In the previous section we documented how one can override color values
manually (Override colors). Here we use a programmatic approach which
leverages the built-in color-saturate-name function to adjust the
saturation of all color values used by the active Modus theme. Our goal
is to prepare a counterpart of the active theme’s palette that holds
modified color values, adjusted for a percent change in saturation. A
positive number amplifies the effect, while a negative one will move
towards a grayscale spectrum.
We start with a function that can be either called from Lisp or invoked
interactively. In the former scenario, we pass to it the rate of change
we want. While in the latter, a minibuffer prompt asks for a number to
apply the desired effect. In either case, we intend to assign anew the
value of modus-themes-operandi-color-overrides (light theme) and the
same for modus-themes-vivendi-color-overrides (dark theme).
(defun my-modus-themes-saturate (percent)
"Saturate current Modus theme palette overrides by PERCENT."
(interactive
(list (read-number "Saturation by percent: ")))
(let* ((theme (modus-themes--current-theme))
(palette (pcase theme
('modus-operandi modus-themes-operandi-colors)
('modus-vivendi modus-themes-vivendi-colors)
(_ (error "No Modus theme is active"))))
(overrides (pcase theme
('modus-operandi 'modus-themes-operandi-color-overrides)
('modus-vivendi 'modus-themes-vivendi-color-overrides)
(_ (error "No Modus theme is active")))))
(let (name cons colors)
(dolist (cons palette)
(setq name (color-saturate-name (cdr cons) percent))
(setq name (format "%s" name))
(setq cons `(,(car cons) . ,name))
(push cons colors))
(set overrides colors))
(pcase theme
('modus-operandi (modus-themes-load-operandi))
('modus-vivendi (modus-themes-load-vivendi)))))
;; sample Elisp calls (or call `my-modus-themes-saturate' interactively)
(my-modus-themes-saturate 50)
(my-modus-themes-saturate -75)
Using the above has an immediate effect, as it reloads the active Modus theme.
The ‘my-modus-themes-saturate’ function stores new color values in the
variables modus-themes-operandi-color-overrides and
modus-themes-vivendi-color-overrides, meaning that it undoes changes
implemented by the user on individual colors. To have both automatic
saturation adjustment across the board and retain per-case edits to the
palette, some tweaks to the above function are required. For example:
(defvar my-modus-themes-vivendi-extra-color-overrides
'((fg-main . "#ead0c0")
(bg-main . "#050515"))
"My bespoke colors for `modus-vivendi'.")
(defvar my-modus-themes-operandi-extra-color-overrides
'((fg-main . "#1a1a1a")
(bg-main . "#fefcf4"))
"My bespoke colors for `modus-operandi'.")
(defun my-modus-themes-saturate (percent)
"Saturate current Modus theme palette overrides by PERCENT.
Preserve the color values stored in
`my-modus-themes-operandi-extra-color-overrides',
`my-modus-themes-vivendi-extra-color-overrides'."
(interactive
(list (read-number "Saturation by percent: ")))
(let* ((theme (modus-themes--current-theme))
(palette (pcase theme
('modus-operandi modus-themes-operandi-colors)
('modus-vivendi modus-themes-vivendi-colors)
(_ (error "No Modus theme is active"))))
(overrides (pcase theme
('modus-operandi 'modus-themes-operandi-color-overrides)
('modus-vivendi 'modus-themes-vivendi-color-overrides)
(_ (error "No Modus theme is active"))))
(extra-overrides (pcase theme
('modus-operandi my-modus-themes-operandi-extra-color-overrides)
('modus-vivendi my-modus-themes-vivendi-extra-color-overrides)
(_ (error "No Modus theme is active")))))
(let (name cons colors)
(dolist (cons palette)
(setq name (color-saturate-name (cdr cons) percent))
(setq name (format "%s" name))
(setq cons `(,(car cons) . ,name))
(push cons colors))
(set overrides (append extra-overrides colors)))
(pcase theme
('modus-operandi (modus-themes-load-operandi))
('modus-vivendi (modus-themes-load-vivendi)))))
To disable the effect, one must reset the aforementioned variables of
the themes to nil. Or specify a command for it, such as by taking
inspiration from the modus-themes-toggle we already provide:
(defun my-modus-themes-revert-overrides ()
"Reset palette overrides and reload active Modus theme."
(interactive)
(setq modus-themes-operandi-color-overrides nil
modus-themes-vivendi-color-overrides nil)
(pcase (modus-themes--current-theme)
('modus-operandi (modus-themes-load-operandi))
('modus-vivendi (modus-themes-load-vivendi))))