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For example, how can I make a minor mode that changes the default foreground color to gray, and upon exiting the minor mode, the foreground color is back to black? This mode might be useful when you don't like certain text to be seen over your shoulders.

For now, I run the following code to turn text color to gray:

(set-face-attribute 'default (selected-frame) :foreground "darkgrey")

And the following code to get back.

(set-face-attribute 'default (selected-frame) :foreground "SystemWindowText")

But this affects all buffers.

Drew
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Yoo
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1 Answers1

8

You can use buffer-face-mode based on overlays, it also lets to change the background of text in your buffer.

(make-face 'hard-to-read-font)
(set-face-attribute 'hard-to-read-font nil :background "darkgrey" :foreground "grey")

(define-minor-mode hard-to-read-mode
  "This mode might be useful when you don't like certain text to be seen over your shoulders."
  :init-value nil :lighter " hard-to-read" :keymap nil
  (if hard-to-read-mode
      (progn
        (font-lock-mode nil)
        (buffer-face-mode t)
        (buffer-face-set 'hard-to-read-font))
    (progn
      (font-lock-mode t)
      (buffer-face-mode nil))))

;; change this to mode you need
;; or turn it on manually
;; (add-hook 'text-mode-hook
;;           (lambda ()
;;             (hard-to-read-mode t)))

update: You know, this isn't secure. It works against human eyes, but anyone can use camera and then just increase contrast to read the text.

koddo
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