How To Support Multi touch Simultaneously for Several Users

[masoudmm]

Hi there, first of all sorry for double post..., second, thank you for the app :) I wonder how can I change your code to support multi touch simultaneously for several users, in other words users can zoom, rotate and drag several image simultaneously. you are using the history of every touch event in your app, how can we use the specific history for every image object in multi touch canvas? is this a good idea??

[sadi-asif]

@masoudmm Have you found the solution of your query?

[lukehutch]

Hi @masoudmm and @sadi-asif , sorry, I didn't see this before now.

This is exceptionally hard to do in a reliable way, because there is no way to tell which touchpoint was triggered by the finger of which user.

The best you could probably do is to find all pairings of closest points, assuming that all users always have two fingers on the screen. However, I don't know how you would then handle single-point interactions from multiple users, as opposed to one large pinch-zoom gesture from one user.

If you need only single-point interactions from multiple users, the code is easy, you just assume each touch-point comes from a separate user.

If you have different regions of the screen for each user, then the problem is easier, because all touchpoints in one region could be assigned to one user.

I guess the problem itself is not well-defined, since the interpretation of different clusters of touch points would be highly application-specific.