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Re: VSCode or Vim ports of the Emacs modus-themes?

Notes on possible ports of the modus-operandi and modus-vivendi themes to text editors or other platforms

The following is a frequently asked question, though I realise I have never addressed it on my website. I am reproducing my reply with permission, without divulging the identity of my correspondent. I will also include such information in the themes’ manual.

As always, feel welcome to contact me for further information.


I was wondering if there are any plans to port your theme to other editors? Or is there a possibility to make a rough guideline as an orientation for people who want to port the theme? From the source code alone I had trouble identifying which color a variable, function etc. would have.

There is no plan to do this in the foreseeable future because I only use Emacs and cannot maintain ports for other editors. I can provide a quick-and-dirty simulacrum if you give me a template, but that is not how I maintain the project: the details matter greatly (I can elaborate at length if you need specific examples, but I won’t do that here in the interest of brevity).

Each program has its own requirements so it won’t always be possible—or indeed desirable—to have 1:1 correspondence between what applies to Emacs and what should be done elsewhere. I think no port should ever strive to be a faithful copy of the Emacs implementation but instead try to follow the spirit of the design. In other words, if something must be done differently on Vim/VSCode then that is okay so long as (i) the accessibility standards are not compromised and (ii) the overall character of the themes remains consistent.

The former criterion should be crystal clear as it pertains to the scientific foundations of the themes: high legibility and taking care of the needs of users with red-green colour deficiency (deuteranopia) by avoiding red+green colour coding paradigms and/or by providing red+blue variants.

The latter criterion is the je ne sais quoi of the artistic aspect of the themes: in the manual I provide insights in the “Frequently Asked Questions”, but I can expand further if you need specific guidance. In the meantime, either evaluate this from inside Emacs:

(info "(modus-themes) Frequently Asked Questions")

Or visit: https://protesilaos.com/emacs/modus-themes#h:b3384767-30d3-4484-ba7f-081729f03a47.

With regard to the artistic aspect (where “art” qua skill may amount to an imprecise science), I understand this is not a hard-and-fast rule as it requires one to exercise discretion and make decisions based on context-dependent information or constraints. As is true with most things in life, when in doubt, do not cling on to the letter of the law but try to understand its spirit.

For a trivial example: the curly underline that Emacs draws for spelling errors is thinner than, e.g., what Firefox/Chromium has, so if I was to design for an editor than has a thicker curly underline I would make the applicable colours less intense to counterbalance the typographic intensity of the added thickness.

You ask about colour mapping. I will answer though I must seize this opportunity to stress the fact that a theme is not a colour scheme. A “colour scheme” is what terminal emulators implement, where you can tweak the first 16 escape sequences and then each CLI program will make its own decisions on what to use, to the effect that you are virtually powerless to enforce consistency. As such, a theme is characterised by what the semantics of the word suggest: “thematic consistency”.

Consistency is not an alias for uniformity. Again, we need to exercise judgement based on the specifics of each case. To make this insight relatable, consider a definition of discrimination:

  • The treatment of substantially different magnitudes as if they were of the same class.
  • Or the treatment of the same class of magnitudes as if they were of a different class.

(To treat similar things differently; to treat different things alike.)

Same for producing a theme. If you enforce uniformity without accounting for the particular requirements of each context, you are making a not-so-obvious error of treating different cases as if they were the same.

This is, by the way, why I always try to use the packages that the modus-themes support instead of just applying colours on a whimsy.

With those granted, a visual method to get information on the applicable colours is to use M-x list-faces-display. This will produce a list with two columns. The first has the name of each “face” (construct that holds colour- and text- related attributes). The second shows a preview of its style. You can then click on, e.g., font-lock-builtin-face to see what foreground colour it uses. To save you from the trouble, here is the list with all font-lock faces and their default text colour when using modus-operandi (but please remember what I wrote above):

((font-lock-warning-face . "#702f00")
 (font-lock-variable-name-face . "#00538b")
 (font-lock-type-face . "#005a5f")
 (font-lock-string-face . "#2544bb")
 (font-lock-regexp-grouping-construct . "#8b1030")
 (font-lock-regexp-grouping-backslash . "#654d0f")
 (font-lock-preprocessor-face . "#a0132f")
 (font-lock-negation-char-face . "#813e00")
 (font-lock-keyword-face . "#5317ac")
 (font-lock-function-name-face . "#721045")
 (font-lock-doc-face . "#2a486a")
 (font-lock-constant-face . "#0000c0")
 (font-lock-comment-face . "#505050")
 (font-lock-builtin-face . "#8f0075"))

I got it with this code (will refine it to be more useful as this is just a sample (some faces have a :background attribute, or :inherit from another face, and so on)):

(defvar modus-themes-font-lock-color-map nil)

(dolist (face '( font-lock-builtin-face font-lock-comment-face
                 font-lock-constant-face font-lock-doc-face
                 font-lock-function-name-face font-lock-keyword-face
                 font-lock-negation-char-face font-lock-preprocessor-face
                 font-lock-regexp-grouping-backslash
                 font-lock-regexp-grouping-construct
                 font-lock-string-face font-lock-type-face
                 font-lock-variable-name-face font-lock-warning-face))
  (push (cons face (face-attribute face :foreground))
        modus-themes-font-lock-color-map))

Lastly, to get information on what face the character at point uses, invoke the command describe-char either via M-x or with the key binding C-u C-x =. It will produce a Help buffer that contains information towards the end of the content on what the applicable face is, if any.

If you plan to develop a port, I am always willing to help you whenever you have any doubts on how to tackle a specific problem. Just contact me and we will make it happen.