diff --git a/autoload/gitgutter/hunk.vim b/autoload/gitgutter/hunk.vim
index fc4328f..68517d0 100644
--- a/autoload/gitgutter/hunk.vim
+++ b/autoload/gitgutter/hunk.vim
@@ -64,7 +64,7 @@ function! gitgutter#hunk#next_hunk(count) abort
         if g:gitgutter_show_msg_on_hunk_jumping
           redraw | echo printf('Hunk %d of %d', index(hunks, hunk) + 1, len(hunks))
         endif
-        if s:is_preview_window_open()
+        if gitgutter#hunk#is_preview_window_open()
           call gitgutter#hunk#preview()
         endif
         return
@@ -95,7 +95,7 @@ function! gitgutter#hunk#prev_hunk(count) abort
         if g:gitgutter_show_msg_on_hunk_jumping
           redraw | echo printf('Hunk %d of %d', index(hunks, hunk) + 1, len(hunks))
         endif
-        if s:is_preview_window_open()
+        if gitgutter#hunk#is_preview_window_open()
           call gitgutter#hunk#preview()
         endif
         return
@@ -249,7 +249,7 @@ function! s:hunk_op(op, ...)
       let hunk_diff = join(hunk_header + hunk_body, "\n")."\n"
 
       call s:goto_original_window()
-      call s:close_hunk_preview_window()
+      call gitgutter#hunk#close_hunk_preview_window()
       call s:stage(hunk_diff)
     endif
 
@@ -427,7 +427,7 @@ endfunction
 function! s:open_hunk_preview_window()
   if g:gitgutter_preview_win_floating
     if exists('*nvim_open_win')
-      call s:close_hunk_preview_window()
+      call gitgutter#hunk#close_hunk_preview_window()
 
       let buf = nvim_create_buf(v:false, v:false)
       " Set default width and height for now.
@@ -446,9 +446,9 @@ function! s:open_hunk_preview_window()
       call nvim_buf_set_name(buf, 'gitgutter://hunk-preview')
 
       " Assumes cursor is in original window.
-      autocmd CursorMoved <buffer> ++once call s:close_hunk_preview_window()
+      autocmd CursorMoved <buffer> ++once call gitgutter#hunk#close_hunk_preview_window()
       if g:gitgutter_close_preview_on_escape
-        nnoremap <buffer> <silent> <Esc> :<C-U>call <SID>close_hunk_preview_window()<CR>
+        nnoremap <buffer> <silent> <Esc> :<C-U>call gitgutter#hunk#close_hunk_preview_window()<CR>
       endif
 
       return
@@ -584,7 +584,7 @@ function! s:goto_original_window()
 endfunction
 
 
-function! s:close_hunk_preview_window()
+function! gitgutter#hunk#close_hunk_preview_window()
   let bufnr = s:winid != 0 ? winbufnr(s:winid) : s:preview_bufnr
   call setbufvar(bufnr, '&modified', 0)
 
@@ -602,7 +602,7 @@ endfunction
 
 
 " Only makes sense for traditional, non-floating preview window.
-function s:is_preview_window_open()
+function gitgutter#hunk#is_preview_window_open()
   for i in range(1, winnr('$'))
     if getwinvar(i, '&previewwindow')
       return 1
diff --git a/doc/gitgutter.txt b/doc/gitgutter.txt
index 05bd2ce..233ede3 100644
--- a/doc/gitgutter.txt
+++ b/doc/gitgutter.txt
@@ -190,6 +190,12 @@ Commands for operating on a hunk:~
                         the original window with |CTRL-W_p|.  Alternatively set
                         |g:gitgutter_close_preview_on_escape| and use <Esc>.
 
+                        Two functions are available for your own logic:
+>
+                          gitgutter#hunk#is_preview_window_open()
+                          gitgutter#hunk#close_hunk_preview_window()
+<
+
 Commands for folds:~
 
                                                      *gitgutter-:GitGutterFold*