private void saveTouchStart(MotionEvent event){
  mSavedMatrix.set(mTouchMatrix);
  mTouchStartPoint.x=event.getX();
  mTouchStartPoint.y=event.getY();
  mClosestDataSetToTouch=mChart.getDataSetByTouchPoint(event.getX(),event.getY());
}

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