.rotate(30);
 
          QPolygonF points = Tr.mapToPolygon(QRect(0, 0, grid.width(), grid.height()));
 
curve1->setSamples( points );

QRect grid;
           grid.setTop(Ox);
           grid.setLeft(Oy);
           grid.setHeight(Hight);
           grid.setWidth(Width);


           QTransform Tr;
           Tr.translate(grid.top(),grid.left()); 
           Tr.rotate(30);

          QPolygonF points = Tr.mapToPolygon(QRect(0, 0, grid.width(), grid.height()));

curve1->setSamples( points );

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but the resulted graph was not rectangle it was

qwt.jpeg

[Uwe]

It is a rectangle, but setting a curve brush means that the area below the points ( to the baseline ) is filled - not the area inside the polygon.

But I already told you in my first answer what type of plot item you need. I recommend to copy the RectItem of the navigation example and modify it so that it works with polygons. In the draw method you have to transform the points of the polygon one by one ( instead of a rectangle once ).

Another option is to keep the RectItem as it is, beside rotating the translated rectangle inside of the draw method - but I don't know your use case.

Uwe