A command for toggling between text colours

Question

How might one write a command that toggles between the settings hi Normal ctermfg=8 and hi Normal ctermfg=12 ?

Answer 1

I think you could add this code to your $MYVIMRC file :

nnoremap <leader>t :call ToggleForegroundColor()<CR>

function! ToggleForegroundColor()

let fgcolor=synIDattr(hlID('Normal'), 'fg#')

if fgcolor == 8
    hi Normal ctermfg=12
else
    hi Normal ctermfg=8
endif

endfunction

After saving and sourcing it, you should be able to toggle between the two values by pressing <leader>t.
If your <leader> is the comma key, it would be ,t.

You can define your <leader> key in your $MYVIMRC file with something like this :

let mapleader = ","

To explain the code :

nnoremap <leader>t :call ToggleForegroundColor()<CR>

This line maps <leader>t to a function called ToggleForegroundColor. The function is defined just afterwards and is responsible for toggling the value of the ctermfg argument.

let fgcolor=synIDattr(hlID('Normal'), 'fg#')

This line assigns to the variable fgcolor the value of the foreground color number of the Normal highlight group (ctermfg if you're inside a terminal, guifg if you're inside gvim).

For more information about the built-in functions used here, you can have a look inside the help : :h synIDattr and :h hlID.

The rest of the code is a simple if else endif structure which tests the value of fgcolor to change the value of ctermfg accordingly.