不算的

To double a player’s life total, that player gains as much life as needed so that their life total is twice the number it was before. If their life total was negative, that player loses as much life as needed so that their life total is twice as far below 0 as it was before. Other effects interact with this life gain or loss accordingly.

算的，加倍就是加血加到两倍这么多

只要不是0或负血就算

只要血量发生改变就算＂获得＂／＂失去＂生命。
比如某张牌把你的生命变成20，如果你之前血量少于20这次结算就是＂获得生命＂，会触发一切＂当你获得生命时＂的异能。如果对面有使你无法获得生命的异能存在，那么你在低于20生命时，变成20生命这个异能就无法结算。