Changing margin for emacs text-mode

Question

The only way I found to change margins in emacs to my liking without things acting funny is this:

(add-hook 'window-configuration-change-hook
          (lambda ()
            (set-window-margins (car (get-buffer-window-list (current-buffer) nil t)) 24 24)))

I would like for this setting to be invoked only in text-mode and change back when I change to other modes. Somewhat naively I tried this:

(add-hook 'text-mode-hook
          (lambda ()
            (set-window-margins (car (get-buffer-window-list (current-buffer) nil t)) 24 24)))

But it's not working. What would be the right code to have the margins only change for buffers in text-mode?

Answer 1

Even though you can set the margins using set-window-margins, they are lost as soon as you change the window in any way. A better solution is to set the variables left-margin-width and right-margin-width. For example:

(defun my-set-margins ()
  "Set margins in current buffer."
  (setq left-margin-width 24)
  (setq right-margin-width 24))

(add-hook 'text-mode-hook 'my-set-margins)

Answer 2

How about something like this? Your problem likely stems from the fact that many major modes inherit text-mode. You can either eliminate your window-configuration-change-hook, or you can use your new function major-briggs with it -- personally I'd just use the text-mode-hook with the major-briggs function.

(add-hook 'text-mode-hook (lambda ()
  (major-briggs)
  ;; insert additional stuff if so desired
  ))

(defun major-briggs ()
  (when (eq major-mode 'text-mode)
    (set-window-margins
      (car (get-buffer-window-list (current-buffer) nil t)) 24 24) ))