Users may opt to customize individual faces of the themes to accommodate
their particular needs. One such case is with the color intensity of
comments, specifically the foreground of font-lock-comment-face. The
Modus themes set that to a readable value, in accordance with their
accessibility objective, though users may prefer to lower the overall
contrast on an on-demand basis.
One way to achieve this is to design a command that cycles through three distinct levels of intensity, though the following can be adapted to any kind of cyclic behavior, such as to switch between red, green, and blue.
In the following example, we employ the modus-themes-color function
which reads a symbol that represents an entry in the active theme’s
color palette (Case-by-case face specs using the themes’ palette).
Those are stored in my-modus-themes-comment-colors.
(defvar my-modus-themes-comment-colors
;; We are abusing the palette here, as those colors have their own
;; purpose in the palette, so please ignore the semantics of their
;; names.
'((low . bg-region)
(medium . bg-tab-inactive-alt)
(high . fg-alt))
"Alist of levels of intensity mapped to color palette entries.
The entries are found in `modus-themes-operandi-colors' or
`modus-themes-vivendi-colors'.")
(defvar my-modus-themes--adjust-comment-color-state nil
"The cyclic state of `my-modus-themes-adjust-comment-color'.
For internal use.")
(defun my-modus-themes--comment-foreground (degree state)
"Set `font-lock-comment-face' foreground.
Use `my-modus-themes-comment-colors' to extract the color value
for each level of intensity.
This is complementary to `my-modus-themes-adjust-comment-color'."
(let ((palette-colors my-modus-themes-comment-colors))
(set-face-foreground
'font-lock-comment-face
(modus-themes-color (alist-get degree palette-colors)))
(setq my-modus-themes--adjust-comment-color-state state)
(message "Comments are set to %s contrast" degree)))
(defun my-modus-themes-adjust-comment-color ()
"Cycle through levels of intensity for comments.
The levels are determined by `my-modus-themes-comment-colors'."
(interactive)
(pcase my-modus-themes--adjust-comment-color-state
('nil
(my-modus-themes--comment-foreground 'low 1))
(1
(my-modus-themes--comment-foreground 'medium 2))
(_
(my-modus-themes--comment-foreground 'high nil))))
With the above, M-x my-modus-themes-adjust-comment-color will cycle through the three levels of intensity that have been specified.
Another approach is to not read from the active theme’s color palette and instead provide explicit color values, either in hexadecimal RGB notation (like ‘#123456’) or as the names that are displayed in the output of M-x list-colors-display. In this case, the alist with the colors will have to account for the active theme, so as to set the appropriate colors. While this introduces a bit more complexity, it ultimately offers greater flexibility on the choice of colors for such a niche functionality (so there is no need to abuse the palette of the active Modus theme):
(defvar my-modus-themes-comment-colors
'((light . ((low . "gray75")
(medium . "gray50")
(high . "#505050"))) ; the default for `modus-operandi'
(dark . ((low . "gray25")
(medium . "gray50")
(high . "#a8a8a8")))) ; the default for `modus-vivendi'
"Alist of levels of intensity mapped to color values.
For such colors, consult the command `list-colors-display'. Pass
the name of a color or its hex value.")
(defvar my-modus-themes--adjust-comment-color-state nil
"The cyclic state of `my-modus-themes-adjust-comment-color'.
For internal use.")
(defun my-modus-themes--comment-foreground (degree state)
"Set `font-lock-comment-face' foreground.
Use `my-modus-themes-comment-colors' to extract the color value
for each level of intensity.
This is complementary to `my-modus-themes-adjust-comment-color'."
(let* ((colors my-modus-themes-comment-colors)
(levels (pcase (car custom-enabled-themes)
('modus-operandi (alist-get 'light colors))
('modus-vivendi (alist-get 'dark colors)))))
(set-face-foreground
'font-lock-comment-face
(alist-get degree levels))
(setq my-modus-themes--adjust-comment-color-state state)
(message "Comments are set to %s contrast" degree)))
(defun my-modus-themes-adjust-comment-color ()
"Cycle through levels of intensity for comments.
The levels are determined by `my-modus-themes-comment-colors'."
(interactive)
(pcase my-modus-themes--adjust-comment-color-state
('nil
(my-modus-themes--comment-foreground 'low 1))
(1
(my-modus-themes--comment-foreground 'medium 2))
(_
(my-modus-themes--comment-foreground 'high nil))))
The effect of the above configurations on font-lock-comment-face is
global. To make it buffer-local, one must tweak the code to employ the
function face-remap-add-relative (Remap face with local value).
So this form in my-modus-themes--comment-foreground:
;; example 1 (... (set-face-foreground 'font-lock-comment-face (modus-themes-color (alist-get degree palette-colors))) ...) ;; example 2 (... (set-face-foreground 'font-lock-comment-face (alist-get degree levels)) ...)
Must become this:
;; example 1 (... (face-remap-add-relative 'font-lock-comment-face `(:foreground ,(modus-themes-color (alist-get degree palette-colors)))) ...) ;; example 2 (... (face-remap-add-relative 'font-lock-comment-face `(:foreground ,(alist-get degree levels))) ...)