How can I scroll a half page on C-v and M-v?

Question

I use Spacemacs, and for some time I've rebound C-v and M-v to spacemacs/scroll-half-page-down and spacemacs/scroll-half-page-up, respectively, to aid my understanding of the buffer as I move through it.

After a recent update, though, these functions seem to no longer be defined. How can I get them back, or something reasonably similar?

Answer 1

I actually managed to find the equivalent functions. They are

• View-scroll-half-page-forward
• View-scroll-half-page-backward

So, I've updated my dotfile's user-config section to contain

(global-set-key (kbd "C-v") 'View-scroll-half-page-forward)
(global-set-key (kbd "M-v") 'View-scroll-half-page-backward)

and this seems to work fine!

Answer 2

I personally recommend you to use a package named golden-ratio-scroll-screen. You can add melpa to your package-list if you have not.

(add-to-list 'package-archives '("melpa" . "https://melpa.org/packages/"))

and then M-x package-list-packages, search for golden-ratio-,

or go to https://github.com/jixiuf/golden-ratio-scroll-screen to get it.

It will do the following two things, which are to me excellent, maybe also what you want:

1. Scroll half screen down or up, and
2. highlight current line before or after scrolling.

Answer 3

You can also write pretty simple elisp code to achieve this :-

(defun scroll-half-page-down ()
  "scroll down half the page"
  (interactive)
  (scroll-down (/ (window-body-height) 2)))

(defun scroll-half-page-up ()
  "scroll up half the page"
  (interactive)
  (scroll-up (/ (window-body-height) 2)))

Answer 4

I use

(defun advice/scroll-context (proc &rest r)
  (let ((next-screen-context-lines (/ (window-text-height) 2)))
    (apply proc r)))

(mapc
 (lambda (sym) (advice-add sym :around #'advice/scroll-context))
 '(scroll-up scroll-down image-scroll-up image-scroll-down))

in my emacs.el profile to achive this.