;;; beacon.el --- Highlight the cursor whenever it moves long distances -*- 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"))
+;; Package-Requires: ((seq "1.9"))
;; 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 or the buffer changes a light will shine on
+;; top of your cursor so you know where it is.
+;;
+;; That’s it.
+;;
+;;
+;; 1 Customizations
+;; ════════════════
+;;
+;; • To customize the appearance of the beacon, configure `beacon-size'
+;; and `beacon-color'.
+;;
+;; • To customize how long it lasts, configure `beacon-blink-duration'
+;; and `beacon-blink-delay'.
+;;
+;; • To customize /when/ it is used at all, configure
+;; `beacon-blink-when-window-scrolls',
+;; `beacon-blink-when-buffer-changes', and
+;; `beacon-blink-when-point-moves'.
;;; Code:
-(require 'cl-lib)
+(require 'seq)
(defgroup beacon nil
"Customization group for beacon."
"Add an after-string property to OVERLAY.
The property's value is a string of spaces with background
COLORS applied to each one."
- (overlay-put overlay 'beacon-colors colors)
- (overlay-put overlay 'after-string
- (mapconcat (lambda (c) (propertize " " 'face (list :background c)))
- colors
- "")))
+ (if (not colors)
+ (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."
- (let ((ov (make-overlay (point) (point))))
+ (let ((ov (make-overlay (point) (point)))
+ ;; The after-string must not be longer than the remaining columns from
+ ;; point to right window-end else it will be wrapped around (assuming
+ ;; truncate-lines is nil) introducing an ugly wrap-around for a
+ ;; fraction of a second.
+ (colors (seq-take colors (- (window-width) (current-column)))))
(beacon--ov-put-after-string ov colors)
(overlay-put ov 'beacon t)
(push ov beacon--ovs)))
(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 ()
"Turn off the beacon."
(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)))
- (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))))))))
+ (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 (progn (forward-char 1)
+ (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))))))))
(defun beacon-blink ()
"Blink the beacon at the position of the cursor."
(interactive)
(beacon--vanish)
- (beacon--shine)
- (setq beacon--timer
- (run-at-time beacon-blink-delay
- (/ beacon-blink-duration 1.0 beacon-size)
- #'beacon--dec)))
+ (unless (window-minibuffer-p)
+ (beacon--shine)
+ (setq beacon--timer
+ (run-at-time beacon-blink-delay
+ (/ beacon-blink-duration 1.0 beacon-size)
+ #'beacon--dec))))
\f
;;; Movement detection
+(defvar beacon--window-scrolled nil)
(defvar beacon--previous-place nil)
-(defvar beacon--previous-window-start nil)
(defvar beacon--previous-mark-head nil)
(defun beacon--movement-> (delta)
((not (equal (marker-buffer beacon--previous-place)
(current-buffer)))
(when beacon-blink-when-buffer-changes
- (unless (window-minibuffer-p)
- (beacon-blink))))
+ (beacon-blink)))
;; Blink for scrolling.
((and beacon-blink-when-window-scrolls
- (progn (redisplay)
- (not (equal beacon--previous-window-start (window-start)))))
- (beacon-blink))
+ beacon--window-scrolled
+ (equal beacon--window-scrolled (selected-window)))
+ (beacon-blink)
+ (setq beacon--window-scrolled nil))
;; Blink for movement
((beacon--movement-> beacon-blink-when-point-moves)
(beacon-blink))
(t (beacon--vanish)))
(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))))
+(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."
+ (if this-command
+ (setq beacon--window-scrolled win)
+ (beacon-blink)))
+
\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)
+ (progn
+ (add-hook 'window-scroll-functions #'beacon--window-scroll-function)
+ (add-hook 'post-command-hook #'beacon--post-command))
+ (remove-hook 'window-scroll-functions #'beacon--window-scroll-function)
(remove-hook 'post-command-hook #'beacon--post-command)))
(provide 'beacon)