By looking at Instagram's pinch to zoom feature, we can notice the following things:

1. The image view becomes a full-screen view and overlays other views.
2. By releasing the image view, it will have a transition animation back to its original position.

I've created a simple project (pretty rough) to try to implement it and looks like we will need to rewrite the ZoomableController.Listener events.

The DefaultZoomableController has complete code of detecting onTransformBegin and onTransformEnd.

If we are going to set the custom ZoomableController.Listener, we will need to copy the most part of the sample code and add a few codes to make the image view becomes full screen (or overlay) when onTransformBegin and transit to its original place when onTransformEnd

Note:

• Create a full-screen dialog with transparent background might work but will need to think about an issue when losing focus on the image
• setTapListener does not work on multiple touch event, so it could be ignored.

Also found this repository that implement exactly the same feature, but unfortunately it is using Glide

https://github.com/okaybroda/ImageZoom

Found an ImageZoomHelper class inside the repo above, and it nicely makes the instagram-style pinch-zoom work!

Demo video: https://www.youtube.com/watch?v=sw-7MrK5nTw
Demo repo: https://github.com/cooltey/InstagramLikePinchZoom