winheight() and winwidth() return the number of columns/lines in the current window. What I'm looking for is something closer to the actual height and width of the editing area, or displayed area if run in a terminal. The problem with winheight() and winwidth() is that aspect ratio calculated from these values is out of touch with the actual aspect ratio.

:echo winwidth('%') winheight('%') winwidth('%') * 1.0 / winheight('%')
104 51 2.039216

A screenshot of the buffer area is sized 936x918 pixels, giving a displayed aspect ratio of 1.019608. I think I can get the actual value by using the size of the font, but how?

This is a follow-up to How can I make Vim open help in a vertical split?. I'm trying to adapt Nobe4's solution.

  • 3
    I don't think you can get dimensions in pixels with plain Vim functions. As for opening help in a vertical split, I don't bother with aspect ratio calculations, I just split vertically if the terminal window is wide enough: cnoreabbrev h <C-r>=(&columns >= 160 && getcmdtype() ==# ':' && getcmdpos() == 1 ? 'vertical botright help' : 'h')<CR>. Oct 16, 2015 at 4:36
  • 1
    @SatoKatsura thus following the tradition set by most web developers, who use the document width to determine if it's a mobile. :(
    – muru
    Oct 16, 2015 at 4:39
  • 1
    Not really, since I'm only inflicting that to myself. I played with aspect ratio for a while and I found the results to be unsatisfactory. Then I remembered I have exactly two shortcuts for opening terminals, for "normal" size, and for "wide" terminals. So my terminals almost always have the same sizes. YMMV of course. Oct 16, 2015 at 4:43
  • @SatoKatsura that command is some serious dark magic. I am very surprised that aside from not knowing about the ==# operator which :h helped clear up I actually understood the entire freaking command. Does that make me a Vim expert? Gotta be something like that. Need to get out more.
    – Steven Lu
    Apr 5, 2016 at 2:20

1 Answer 1


104 columns / 51 lines = 2.04

Your calculation is skewed because the aspect ratio of each cell is vertical.

For example on Terminal.app, with 23pt font and default character spacing, each terminal cell have a width of 7px and a height of 15px for a total of 728x765px:

(104 * 7) / (51 * 15) = 728 / 765 = 0.95

You cannot retrieve the font size from within Vim without invoking external commands or a way of communicating with the terminal, which can become pretty heavy. Obviously, this is different in Gvim thanks to 'guifont'.

If you manage to do it, still you need a way to deduct the size of a cell which may vary depending on the terminal program if there is no standard. I only checked iTerm 2 which luckily have the same result.

Therefore I would opt for a static solution. I grafted the minimum width check to this snippet you could place in plugin/help.vim:

function! Help(...)
  let l:topic = a:0 ? a:1 : ''
  if winwidth('%') >= 160 " Minimum width
    execute 'vertical botright help' l:topic
    execute 'vertical resize 78'
    execute 'botright help' l:topic

" Use :H to open a vertical or horizontal help split
command! -complete=help -nargs=? H call Help(<f-args>)

If the window is large enough to keep 80 columns of the current buffer, a narrow help split is opened on the right, otherwise the split is opened below. You can customize the split direction with :vertical.

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