isearch-filter-visible

isearch-filter-visible is a compiled Lisp function in `isearch.el'.

(isearch-filter-visible BEG END)

Test whether the current search hit is visible at least partially.
Return non-nil if the text from BEG to END is visible to Isearch as
determined by `isearch-range-invisible' unless invisible text can be
searched too when `search-invisible' is t.