Sorry lkzhao that I don't really have time to debug and make a pull request to help you but I hope I could at least report what I found while using your control.
Currently dismiss a ViewController which was presented modally with custom transition as ElasticTransition only work with animated = true. If animated is false, it will result in black / empty screen.
I guess this has something with rendering the underneath view controller while performing the custom transition.
Sorry lkzhao that I don't really have time to debug and make a pull request to help you but I hope I could at least report what I found while using your control.
Currently dismiss a ViewController which was presented modally with custom transition as ElasticTransition only work with animated = true. If animated is false, it will result in black / empty screen.
I guess this has something with rendering the underneath view controller while performing the custom transition.