Question

Inside just one lonely emacs frame I switch frequently between editting 70-column text files (LaTeX) and 120-column programs (.h/.cpp files). I’d like to continue to use just one emacs frame, without resizing it or creating additional frames.

Here is the problem. The width of my window is about right for editting the 120-column programs, but during the extended text editting sessions, the 70 columns appear on the left side of the window. At the end of the day in front of a laptop, my neck seems to have acquired a semi-permanent tilt to the left.

Are you aware of a method to make the text appear centered, while still making the text files remain jagged on the right?

Answer 1

You could try narrowing the frame by increasing the fringe size. For example:

(set-fringe-style '(200 . 200))

would shave 200 pixels off each side of the main text area, leaving the work area 400 pixels narrower but still centered. To return to the regular view,

(set-fringe-style 'default)

will revert the fringe to the normal size.

And you can wrap that up inside some advice, which might work well for you if you stick to using just a single window:

(defadvice switch-to-buffer (after switch-to-buffer-adjust-fringe activate)
  "depending on major mode, switch fringe style"
  (if (memq major-mode '(latex-mode))
  (set-fringe-style '(200 . 200))
(set-fringe-style 'default)))

Note: Update the list (latex-mode) to contain whatever modes you want to have the large fringes.