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iosipadtouchmove

How to smoothly move a UIView with the users finger on iOS

in my app I have a UIImageView representing a chalk. The user can pick that up and drag it over the screen to draw with it.

I implemented that using touchesBegan, touchesMoved and touchesEnded. In touchesMoved I move the center of my UIImageView to the current touch location and draw a line with core graphics from the last to the current location.

This works well but the image view movement isn't very smooth and it also lags behind the touch. I already tried to use a UIPanGestureRecognizer (didn't recognize the gesture) and a UIScrollView in which I placed the chalk (didn't really figure out how to configure it so that it could be moved far enough in all directions).

Can you give me some hints how to improve the quality of my chalk movement?

Thanks!

Solution

  • I rewrote how the movement is calculated and it is a little smoother now. Not perfect, but it's enough.