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QGraphicsView - move item by non linear value...



  • 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?


  • Lifetime Qt Champion

    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.



  • @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)
    

    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


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