vim cui scrollbar

cui_scrollbar.vim

" require: term.vim
" http://www.vim.org/scripts/script.php?script_id=2812

autocmd CursorMoved,CursorMovedI * call s:update_scrollbar_absolute()

" how to get curwin->w_winrow and curwin->w_wincol?
function! s:update_scrollbar_absolute()
  let winline = winline()
  let wincol = wincol()
  let winwidth = &columns
  let winheight = &lines
  let line = line('.') + 0.0
  let lastline = line('$') + 0.0
  let percent = float2nr(((line - 1) / lastline) * winheight)
  let barheight = float2nr(ceil(winheight / lastline))
  call term#save_cursor()
  for i in range(winheight)
    call term#put(i + 1, winwidth, ' ', (percent <= i && i < percent + barheight) ? 45 : 44)
  endfor
  call term#attr()
  call term#restore_cursor()
  call term#out()
endfunction

" buggy
function! s:update_scrollbar_relative()
  " XXX: Since cursor is not drawn yet, update cursor.
  redraw
  let winline = winline()
  let wincol = wincol()
  let winwidth = winwidth(0)
  let winheight = winheight(0)
  let line = line('.') + 0.0
  let lastline = line('$') + 0.0
  let percent = float2nr(((line - 1) / lastline) * winheight)
  let barheight = float2nr(ceil(winheight / lastline))
  call term#save_cursor()
  call term#preceding_line(winline - 1)
  for i in range(winheight)
    call term#forward(winwidth - 1)
    call term#text(' ', (percent <= i && i < percent + barheight) ? 45 : 44)
    call term#next_line()
  endfor
  call term#attr()
  call term#restore_cursor()
  call term#out()
endfunction