How to setup in `~/.vimrc` a mapping for `colorscheme` to toggle `solarized` between `dark` and `light`?

Question

Both background and colorscheme in ~/.vimrc are badly misbehaving!

I have setup solarized to work on vim and it can manually toggle between background light/dark. My general settings in ~/.vimrc are:

Plug 'altercation/vim-colors-solarized' "I use plug.vim
syntax enable
set background=light
set t_Co=256
let g:solarized_termcolors=256

Operating system: Ubuntu 14.04.; xterm and works well with 256 colors.

I'm trying to map in ~/.vimrc background toggling. For this purpose :help solarized (in vim) suggests to use:

call togglebg#map("<F9>")

but this doesn't work because it changes the colorscheme from solarized to default (my intention was to toggle only in solarized between dark and light).

So I remove from ~/.vimrc call togglebg#map("<F9>") and replaced it with what most google/superuser/vim.wikia commentators, in various flavors, have suggested with the following:

function! BgToggleSol()
    if (&background == "light")
      set background=dark 
    else
       set background=light 
    endif
endfunction

nnoremap <silent> <leader>sz :call BgToggleSol()<cr>

colorscheme solarized

But this has the same problem (that toggling resets colorscheme to default). While if colorscheme solarized is executed directly after set background=... in the if else endif clause then the background stops toggling between dark/light.

I must have exhausted nearly all possibilities, but the problem is still not going away.

Any suggestion is very welcome. Thanks in advance.

Answer 1

Something is definitely not right. I have in my .vimrc something like this:

set background=dark
colorscheme solarized

And when I do :set bg? after that, it shows "light". I think that's the reason the if/else/endif in you function doesn't work after 'colorsheme solarized'.

The only workaround I can think of is to maintain the state in a separate variable:

" Initially set it to "dark" or "light" according to your default
let s:mybg = "dark"
function! BgToggleSol()
    if (s:mybg ==? "light")
       set background=dark
       let s:mybg = "dark"
    else
       set background=light
       let s:mybg = "light"
    endif
    " set background=light
    colorscheme solarized
endfunction

nnoremap <silent> <leader>sz :call BgToggleSol()<cr>

Answer 2

You might want something like:

map <Leader>bg :let &background = ( &background == "dark"? "light" : "dark" )<CR>

This toggles between dark and light. Leader's default, if not set otherwise, is \.

Btw you can also do so with colorschemes:

map <Leader>cs :execute ( g:colors_name == "selenized_bw" ? "colorscheme selenized" : "colorscheme selenized_bw" ) <CR>

Or together:

noremap <Leader>bg :let &background = ( &background == "dark" ? "light" : "dark" )<CR> <bar> :execute ( g:colors_name == "selenized_bw" ? "colorscheme selenized" : "colorscheme selenized_bw" ) <CR>

Answer 3

Here's an alternative two parter answer, that toggles both the colorscheme and the background. First, using your mapping, then a specific mapping pattern I use to mirror another popular plugin with many provided toggles.

This mapping toggles both the background to light or dark, and the colorscheme, using printf.

1. I'll use your <leader>sz mapping here:

   nnoremap <silent><expr><leader>sz printf(":set bg=%s \| colo %s\r", &bg ==# 'dark' ? 'light' : 'dark', &bg ==# 'dark' ? 'modest' : 'moonfly')
   

Note that this uses <expr> in addition to your <silent> and this is required since we're using printf. Read :help <expr>

2. I use tpope's vim-unpaired which advertises itself as "Pairs of handy bracket mappings" but it also provides many toggles that use a yo_ mapping.

   So I set my colorscheme toggle to use the same pattern:

   nnoremap <silent><expr>yot printf(":set bg=%s \| colo %s\r", &bg ==# 'dark' ? 'light' : 'dark', &bg ==# 'dark' ? 'modest' : 'moonfly')
   

   For some other examples of toggles, because why not, here's the list from vim-unimpaired and note that I am overwriting their colorcolumn toggle because I didn't realize it when I started using yot and evidently I never toggle that column:

   On  Off Toggle  Option
   *[ob*   *]ob*   *yob*   'background' (dark is off, light is on)
   *[oc*   *]oc*   *yoc*   'cursorline'
   *[od*   *]od*   *yod*   'diff' (actually |:diffthis| / |:diffoff|)
   *[oh*   *]oh*   *yoh*   'hlsearch'
   *[oi*   *]oi*   *yoi*   'ignorecase'
   *[ol*   *]ol*   *yol*   'list'
   *[on*   *]on*   *yon*   'number'
   *[or*   *]or*   *yor*   'relativenumber'
   *[os*   *]os*   *yos*   'spell'
   *[ot*   *]ot*   *yot*   'colorcolumn' ("+1" or last used value)
   *[ou*   *]ou*   *you*   'cursorcolumn'
   *[ov*   *]ov*   *yov*   'virtualedit'
   *[ow*   *]ow*   *yow*   'wrap'
   *[ox*   *]ox*   *yox*   'cursorline' 'cursorcolumn' (x as in crosshairs)
   

   tpope comments on why they chose y: "The mnemonic for y is that if you tilt it a bit it looks like a switch."