[UPDATED 2025] Keyboard shortcuts for color annotations in `pdf-tools` for `emacs`

.emacs

(require 'package)
(add-to-list 'package-archives '("melpa" . "https://melpa.org/packages/") t)
;; Comment/uncomment this line to enable MELPA Stable if desired.  See `package-archive-priorities`
;; and `package-pinned-packages`. Most users will not need or want to do this.
;;(add-to-list 'package-archives '("melpa-stable" . "https://stable.melpa.org/packages/") t)
(package-initialize)

(blink-cursor-mode -1)

(pdf-tools-install) ;;(pdf-loader-install) ; On demand loading, leads to faster startup time

;; annotation colours
(defun bms/pdf-annot-colour-gray ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "gray"))
 (highlight (color . "gray")) (squiggly (color . "gray"))
 (strike-out (color . "gray")) (underline (color . "gray"))))
  (message "%s" (propertize "Annotation colour set to gray." 'face '(:foreground "gray"))))
(defun bms/pdf-annot-colour-yellow ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "yellow"))
 (highlight (color . "yellow")) (squiggly (color . "yellow"))
 (strike-out (color . "yellow")) (underline (color . "yellow"))))
  (message "%s" (propertize "Annotation colour set to yellow." 'face '(:foreground "yellow"))))
(defun bms/pdf-annot-colour-pink ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "pink"))
 (highlight (color . "pink")) (squiggly (color . "pink"))
 (strike-out (color . "pink")) (underline (color . "pink"))))
  (message "%s" (propertize "Annotation colour set to pink." 'face '(:foreground "pink"))))
(defun bms/pdf-annot-colour-cyan ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "cyan"))
 (highlight (color . "cyan")) (squiggly (color . "cyan"))
 (strike-out (color . "cyan")) (underline (color . "cyan"))))
  (message "%s" (propertize "Annotation colour set to cyan." 'face '(:foreground "cyan"))))
(defun bms/pdf-annot-colour-blue ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "blue"))
 (highlight (color . "blue")) (squiggly (color . "blue"))
 (strike-out (color . "blue")) (underline (color . "blue"))))
  (message "%s" (propertize "Annotation colour set to blue." 'face '(:foreground "blue"))))
(defun bms/pdf-annot-colour-orange ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "orange"))
 (highlight (color . "orange")) (squiggly (color . "orange"))
 (strike-out (color . "orange")) (underline (color . "orange"))))
  (message "%s" (propertize "Annotation colour set to orange." 'face '(:foreground "orange"))))
(defun bms/pdf-annot-colour-gold ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "gold"))
 (highlight (color . "gold")) (squiggly (color . "gold"))
 (strike-out (color . "gold")) (underline (color . "gold"))))
  (message "%s" (propertize "Annotation colour set to gold." 'face '(:foreground "gold"))))
(defun bms/pdf-annot-colour-green ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "green"))
 (highlight (color . "green")) (squiggly (color . "green"))
 (strike-out (color . "green")) (underline (color . "green"))))
  (message "%s" (propertize "Annotation colour set to green." 'face '(:foreground "green"))))
(defun bms/pdf-annot-colour-red ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "red"))
 (highlight (color . "red")) (squiggly (color . "red"))
 (strike-out (color . "red")) (underline (color . "red"))))
  (message "%s" (propertize "Annotation colour set to red." 'face '(:foreground "red"))))
(defun bms/pdf-annot-colour-purple ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "purple"))
 (highlight (color . "purple")) (squiggly (color . "purple"))
 (strike-out (color . "purple")) (underline (color . "purple"))))
  (message "%s" (propertize "Annotation colour set to purple." 'face '(:foreground "purple"))))
(defun bms/pdf-annot-colour-silver ()
  (interactive)
  (setq pdf-annot-default-annotation-properties
        '((t (label . "Alessandro")) (text (icon . "Note") (color . "silver"))
 (highlight (color . "silver")) (squiggly (color . "silver"))
 (strike-out (color . "silver")) (underline (color . "silver"))))
  (message "%s" (propertize "Annotation colour set to silver." 'face '(:foreground "silver"))))

(defun bms/pdf-selection-style-glyph ()
  (interactive)
  (setq pdf-view-selection-style 'glyph)
  (message "%s" (propertize "Selection style set to glyph." 'face '(:foreground "gray"))))

(defun bms/pdf-selection-style-word ()
  (interactive)
  (setq pdf-view-selection-style 'word)
  (message "%s" (propertize "Selection style set to word." 'face '(:foreground "gray"))))

;; rebind keys for pdf-tools
(defun bms/pdf-tools-mode-config ()
  "Set pdf-tools keybindings."
  (local-set-key (kbd "a") #'bms/pdf-annot-colour-gray)
  (local-set-key (kbd "e") #'bms/pdf-annot-colour-yellow)
  (local-set-key (kbd "k") #'bms/pdf-annot-colour-pink)
  (local-set-key (kbd "y") #'bms/pdf-annot-colour-cyan)
  (local-set-key (kbd "b") #'bms/pdf-annot-colour-blue)
  (local-set-key (kbd "o") #'bms/pdf-annot-colour-orange)
  (local-set-key (kbd "g") #'bms/pdf-annot-colour-gold)
  (local-set-key (kbd "n") #'bms/pdf-annot-colour-green)
  (local-set-key (kbd "d") #'bms/pdf-annot-colour-red)
  (local-set-key (kbd "p") #'bms/pdf-annot-colour-purple)
  (local-set-key (kbd "s") #'bms/pdf-annot-colour-silver)
  (local-set-key (kbd ",") #'bms/pdf-selection-style-glyph)
  (local-set-key (kbd ".") #'bms/pdf-selection-style-word))



;; add to pdf-view-mode-hook
(add-hook 'pdf-view-mode-hook #'bms/pdf-tools-mode-config)

(add-hook 'pdf-outline-minor-mode-hook (lambda () (define-key pdf-outline-minor-mode-map (kbd "o") nil)))