Make the default behavior of split window resize consistent

Question

I use the keybinding Ctrl+W >/< to increase/decrease width of the split window, and that works just fine when the split window is in the left.

However when I switch to any split beside the one on the far left, I don't feel like this specific movement is natural because now the key binding Ctrl+W > starts to increase the current split window and vice versa .

Is there any way to make Ctrl+W >/< consistent, i.e., always increase / decrease the width of the current split irrespective of its position?

A more accurate query is a way that makes Ctrl+W >/< move the split window's vertical line right (>) or left (<) with relation to decrease / increase in width of the current split ?

Answer 1

Just a note about consistency: current behavior is consistent, increase or decrease window size. For the leftmost/rightmost windows though it is impossible to decrease/increase to the left/right due to natural constraints (terminal window/gui window) thus it does it eating space of other splits.

So back to your request, what you can do is to analyze output of winlayout function and decide what to do with the split depending on current window position.

It wouldn't be that simple, so here is the simplified example that would "work" only for a simple layout (all windows are vertically split):

func! Resize(dir, count) abort
    if winnr('$') == 1 | return | endif
    let dir = a:dir
    if winnr() == winnr('$')
        let dir = !dir
    endif
    let cmd_dir = dir ? '+' : '-'
    exe "vert resize ". cmd_dir . a:count
endfunc
nnoremap <C-w>> :<C-u>call Resize(1, v:count1)<CR>
nnoremap <C-w>< :<C-u>call Resize(0, v:count1)<CR>

Answer 2

Consider the following layout. If you are in window 2, what should ctrl-w > do? It's ambiguous regardless of whether you think > should widen the window, or move the split bar.

vim takes the following definitions: 1) > always increases the width of a window- makes it greater (>). 2) The right split is always moved unless it's impossible, in which case the left split is moved.

----------------
|    |    |    |
|  1 |  2 |  3 |
|    |    |    |
----------------

It seems that (besides the apparent reversion of < and >) the most confusing case is around the latter portion of (2), where > moves the left split to the left.

We can use the following map to handle this special case (based on Maxim Kim's suggestion).

func! Resize(dir, count) abort
    let l:dir = a:dir
    if winnr('l') == winnr()
        let l:dir = !l:dir
    endif
    execute 'vert resize' (l:dir ? '+' : '-') . a:count
endfunc
nnoremap <c-w>> :<c-u>call Resize(1, v:count1)<cr>
nnoremap <c-w>< :<c-u>call Resize(0, v:count1)<cr>