question: private void saveTouchStart ( MotionEvent event ) { mSavedMatrix . set ( mMatrix ) ; mTouchStartPoint . set ( event . getX ( ) , event . getY ( ) ) ; mClosestDataSetToTouch = mChart . getDataSetByTouchPoint ( event . getX ( ) , event . getY ( ) ) ; }
target:  Saves the current Matrix state and the touch-start point.