ctermbg and ctermfg are backwards or incorrect for certain highlighting groups

Question

I am currently attempting to create a custom colorscheme for vim by using ctermfg and ctermbg values, and checking what the colorscheme looks like with the highlight test file provided by Vim.

What I do not understand is why ctermfg and ctermbg appear backwards, and also incorrect, for certain highlighting groups. StatusLine, for instance, is set to have a black foreground and a white background, but instead has a white foreground and a gray background. Is there something special about specific highlighting groups that I should keep in mind when I set their colors?

Answer 1

You're probably overlooking the additional attributes set in the cterm= field for those highlights.

For instance, after I set ctermfg=black ctermbg=white for StatusLine, I get this when I query it:

:hi StatusLine
StatusLine     xxx term=bold,reverse cterm=bold,reverse
                   ctermfg=0 ctermbg=15 gui=bold,reverse

You'll see the cterm=bold,reverse there, which is part of the defaults for StatusLine. In particular, reverse will swap fg & bg colors, which is the effect you're seeing.

Since those attributes are set in a separate field (cterm=), which you're not overriding, the defaults are being preserved.

To undo the effects of this field, you could set it explicitly, with:

hi StatusLine cterm=bold

Or, to also drop the bold attribute:

hi StatusLine cterm=reverse

Or you could just decide to embrace the default of using reverse colors on the StatusLine and perhaps some other highlight groups and just set your fg & bg colors in reverse, to then have the reversing applied by cterm= get the colors as you actually want them. 🙃

Also consider the term= (for B&W terminals) and gui= (for gvim) attributes, if you're considering setting custom highlighting that you'd like to work on those environments as well.