c++ - Rendering a QGraphicsScene to QImage results in objects being placed on a side of QImage -

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my qgraphicsscene quite large, , qgraphicsview fit small portion of it.

i print/save qgraphicsscene 

outputview::outputview(qwidget *parent)     : qgraphicsview(parent) {...}  void outputview::savetoimage()  {     qimage image(scene()->scenerect().size().tosize(), qimage::format_mono);     image.fill(qt::transparent);     qpainter painter(&image);     render(&painter);     image.save("output.png"); }

of course experimenting, placing objects in center of viewport...

the saved image contains objects, location of objects on left side of image

input: enter image description here

output: enter image description here (screenshot windows photo viewer)

it seems image created correct size, viewport contents rendered - top left corner of viewport on top left corner of image, leaving rest of image empty.

why happening ? doing wrong ?

update:

trying 

fitinview(scene()->scenerect());

results in viewport showing entire image, zoomed ... saved image still contains viewport (only tiny)

enter image description here

and answer in additional explanation.

i should have done

scene()->render(&painter);

i rendering viewport.... not scene


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