add fixed point procedure for better reflow performance
add fixed point procedure for better reflow performance

ashang/koreader,poire-z/koreader,pazos/koreader,mwoz123/koreader,ashhher3/koreader,koreader/koreader,Frenzie/koreader,chrox/koreader,koreader/koreader,lgeek/koreader,NiLuJe/koreader,Markismus/koreader,houqp/koreader,Hzj-jie/koreader,Frenzie/koreader,chihyang/koreader,NiLuJe/koreader,NickSavage/koreader,robert00s/koreader,apletnev/koreader,noname007/koreader,mihailim/koreader,poire-z/koreader,frankyifei/koreader