GNU ELPA: colorful-mode

• colorful-allow-mouse-clicks (default: t) If non-nil, allow using mouse buttons for change color.
• colorful-use-prefix (default: nil) If non-nil, use prefix for preview color instead highlight them.

[!WARNING]

css-mode derived modes colorize rgb and hex colors out the box, this may interfere with colorful prefix, you can disable this setting 'css-fontify-colors' to nil

• colorful-prefix-string (default: "●") String to be used in highlights.
• colorful-prefix-alignment (default: 'left) The position to put prefix string.
• colorful-extra-color-keyword-functions List of functions to add color highlighting to colorful-color-keywords.
• colorful-exclude-colors (default: '("#define")) List of keywords not to highlight.
• colorful-short-hex-conversions (default: t) If non-nil, colorful will converted long hex colors to \"#RRGGBB\" format.
• colorful-only-strings (default: nil) If non-nil, colorful will only highlight colors inside strings.
• colorful-highlight-in-comments (default: nil) If non-nil, colorful will highlight colors inside comments.
• colorful-html-colors-alist Alist of HTML colors. Each entry should have the form (COLOR-NAME . HEXADECIMAL-COLOR).
• global-colorful-modes (default: '(prog-mode help-mode html-mode css-mode latex-mode)) Which major modes global-colorful-mode is switched on in (globally).

• colorful-base Face used as base for highlight color names. Changing background or foreground color will have no effect.

• colorful-change-or-copy-color Change or copy color at point to another format.
• colorful-convert-and-change-color Convert color at point or colors in region to another format.
• colorfu-convert-and-copy-color Convert color at point to another format and copy it to the kill ring.
• colorful-mode Buffer-local minor mode.
• global-colorful-mode Global minor mode.

These key bindings are defined by: colorful-mode-map

• C-x c x → colorful-change-or-copy-color.
• C-x c c → colorful-convert-and-copy-color.
• C-x c r → colorful-convert-and-change-color.

If you want to use CSS rgb() colors outside CSS-mode derived modes, you can add them to the user-option colorful-extra-color-keyword-functions in your configuration.

(add-to-list 'colorful-extra-color-keyword-functions '(<<your-major-mode>> . colorful-add-rgb-colors))

This will add CSS's rgb highlighting to <<your-major-mode>> mode and its derived modes.

If you want to add more than one color highlighting to the same major-mode (e.g. CSS's HSL and RGB together) you can use this format:

(add-to-list 'colorful-extra-color-keyword-functions '(<<your-major-mode>> . (colorful-add-rgb-colors colorful-add-hsl-colors)))

colorful provides extra functions out-the-box that enable additional highlighting:

• colorful-add-hex-colors: Enable Hexadecimal colors highlighting.
• colorful-add-emacs-color-names-colors: Enable Emacs-specific color names highlighting. (Useful for theme creators)
• colorful-add-web-color-names-colors: Enable CSS/HTML specific color names highlighting.
• colorful-add-css-variables-colors: Enable CSS-specific user-defined color variables highlighting.
• colorful-add-rgb-colors: Enable CSS RGB colors highlighting.
• colorful-add-oklab-oklch-colors: Enable CSS OkLab and OkLch colors highlighting.
• colorful-add-hsl-colors: Enable CSS HSL colors highlighting.
• colorful-add-latex-colors: Enable LaTeX rgb/RGB/HTML/Grey colors highlighting.
• colorful-add-ansi-shell-colors: Enable ANSI shell color codes highlighting.

(See: colorful-extra-color-keyword-functions user-option for more details.)

If you want to disable colorful at region this hack may be useful for you:

(add-hook 'post-command-hook
          (lambda ()
            "delete colorful overlay on active mark"
            (when-let* (colorful-mode
                        (beg (use-region-beginning))
                        (end (use-region-end)))
              ;; Remove full colorful overlay instead only the part where
              ;; the region is.
                  (dolist (ov (overlays-in beg end))
                    (when (overlay-get ov 'colorful--overlay)
                      (delete-overlay ov))))))

(add-hook 'deactivate-mark-hook
          (lambda ()
            "refontify deleted mark"
            (when-let* (colorful-mode
                        (beg (region-beginning))
                        (end (region-end)))
              (font-lock-flush beg end))))