Emacs FAQ on Screen Display Issues

Use the menu “Options‣Active Region Highlighting”, then “Options‣Save Options”. The equivalent command is transient-mark-mode. To have it always on, put this code: “(transient-mark-mode t)” in your emacs customization file. (“~/.emacs”)

Use the menu “Options‣Syntax Highlighting”. If you always want this feature, then do “Options‣Save Options”. To turn it for the current file only, do “Alt+x font-lock-fontify-buffer”.

Use the menu: “Options‣Set Font”, then “Options‣Save Options”.

“Alt+x line-number-mode”. To always have it on, place the following in your emacs customization file:

(defun my-turn-on-line-number-mode () (line-number-mode 1))
(add-hook 'text-mode-hook 'my-turn-on-line-number-mode)

“Alt+x column-number-mode”. To always have it on, put the following code in your “~/.emacs” file: “(column-number-mode t)”.

Use “Alt+x longlines-mode”, available in Emacs version 22. When this mode is on, lines will be wrapped at 72 chars length. To adjust the this margin, use “Alt+x set-variable”, and set fill-column a desired value.

To always have longlines-mode mode on, put in your emacs customization file: “(add-hook 'text-mode-hook (lambda () (longlines-mode t)))”.

Note: as of emacs 22 (released in mid 2007), longlines-mode is buggy, especially when you paste text.

Use the menu “Options‣Truncate Long Lines in this Buffer”. To do this without GUI, type: “Alt+set-variable RET truncate-lines RET nil”. To get it back, set truncate-lines to t.

You can put the following code in your emacs customization file (~/.emacs) so that pressing the F7 key will toggle the state.

(defun toggle-truncate-lines ()
"Toggle the variable truncate-lines between true and false"
(interactive) 
   (if (eq truncate-lines 't) 
     (set-variable 'truncate-lines nil)
     (set-variable 'truncate-lines 't)
    )
  )
(global-set-key (kbd "<f7>") 'toggle-truncate-lines)

Type “Alt+x setq-default”, then set line-spacing with value 4. This will set line-spacing to 4 pixels. You can also use a decimal. If you set line-spacing to 0.4, then it means the line spacing will be 40% of normal line height.

You can put the following elisp code in your emacs customization file to make life simpler.

(defun toggle-line-spacing ()
"Toggle line spacing between 1 and 5 pixels."
(interactive)
(if (eq line-spacing 1)
  (setq-default line-spacing 5)
  (setq-default line-spacing 1))
)
(global-set-key (kbd "<f7>") 'toggle-line-spacing)

With the above code, pressing F7 will toggle line spacing to small and large. This is useful for example, when you often switch between coding and novel reading.

Type “Alt+q” (fill-paragraph) will reformat the current block of text your cursor is on. Type “Alt+x fill-region” to reformat a selection of text. To have lines automatically cut as you type, use auto-fill-mode.

You can set the width used in the above commands. Type “Alt+x set-variable”, then given variable “fill-column”.

Note: these commands actually insert newline characters into your file. This type of wrapping is called hard-wrap. Hard-wrap for display purposes should be avoided. See: The Harm of hard-wrapping Lines.

There is no built-in function for this purpose directly. However, you can do it by setting the fill-column variable to a large value and use the line reformatting commands fill-paragraph or fill-region to reformat it.

Here are 2 elisp code that does the above. One of them has “Alt+Shift+q” as the shortcut.

(defun remove-hard-wrap-paragraph () 
  "Replace newline chars in current paragraph by single spaces."
  (interactive) 
  (let ((fill-column 90002000)) 
    (fill-paragraph nil)))

(defun remove-hard-wrap-region (start end)
  "Replace newline chars in region by single spaces." 
  (interactive "r")
  (let ((fill-column 90002000)) 
    (fill-region start end)))

(global-set-key (kbd "M-Q") 'remove-hard-wrap-paragraph)