As we are working on a text editing application, that supports OpenType features for the text.
While the user is typing inside a paragraph we must do Re-analysis of the surrounding text cause of this change so the OpenType can be updated.
We want to Re-analysis as less text as we can, so the program will be fast and light. We do not want, and do not need to do all paragraph analysis again.
We will be glad to have your smart opinion on this issue - what is the less sequence of text that we must analyze according to the look behind or look ahead of the OpenType. What is the Maximum of text that open type can catch.