Modifying Colors in rst.el

Question

In Emacs, I'm using a color scheme with a dark background and light text. When working with .rst files, I have a mode for that which uses rst.el. However, rst.el highlights headings with a light background color, which makes reading light text on it impossible!

I think that this is the section of code in rst.el that is responsible for the background colors:

(defgroup rst-faces-defaults nil
  "Values used to generate default faces for section titles on all levels.
Tweak these if you are content with how section title faces are built in
general but you do not like the details."
  :group 'rst-faces
  :version "21.1")

(defun rst-define-level-faces ()
  "Define the faces for the section title text faces from the values."
  ;; All variables used here must be checked in `rst-set-level-default'
  (let ((i 1))
    (while (<= i rst-level-face-max)
      (let ((sym (intern (format "rst-level-%d-face" i)))
        (doc (format "Face for showing section title text at level %d" i))
        (col (format ("gray10")))
    (make-empty-face sym)
    (set-face-doc-string sym doc)
    (set-face-background sym col)
    (set sym sym)
    (setq i (1+ i))))))

(defun rst-set-level-default (sym val)
  "Set a customized value affecting section title text face and recompute the
faces."
  (custom-set-default sym val)
  ;; Also defines the faces initially when all values are available
  (and (boundp 'rst-level-face-max)
       (boundp 'rst-level-face-format-light)
       (boundp 'rst-level-face-base-color)
       (boundp 'rst-level-face-step-light)
       (boundp 'rst-level-face-base-light)
       (rst-define-level-faces)))

;; Faces for displaying items on several levels; these definitions define
;; different shades of grey where the lightest one (i.e. least contrasting) is
;; used for level 1
(defcustom rst-level-face-max 6
  "Maximum depth of levels for which section title faces are defined."
  :group 'rst-faces-defaults
  :type '(integer)
  :set 'rst-set-level-default)
(defcustom rst-level-face-base-color "grey"
  "The base name of the color to be used for creating background colors in
ection title faces for all levels."
  :group 'rst-faces-defaults
  :type '(string)
  :set 'rst-set-level-default)
(defcustom rst-level-face-base-light
  (if (eq frame-background-mode 'dark)
      85
    15)
  "The lightness factor for the base color. This value is used for level 1. The
default depends on whether the value of `frame-background-mode' is `dark' or
not."
  :group 'rst-faces-defaults
  :type '(integer)
  :set 'rst-set-level-default)
(defcustom rst-level-face-format-light "%2d"
  "The format for the lightness factor appended to the base name of the color.
This value is expanded by `format' with an integer."
  :group 'rst-faces-defaults
  :type '(string)
  :set 'rst-set-level-default)
(defcustom rst-level-face-step-light
  (if (eq frame-background-mode 'dark)
     -7
     7)
  "The step width to use for the next color. The formula

    `rst-level-face-base-light'
    + (`rst-level-face-max' - 1) * `rst-level-face-step-light'

must result in a color level which appended to `rst-level-face-base-color'
using `rst-level-face-format-light' results in a valid color such as `grey50'.
This color is used as background for section title text on level
`rst-level-face-max'."
  :group 'rst-faces-defaults
  :type '(integer)
  :set 'rst-set-level-default)

(defcustom rst-adornment-faces-alist
  (let ((alist '((t . font-lock-keyword-face)
         (nil . font-lock-keyword-face)))
    (i 1))
    (while (<= i rst-level-face-max)
      (nconc alist (list (cons i (intern (format "rst-level-%d-face" i)))))
      (setq i (1+ i)))
    alist)
  "Provides faces for the various adornment types. Key is a number (for the
section title text of that level), t (for transitions) or nil (for section
title adornment). If you generally do not like how section title text faces are
set up tweak here. If the general idea is ok for you but you do not like the
details check the Rst Faces Defaults group."
  :group 'rst-faces
  :type '(alist
      :key-type
      (choice
       (integer
        :tag
        "Section level (may not be bigger than `rst-level-face-max')")
       (boolean :tag "transitions (on) / section title adornment (off)"))
      :value-type (face))
  :set-after '(rst-level-face-max))

I've tried changing 'grey' to something else, but it doesn't change a thing. Any help?

Answer 1

M-x customize-group rst-faces

If you insist on using code, then use customize to set some things, look at the generated code and use it as a model. However, it's no longer considered good form to do it with old-fashioned .emacs code.