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