Home/ Questions/Q 8647415
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-12T13:03:56+00:00

I have an image. I want to drag that image along a path. Path

  • 0

I have an image. I want to drag that image along a path. Path can be of circular or rectangular shape. If the image is being touched and dragged, it should only travel along the path and should not leave the path. I have tried using Core Graphics and Core animations but can’t find the right way of doing it. I have searched on the net but it always shows how to move an object along a path. Can’t find anything about dragging an object along a path. Also I have found that their is NO method, provided by Apple, to extract points from a UIBezierPath.

Is their anyway of doing this?

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    The UIBezierPath class has an instance method called - (BOOL)containsPoint:. With this method and 2 UIBezierPaths, you can check if your object is moving along the path.

    +---------+
|xxxxxxxxx|
|x+-----+x|
|x|     |x|
|x|     |x|
|x|     |x|
|x+-----+x|
|xxxxxxxxx|
+---------+

    The trick here is to make 1 path slightly smaller than the first (maybe 2 pixels), while ensuring that both paths have a common center. The path/route that your object must now travel will be the difference of the areas of the bezier paths, which you get from calling - (BOOL)containsPoint:.

    If your object is contained within the big UIBezierPath, but not in the small one, then you know that you are on the correct path.

    • 0