perfect-margin

Perfect-margin is a global minor mode to auto center windows, work with minimap and/or linum-mode.

A picture is more than one thousand words, here is how it looks like with minimap and linum-mode.

theme: doom-dracula from beautiful doom-themes

minimap from MELPA

Usage

Put perfect-margin under your Emacs load path, and add this to your init.el

(require 'perfect-margin)

Use M-x perfect-margin-mode to turn on/off perfect-margin.

To make it permanent add this to your init.el after require.

(perfect-margin-mode 1)

Important Note

when using together with minimap or linum, make sure you place config for perfect-margin AFTER minimap and linum.

Customization

Via M-x customize-group and enter perfect-margin.

Change perfect-margin-visible-width and Apply and Save. That's it.

Or you can change the visible window width by setup perfect-margin-visible-width on the init.el.

(setq perfect-margin-visible-width 128)

Customize what window to ignore setting margins

perfect-margin by default ignore setting margins for minibuffer window and any window whos name starts with "*". Many of them are for special purpose.

You can change this behavior by setting perfect-margin-ignore-regexps and perfect-margin-ignore-filters.

(defcustom perfect-margin-ignore-regexps
  '("^minibuf" "^[*]")
  "List of strings to determine if window is ignored.
Each string is used as regular expression to match the window buffer name."
  :group 'perfect-margin)

(defcustom perfect-margin-ignore-filters
  '(window-minibuffer-p)
  "List of functions to determine if window is ignored.
Each function is called with window as its sole arguemnt, returning a non-nil value indicate to ignore the window."
  :group 'perfect-margin)

Additional binding on margin area

You can place this in your init.el to make mouse wheel scroll on margin area just like it scroll on the visible window.

(dolist (margin '("<left-margin> " "<right-margin> "))
  (global-set-key (kbd (concat margin "<mouse-1>")) 'ignore)
  (global-set-key (kbd (concat margin "<mouse-3>")) 'ignore)
  (dolist (multiple '("" "double-" "triple-"))
      (global-set-key (kbd (concat margin "<" multiple "wheel-up>")) 'mwheel-scroll)
      (global-set-key (kbd (concat margin "<" multiple "wheel-down>")) 'mwheel-scroll)))

for use-package user

(use-package perfect-margin
  :custom
  (perfect-margin-visible-width 128)
  :config
  ;; enable perfect-mode
  (perfect-margin-mode t)
  
  ;; add additinal bding on margin area
  (dolist (margin '("<left-margin> " "<right-margin> "))
  (global-set-key (kbd (concat margin "<mouse-1>")) 'ignore)
  (global-set-key (kbd (concat margin "<mouse-3>")) 'ignore)
  (dolist (multiple '("" "double-" "triple-"))
      (global-set-key (kbd (concat margin "<" multiple "wheel-up>")) 'mwheel-scroll)
      (global-set-key (kbd (concat margin "<" multiple "wheel-down>")) 'mwheel-scroll))))

Emacs Rocks and happy hacking!