Combining eborisch's answer with some other answers I found here and things I had to work around, I came up with the following two-part solution:
This first part makes it easier to edit text with long lines:
" Allow enabling by running the command ":Freeform", or <leader>sw
command! Softwrap :call SetupSoftwrap()
map <Leader>sw :call SetupSoftwrap() <CR>
func! SetupFreeform()
" Use setlocal for all of these so they don't affect other buffers
" Enable line wrapping.
setlocal wrap
" Only break at words.
setlocal linebreak
" Turn on spellchecking
setlocal spell
" Make jk and 0$ work on visual lines.
nnoremap <buffer> j gj
nnoremap <buffer> k gk
nnoremap <buffer> 0 g0
nnoremap <buffer> $ g$
" Disable colorcolumn, in case you use it as a column-width indicator
" I use: let &colorcolumn = join(range(101, 300), ",")
" so this overrides that.
setlocal colorcolumn=
" cursorline and cursorcolumn don't work as well in wrap mode, so
" you may want to disable them. cursorline highlights the whole line,
" so if you write a whole paragraph on a single line, the whole
" paragraph will be highlighted. cursorcolumn only highlights the actual
" column number, not the visual line, so the highlighting will be broken
" up on wrapped lines.
setlocal nocursorline
setlocal nocursorcolumn
endfunc
With this alone you can get decent text wrapping for writing something like markdown, or a Readme.
As noted in other answers, getting wrapping at an exact column width requires telling vim exactly how many columns there are, and overwriting that each time vim gets resized:
command! -nargs=? Draft :call SetupDraftMode(<args>)
func! SetupDraftMode()
" I like 80 columns + 4 for line numbers
set columns=84
autocmd VimResized * if (&columns > 84) | set columns=84 | endif
:Softwrap
endfunc
There are still a couple of problems with this:
- vim won't clear the screen outside of the columns you specify after calling set columns, and I can't figure out how to tell it to, so ideally you should call this immediately after opening vim
- vim shows a prompt with the version number and some helpful commands when you open it, so these won't be cleared. You can add
set shm+=I
to disable that prompt
- You can't open any vertical splits, because then both splits will be ~40 column. You would need to set columns to 2x your desired width and then always have a split open.
- My vimscript is awful, but ideally someone could modify the
Draft
function above to take a column width as an argument, or use a global variable (g:explicit_vim_width
?) that can be set manually if your window size changes.