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mapToScene equivalent for a scaled QImage?
I have a QImage that has a rectangle inside. After scaling it, I would like to know the coordinates of the scaled rectangle in the new, scaled QImage. Is there an easy way to achieve this?
Thanks a lot.
well, how do you
know the coordinates of the original rectangle ?
Im not sure i 100% understand. you have an image, where inside
a rect is DRAWN ?
then you scale the whole image
and this drawn rect is also scaled with whole image?
and then you want to find the corrdinates?
inside the image?
@mrjj exactly. There's a rectangle at position (x, y), whose size is (w, h) and I would like to know the new position (x', y') as well as its new size (w', h')
But do u even have the original coordinates of the rect?
@mrjj Yes. I think I'm going to go with
x' = scale_x*x,
y' = scale_y*y,
w' = scale_x*wand
h' = scale_y*hbut I'd rather Qt did it for me. This way I'd be sure there's no mistake.
Well since its drawn inside othe image, not sure about any good Qt way :)
QTransform matrix = QTransform().scale(0.5, 0.5); QImage scaledImg = img.transformed( matrix, Qt::SmoothTransformation ); QRect scaledRect = matrix.mapRect( originRect );
oh, i read the question as having a smaller drawn rect inside image. :)
Thanks to both of you :-)