-;;; beacon.el --- Highlight the cursor whenever it moves long distances -*- lexical-binding: t; -*-
+;;; beacon.el --- Highlight the cursor whenever the window scrolls -*- lexical-binding: t; -*-
-;; Copyright (C) 2015 Artur Malabarba
+;; Copyright (C) 2015 Free Software Foundation, Inc.
;; Author: Artur Malabarba <emacs@endlessparentheses.com>
;; URL: https://github.com/Malabarba/beacon
;; Keywords: convenience
-;; Version: 0.1
-;; Package-Requires: ((cl-lib "0.5"))
+;; Version: 1.3.1
+;; Package-Requires: ((seq "2.14"))
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;;; Commentary:
-;; This is a global minor-mode. Turn it on everywhere with
-;; (beacon-mode 1)
+;; This is a global minor-mode. Turn it on everywhere with:
+;; ┌────
+;; │ (beacon-mode 1)
+;; └────
+;;
+;; Whenever the window scrolls a light will shine on top of your cursor so
+;; you know where it is.
+;;
+;; That’s it.
+;;
+;; See the accompanying Readme.org for configuration details.
;;; Code:
-(require 'cl-lib)
+(require 'seq)
+(require 'faces)
+(unless (fboundp 'seq-mapn)
+ ;; This is for people who are on outdated Emacs snapshots. Will be
+ ;; deleted in a couple of weeks.
+ (defun seq-mapn (function sequence &rest sequences)
+ "Like `seq-map' but FUNCTION is mapped over all SEQUENCES.
+The arity of FUNCTION must match the number of SEQUENCES, and the
+mapping stops on the shortest sequence.
+Return a list of the results.
+
+\(fn FUNCTION SEQUENCES...)"
+ (let ((result nil)
+ (sequences (seq-map (lambda (s) (seq-into s 'list))
+ (cons sequence sequences))))
+ (while (not (memq nil sequences))
+ (push (apply function (seq-map #'car sequences)) result)
+ (setq sequences (seq-map #'cdr sequences)))
+ (nreverse result))))
(defgroup beacon nil
"Customization group for beacon."
(defvar beacon--timer nil)
-(defcustom beacon-push-mark nil
+(defcustom beacon-push-mark 35
"Should the mark be pushed before long movements?
If nil, `beacon' will not push the mark.
Otherwise this should be a number, and `beacon' will push the
mark whenever point moves more than that many lines."
:type '(choice integer (const nil)))
-(defcustom beacon-blink-when-point-moves nil
- "Should the beacon blink when moving a long distance?
-If nil, don't blink due to plain movement.
+(defcustom beacon-blink-when-point-moves-vertically nil
+ "Should the beacon blink when moving a long distance vertically?
+If nil, don't blink due to vertical movement.
If non-nil, this should be an integer, which is the minimum
movement distance (in lines) that triggers a beacon blink."
:type '(choice integer (const nil)))
+(defcustom beacon-blink-when-point-moves-horizontally nil
+ "Should the beacon blink when moving a long distance horizontally?
+If nil, don't blink due to horizontal movement.
+If non-nil, this should be an integer, which is the minimum
+movement distance (in columns) that triggers a beacon blink."
+ :type '(choice integer (const nil)))
+
(defcustom beacon-blink-when-buffer-changes t
"Should the beacon blink when changing buffer?"
:type 'boolean)
"Should the beacon blink when the window scrolls?"
:type 'boolean)
+(defcustom beacon-blink-when-window-changes t
+ "Should the beacon blink when the window changes?"
+ :type 'boolean)
+
+(defcustom beacon-blink-when-focused nil
+ "Should the beacon blink when Emacs gains focus?
+Note that, due to a limitation of `focus-in-hook', this might
+trigger false positives on some systems."
+ :type 'boolean
+ :package-version '(beacon . "0.2"))
+
(defcustom beacon-blink-duration 0.3
"Time, in seconds, that the blink should last."
:type 'number)
"Size of the beacon in characters."
:type 'number)
-(defcustom beacon-brightness 0.4
- "Brightness as a float between 0 and 1."
- :type 'number)
+(defcustom beacon-color 0.5
+ "Color of the beacon.
+This can be a string or a number.
+
+If it is a number, the color is taken to be white or
+black (depending on the current theme's background) and this
+number is a float between 0 and 1 specifing the brightness.
+
+If it is a string, it is a color name or specification,
+e.g. \"#666600\"."
+ :type '(choice number color))
+
+(defface beacon-fallback-background
+ '((((class color) (background light)) (:background "black"))
+ (((class color) (background dark)) (:background "white")))
+ "Fallback beacon background color.
+Used in cases where the color can't be determined by Emacs.
+Only the background of this face is used.")
+
+(defvar beacon-dont-blink-predicates nil
+ "A list of predicates that prevent the beacon blink.
+These predicate functions are called in order, with no
+arguments, before blinking the beacon. If any returns
+non-nil, the beacon will not blink.
+
+For instance, if you want to disable beacon on buffers where
+`hl-line-mode' is on, you can do:
+
+ (add-hook \\='beacon-dont-blink-predicates
+ (lambda () (bound-and-true-p hl-line-mode)))")
+
+(add-hook 'beacon-dont-blink-predicates #'window-minibuffer-p)
+
+(defcustom beacon-dont-blink-major-modes '(t magit-status-mode magit-popup-mode
+ inf-ruby-mode
+ gnus-summary-mode gnus-group-mode)
+ "A list of major-modes where the beacon won't blink.
+Whenever the current buffer satisfies `derived-mode-p' for
+one of the major-modes on this list, the beacon will not
+blink."
+ :type '(repeat symbol))
+
+(defcustom beacon-dont-blink-commands '(next-line previous-line
+ forward-line)
+ "A list of commands that should not make the beacon blink.
+Use this for commands that scroll the window in very
+predictable ways, when the blink would be more distracting
+than helpful.."
+ :type '(repeat symbol))
+
+(defcustom beacon-before-blink-hook nil
+ "Hook run immediately before blinking the beacon."
+ :type 'hook)
+
+\f
+;;; Internal variables
+(defvar beacon--window-scrolled nil)
+(defvar beacon--previous-place nil)
+(defvar beacon--previous-mark-head nil)
+(defvar beacon--previous-window nil)
+(defvar beacon--previous-window-start 0)
+
+(defun beacon--record-vars ()
+ (unless (window-minibuffer-p)
+ (setq beacon--previous-mark-head (car mark-ring))
+ (setq beacon--previous-place (point-marker))
+ (setq beacon--previous-window (selected-window))
+ (setq beacon--previous-window-start (window-start))))
\f
;;; Overlays
(defvar beacon--ovs nil)
-(defun beacon--colored-overlay (color)
+(defconst beacon-overlay-priority (/ most-positive-fixnum 2)
+ "Priotiy used on all of our overlays.")
+
+(defun beacon--make-overlay (length &rest properties)
"Put an overlay at point with background COLOR."
- (let ((ov (make-overlay (point) (1+ (point)))))
- (overlay-put ov 'face (list :background color))
+ (let ((ov (make-overlay (point) (+ length (point)))))
(overlay-put ov 'beacon t)
- (push ov beacon--ovs)))
+ ;; Our overlay is very temporary, so we take the liberty of giving
+ ;; it a high priority.
+ (overlay-put ov 'priority beacon-overlay-priority)
+ (overlay-put ov 'window (selected-window))
+ (while properties
+ (overlay-put ov (pop properties) (pop properties)))
+ (push ov beacon--ovs)
+ ov))
+
+(defun beacon--colored-overlay (color)
+ "Put an overlay at point with background COLOR."
+ (beacon--make-overlay 1 'face (list :background color)))
+
+(defun beacon--ov-put-after-string (overlay colors)
+ "Add an after-string property to OVERLAY.
+The property's value is a string of spaces with background
+COLORS applied to each one.
+If COLORS is nil, OVERLAY is deleted!"
+ (if (not colors)
+ (when (overlayp overlay)
+ (delete-overlay overlay))
+ (overlay-put overlay 'beacon-colors colors)
+ (overlay-put overlay 'after-string
+ (propertize
+ (mapconcat (lambda (c) (propertize " " 'face (list :background c)))
+ colors
+ "")
+ 'cursor 1000))))
+
+(defun beacon--after-string-overlay (colors)
+ "Put an overlay at point with an after-string property.
+The property's value is a string of spaces with background
+COLORS applied to each one."
+ ;; The after-string must not be longer than the remaining columns
+ ;; from point to right window-end else it will be wrapped around.
+ (let ((colors (seq-take colors (- (window-width) (current-column)))))
+ (beacon--ov-put-after-string (beacon--make-overlay 0) colors)))
(defun beacon--ov-at-point ()
- (car (cl-member-if (lambda (o) (overlay-get o 'beacon))
- (overlays-at (point)))))
+ (car (or (seq-filter (lambda (o) (overlay-get o 'beacon))
+ (overlays-in (point) (point)))
+ (seq-filter (lambda (o) (overlay-get o 'beacon))
+ (overlays-at (point))))))
-(defun beacon--vanish ()
+(defun beacon--vanish (&rest _)
"Turn off the beacon."
- (when (timerp beacon--timer)
- (cancel-timer beacon--timer))
- (mapc #'delete-overlay beacon--ovs)
- (setq beacon--ovs nil))
+ (unless (string-match "\\` \\*\\(temp-buffer\\|Echo Area.*\\)\\*"
+ (buffer-name))
+ (when (timerp beacon--timer)
+ (cancel-timer beacon--timer))
+ (mapc #'delete-overlay beacon--ovs)
+ (setq beacon--ovs nil)))
\f
;;; Colors
(defun beacon--color-range ()
"Return a list of background colors for the beacon."
- (let ((bg (color-values (face-attribute 'default :background))))
- (apply #'cl-mapcar (lambda (r g b) (format "#%04x%04x%04x" r g b))
- (if (< (color-distance "black" bg)
- (color-distance "white" bg))
- (mapcar (lambda (n) (butlast (beacon--int-range (* beacon-brightness 65535) n))) bg)
- (mapcar (lambda (n) (cdr (beacon--int-range (* (- 1 beacon-brightness) 65535) n))) bg)))))
+ (let* ((default-bg (or (save-excursion
+ (unless (eobp)
+ (forward-line 1)
+ (unless (or (bobp) (not (bolp)))
+ (forward-char -1)))
+ (background-color-at-point))
+ (face-background 'default)))
+ (bg (color-values (if (or (not (stringp default-bg))
+ (string-match "\\`unspecified-" default-bg))
+ (face-attribute 'beacon-fallback-background :background)
+ default-bg)))
+ (fg (cond
+ ((stringp beacon-color) (color-values beacon-color))
+ ((and (stringp bg)
+ (< (color-distance "black" bg)
+ (color-distance "white" bg)))
+ (make-list 3 (* beacon-color 65535)))
+ (t (make-list 3 (* (- 1 beacon-color) 65535))))))
+ (apply #'seq-mapn (lambda (r g b) (format "#%04x%04x%04x" r g b))
+ (mapcar (lambda (n) (butlast (beacon--int-range (elt fg n) (elt bg n))))
+ [0 1 2]))))
\f
;;; Blinking
(while colors
(if (looking-at "$")
(progn
- ;; (beacon--after-string)
+ (beacon--after-string-overlay colors)
(setq colors nil))
(beacon--colored-overlay (pop colors))
(forward-char 1))))))
(defun beacon--dec ()
"Decrease the beacon brightness by one."
- (let ((o (beacon--ov-at-point)))
- (if (not o)
- (beacon--vanish)
- (delete-overlay o)
- (save-excursion
- (while (progn (forward-char 1)
- (setq o (beacon--ov-at-point)))
- (move-overlay o (1- (point)) (point)))))))
+ (pcase (beacon--ov-at-point)
+ (`nil (beacon--vanish))
+ ((and o (let c (overlay-get o 'beacon-colors)) (guard c))
+ (beacon--ov-put-after-string o (cdr c)))
+ (o
+ (delete-overlay o)
+ (save-excursion
+ (while (and (condition-case nil
+ (progn (forward-char 1) t)
+ (end-of-buffer nil))
+ (setq o (beacon--ov-at-point)))
+ (let ((colors (overlay-get o 'beacon-colors)))
+ (if (not colors)
+ (move-overlay o (1- (point)) (point))
+ (forward-char -1)
+ (beacon--colored-overlay (pop colors))
+ (beacon--ov-put-after-string o colors)
+ (forward-char 1))))))))
+;;;###autoload
(defun beacon-blink ()
- "Blink the beacon at the position of the cursor."
+ "Blink the beacon at the position of the cursor.
+Unlike `beacon-blink-automated', the beacon will blink
+unconditionally (even if `beacon-mode' is disabled), and this can
+be invoked as a user command or called from lisp code."
(interactive)
(beacon--vanish)
+ (run-hooks 'beacon-before-blink-hook)
(beacon--shine)
(setq beacon--timer
(run-at-time beacon-blink-delay
(/ beacon-blink-duration 1.0 beacon-size)
#'beacon--dec)))
+(defun beacon-blink-automated ()
+ "If appropriate, blink the beacon at the position of the cursor.
+Unlike `beacon-blink', the blinking is conditioned on a series of
+variables: `beacon-mode', `beacon-dont-blink-commands',
+`beacon-dont-blink-major-modes', and
+`beacon-dont-blink-predicates'."
+ ;; Record vars here in case something is blinking outside the
+ ;; command loop.
+ (beacon--record-vars)
+ (unless (or (not beacon-mode)
+ (run-hook-with-args-until-success 'beacon-dont-blink-predicates)
+ (seq-find #'derived-mode-p beacon-dont-blink-major-modes)
+ (memq (or this-command last-command) beacon-dont-blink-commands))
+ (beacon-blink)))
+
\f
;;; Movement detection
-(defvar beacon--previous-place nil)
-(defvar beacon--previous-window-start nil)
-(defvar beacon--previous-mark-head nil)
-
-(defun beacon--movement-> (delta)
- "Return non-nil if latest point movement is > DELTA.
-If DELTA is nil, return nil."
- (and delta
+(defun beacon--movement-> (delta-y &optional delta-x)
+ "Return non-nil if latest vertical movement is > DELTA-Y.
+If DELTA-Y is nil, return nil.
+The same is true for DELTA-X and horizonta movement."
+ (and delta-y
+ (markerp beacon--previous-place)
(equal (marker-buffer beacon--previous-place)
(current-buffer))
+ ;; Quick check that prevents running the code below in very
+ ;; short movements (like typing).
(> (abs (- (point) beacon--previous-place))
- delta)
- (> (count-screen-lines (min (point) beacon--previous-place)
- (max (point) beacon--previous-place))
- delta)))
+ delta-y)
+ ;; Col movement.
+ (or (and delta-x
+ (> (abs (- (current-column)
+ (save-excursion
+ (goto-char beacon--previous-place)
+ (current-column))))
+ delta-x))
+ ;; Check if the movement was >= DELTA lines by moving DELTA
+ ;; lines. `count-screen-lines' is too slow if the movement had
+ ;; thousands of lines.
+ (save-excursion
+ (let ((p (point)))
+ (goto-char (min beacon--previous-place p))
+ (vertical-motion delta-y)
+ (> (max p beacon--previous-place)
+ (line-beginning-position)))))))
(defun beacon--maybe-push-mark ()
"Push mark if it seems to be safe."
(let ((head (car mark-ring)))
(when (and (eq beacon--previous-mark-head head)
(not (equal head beacon--previous-place)))
- (push-mark beacon--previous-place)))))
+ (push-mark beacon--previous-place 'silent)))))
(defun beacon--post-command ()
"Blink if point moved very far."
(cond
- ((not (markerp beacon--previous-place))
- (beacon--vanish))
- ;; Blink because we changed buffer.
- ((not (equal (marker-buffer beacon--previous-place)
- (current-buffer)))
- (when beacon-blink-when-buffer-changes
- (unless (window-minibuffer-p)
- (beacon-blink))))
+ ;; Sanity check.
+ ((not (markerp beacon--previous-place)))
+ ;; Blink for switching buffers.
+ ((and beacon-blink-when-buffer-changes
+ (not (eq (marker-buffer beacon--previous-place)
+ (current-buffer))))
+ (beacon-blink-automated))
+ ;; Blink for switching windows.
+ ((and beacon-blink-when-window-changes
+ (not (eq beacon--previous-window (selected-window))))
+ (beacon-blink-automated))
;; Blink for scrolling.
- ((and beacon-blink-when-window-scrolls
- (progn (redisplay)
- (not (equal beacon--previous-window-start (window-start)))))
- (beacon-blink))
+ ((and beacon--window-scrolled
+ (equal beacon--window-scrolled (selected-window)))
+ (beacon-blink-automated))
;; Blink for movement
- ((beacon--movement-> beacon-blink-when-point-moves)
- (beacon-blink))
- ;; Even if we don't blink, vanish any previous beacon.
- (t (beacon--vanish)))
+ ((beacon--movement-> beacon-blink-when-point-moves-vertically
+ beacon-blink-when-point-moves-horizontally)
+ (beacon-blink-automated)))
(beacon--maybe-push-mark)
- (unless (window-minibuffer-p)
- (setq beacon--previous-window-start (window-start))
- (setq beacon--previous-mark-head (car mark-ring))
- (setq beacon--previous-place (point-marker))))
+ (setq beacon--window-scrolled nil))
+
+(defun beacon--window-scroll-function (win start-pos)
+ "Blink the beacon or record that window has been scrolled.
+If invoked during the command loop, record the current window so
+that it may be blinked on post-command. This is because the
+scrolled window might not be active, but we only know that at
+`post-command-hook'.
+
+If invoked outside the command loop, `post-command-hook' would be
+unreliable, so just blink immediately."
+ (unless (or (and (equal beacon--previous-window-start start-pos)
+ (equal beacon--previous-window win))
+ (not beacon-blink-when-window-scrolls))
+ (if this-command
+ (setq beacon--window-scrolled win)
+ (setq beacon--window-scrolled nil)
+ (beacon-blink-automated))))
+
+(defun beacon--blink-on-focus ()
+ "Blink if `beacon-blink-when-focused' is non-nil"
+ (when beacon-blink-when-focused
+ (beacon-blink-automated)))
\f
;;; Minor-mode
-(defcustom beacon-lighter (cond
- ((char-displayable-p ?💡) "💡")
- ((char-displayable-p ?Λ) "Λ")
- (t "*"))
+(defcustom beacon-lighter
+ (cond
+ ;; ((char-displayable-p ?💡) " 💡")
+ ;; ((char-displayable-p ?Λ) " Λ")
+ (t " (*)"))
"Lighter string used on the mode-line."
:type 'string)
nil nil beacon-lighter nil
:global t
(if beacon-mode
- (add-hook 'post-command-hook #'beacon--post-command)
- (remove-hook 'post-command-hook #'beacon--post-command)))
+ (progn
+ (add-hook 'window-scroll-functions #'beacon--window-scroll-function)
+ (add-hook 'focus-in-hook #'beacon--blink-on-focus)
+ (add-hook 'post-command-hook #'beacon--post-command)
+ (add-hook 'before-change-functions #'beacon--vanish)
+ (add-hook 'pre-command-hook #'beacon--record-vars)
+ (add-hook 'pre-command-hook #'beacon--vanish))
+ (remove-hook 'focus-in-hook #'beacon--blink-on-focus)
+ (remove-hook 'window-scroll-functions #'beacon--window-scroll-function)
+ (remove-hook 'post-command-hook #'beacon--post-command)
+ (remove-hook 'before-change-functions #'beacon--vanish)
+ (remove-hook 'pre-command-hook #'beacon--record-vars)
+ (remove-hook 'pre-command-hook #'beacon--vanish)))
(provide 'beacon)
;;; beacon.el ends here
+
+;; Local Variables:
+;; indent-tabs-mode: nil
+;; End: