QGraphicsView - move item by non linear value...

[Dariusz]

Hey

Right now the item is being moved to the mouse position.

I would like a way to multiply the amount of mouse movement... say if I have a multiplier of 0.5, then move of 100 pixels in mouse distance would result in item moving by 50 pixels...

Does qt offer any way of doing this?

[SGaist]

Hi,

AFAIK, not directly (but I may be wrong though)

Can you explain your use case ? It sounds strange to me that if I move an object with my mouse that it only moves half-way.

[Dariusz]

@SGaist Its about precision moves, if user wants to move by tiny bit, scaling mouse movement by x value would allow that to happen. Else he would have to type 0.0001 0.0002 0.0003 etc etc.

I think I could handle it using itemChange() and record initial mouse click press/release and calculate delta using that..

Yep that seem to do the trick... I can now move my items by tiny amount and doing "Long precise drags"

            deltaX = (newPos.x() - self.mMousePressPosition.x()) / 2
            newPos.setX(newPos.x() - deltaX)
            deltaY = (newPos.y() - self.mMousePressPosition.y()) / 2
            newPos.setY(newPos.y() - deltaY)

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Small edit, function above works for "simple" items, but as soon as I get to child items with parent it appear to break... sigh. Needs some more math there