482 lines
17 KiB
EmacsLisp
482 lines
17 KiB
EmacsLisp
;;; beacon.el --- Highlight the cursor whenever the window scrolls -*- lexical-binding: t; -*-
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;; Copyright (C) 2015 Free Software Foundation, Inc.
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;; Author: Artur Malabarba <emacs@endlessparentheses.com>
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;; URL: https://github.com/Malabarba/beacon
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;; Package-Version: 20161004.756
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;; Keywords: convenience
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;; Version: 1.3.2
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;; Package-Requires: ((seq "2.14"))
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;; This program is free software; you can redistribute it and/or modify
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;; it under the terms of the GNU General Public License as published by
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;; the Free Software Foundation, either version 3 of the License, or
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;; (at your option) any later version.
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;; This program is distributed in the hope that it will be useful,
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;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;; GNU General Public License for more details.
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;; You should have received a copy of the GNU General Public License
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;; along with this program. If not, see <http://www.gnu.org/licenses/>.
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;;; Commentary:
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;; This is a global minor-mode. Turn it on everywhere with:
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;; ┌────
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;; │ (beacon-mode 1)
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;; └────
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;;
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;; Whenever the window scrolls a light will shine on top of your cursor so
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;; you know where it is.
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;;
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;; That’s it.
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;;
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;; See the accompanying Readme.org for configuration details.
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;;; Code:
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(require 'seq)
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(require 'faces)
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(unless (fboundp 'seq-mapn)
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;; This is for people who are on outdated Emacs snapshots. Will be
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;; deleted in a couple of weeks.
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(defun seq-mapn (function sequence &rest sequences)
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"Like `seq-map' but FUNCTION is mapped over all SEQUENCES.
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The arity of FUNCTION must match the number of SEQUENCES, and the
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mapping stops on the shortest sequence.
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Return a list of the results.
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\(fn FUNCTION SEQUENCES...)"
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(let ((result nil)
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(sequences (seq-map (lambda (s) (seq-into s 'list))
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(cons sequence sequences))))
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(while (not (memq nil sequences))
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(push (apply function (seq-map #'car sequences)) result)
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(setq sequences (seq-map #'cdr sequences)))
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(nreverse result))))
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(defgroup beacon nil
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"Customization group for beacon."
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:group 'emacs
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:prefix "beacon-")
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(defvar beacon--timer nil)
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(defcustom beacon-push-mark 35
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"Should the mark be pushed before long movements?
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If nil, `beacon' will not push the mark.
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Otherwise this should be a number, and `beacon' will push the
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mark whenever point moves more than that many lines."
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:type '(choice integer (const nil)))
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(defcustom beacon-blink-when-point-moves-vertically nil
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"Should the beacon blink when moving a long distance vertically?
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If nil, don't blink due to vertical movement.
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If non-nil, this should be an integer, which is the minimum
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movement distance (in lines) that triggers a beacon blink."
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:type '(choice integer (const nil)))
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(defcustom beacon-blink-when-point-moves-horizontally nil
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"Should the beacon blink when moving a long distance horizontally?
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If nil, don't blink due to horizontal movement.
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If non-nil, this should be an integer, which is the minimum
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movement distance (in columns) that triggers a beacon blink."
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:type '(choice integer (const nil)))
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(defcustom beacon-blink-when-buffer-changes t
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"Should the beacon blink when changing buffer?"
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:type 'boolean)
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(defcustom beacon-blink-when-window-scrolls t
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"Should the beacon blink when the window scrolls?"
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:type 'boolean)
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(defcustom beacon-blink-when-window-changes t
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"Should the beacon blink when the window changes?"
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:type 'boolean)
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(defcustom beacon-blink-when-focused nil
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"Should the beacon blink when Emacs gains focus?
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Note that, due to a limitation of `focus-in-hook', this might
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trigger false positives on some systems."
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:type 'boolean
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:package-version '(beacon . "0.2"))
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(defcustom beacon-blink-duration 0.3
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"Time, in seconds, that the blink should last."
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:type 'number)
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(defcustom beacon-blink-delay 0.3
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"Time, in seconds, before starting to fade the beacon."
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:type 'number)
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(defcustom beacon-size 40
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"Size of the beacon in characters."
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:type 'number)
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(defcustom beacon-color 0.5
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"Color of the beacon.
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This can be a string or a number.
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If it is a number, the color is taken to be white or
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black (depending on the current theme's background) and this
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number is a float between 0 and 1 specifing the brightness.
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If it is a string, it is a color name or specification,
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e.g. \"#666600\"."
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:type '(choice number color))
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(defface beacon-fallback-background
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'((((class color) (background light)) (:background "black"))
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(((class color) (background dark)) (:background "white")))
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"Fallback beacon background color.
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Used in cases where the color can't be determined by Emacs.
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Only the background of this face is used.")
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(defvar beacon-dont-blink-predicates nil
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"A list of predicates that prevent the beacon blink.
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These predicate functions are called in order, with no
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arguments, before blinking the beacon. If any returns
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non-nil, the beacon will not blink.
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For instance, if you want to disable beacon on buffers where
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`hl-line-mode' is on, you can do:
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(add-hook \\='beacon-dont-blink-predicates
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(lambda () (bound-and-true-p hl-line-mode)))")
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(defun beacon--compilation-mode-p ()
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"Non-nil if this is some form of compilation mode."
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(or (derived-mode-p 'compilation-mode)
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(bound-and-true-p compilation-minor-mode)))
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(add-hook 'beacon-dont-blink-predicates #'window-minibuffer-p)
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(add-hook 'beacon-dont-blink-predicates #'beacon--compilation-mode-p)
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(defcustom beacon-dont-blink-major-modes '(t magit-status-mode magit-popup-mode
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inf-ruby-mode
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gnus-summary-mode gnus-group-mode)
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"A list of major-modes where the beacon won't blink.
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Whenever the current buffer satisfies `derived-mode-p' for
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one of the major-modes on this list, the beacon will not
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blink."
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:type '(repeat symbol))
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(defcustom beacon-dont-blink-commands '(next-line previous-line
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forward-line)
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"A list of commands that should not make the beacon blink.
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Use this for commands that scroll the window in very
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predictable ways, when the blink would be more distracting
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than helpful.."
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:type '(repeat symbol))
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(defcustom beacon-before-blink-hook nil
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"Hook run immediately before blinking the beacon."
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:type 'hook)
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;;; Internal variables
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(defvar beacon--window-scrolled nil)
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(defvar beacon--previous-place nil)
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(defvar beacon--previous-mark-head nil)
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(defvar beacon--previous-window nil)
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(defvar beacon--previous-window-start 0)
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(defun beacon--record-vars ()
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(unless (window-minibuffer-p)
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(setq beacon--previous-mark-head (car mark-ring))
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(setq beacon--previous-place (point-marker))
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(setq beacon--previous-window (selected-window))
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(setq beacon--previous-window-start (window-start))))
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;;; Overlays
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(defvar beacon--ovs nil)
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(defconst beacon-overlay-priority (/ most-positive-fixnum 2)
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"Priotiy used on all of our overlays.")
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(defun beacon--make-overlay (length &rest properties)
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"Put an overlay at point with background COLOR."
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(let ((ov (make-overlay (point) (+ length (point)))))
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(overlay-put ov 'beacon t)
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;; Our overlay is very temporary, so we take the liberty of giving
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;; it a high priority.
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(overlay-put ov 'priority beacon-overlay-priority)
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(overlay-put ov 'window (selected-window))
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(while properties
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(overlay-put ov (pop properties) (pop properties)))
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(push ov beacon--ovs)
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ov))
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(defun beacon--colored-overlay (color)
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"Put an overlay at point with background COLOR."
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(beacon--make-overlay 1 'face (list :background color)))
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(defun beacon--ov-put-after-string (overlay colors)
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"Add an after-string property to OVERLAY.
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The property's value is a string of spaces with background
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COLORS applied to each one.
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If COLORS is nil, OVERLAY is deleted!"
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(if (not colors)
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(when (overlayp overlay)
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(delete-overlay overlay))
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(overlay-put overlay 'beacon-colors colors)
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(overlay-put overlay 'after-string
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(propertize
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(mapconcat (lambda (c) (propertize " " 'face (list :background c)))
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colors
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"")
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'cursor 1000))))
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(defun beacon--after-string-overlay (colors)
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"Put an overlay at point with an after-string property.
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The property's value is a string of spaces with background
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COLORS applied to each one."
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;; The after-string must not be longer than the remaining columns
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;; from point to right window-end else it will be wrapped around.
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(let ((colors (seq-take colors (- (window-width) (current-column)))))
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(beacon--ov-put-after-string (beacon--make-overlay 0) colors)))
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(defun beacon--ov-at-point ()
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(car (or (seq-filter (lambda (o) (overlay-get o 'beacon))
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(overlays-in (point) (point)))
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(seq-filter (lambda (o) (overlay-get o 'beacon))
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(overlays-at (point))))))
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(defun beacon--vanish (&rest _)
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"Turn off the beacon."
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(unless (string-match "\\` \\*\\(temp-buffer\\|Echo Area.*\\)\\*"
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(buffer-name))
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(when (timerp beacon--timer)
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(cancel-timer beacon--timer))
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(mapc #'delete-overlay beacon--ovs)
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(setq beacon--ovs nil)))
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;;; Colors
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(defun beacon--int-range (a b)
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"Return a list of integers between A inclusive and B exclusive.
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Only returns `beacon-size' elements."
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(let ((d (/ (- b a) beacon-size))
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(out (list a)))
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(dotimes (_ (1- beacon-size))
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(push (+ (car out) d) out))
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(nreverse out)))
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(defun beacon--color-range ()
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"Return a list of background colors for the beacon."
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(let* ((default-bg (or (save-excursion
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(unless (eobp)
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(forward-line 1)
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(unless (or (bobp) (not (bolp)))
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(forward-char -1)))
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(background-color-at-point))
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(face-background 'default)))
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(bg (color-values (if (or (not (stringp default-bg))
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(string-match "\\`unspecified-" default-bg))
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(face-attribute 'beacon-fallback-background :background)
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default-bg)))
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(fg (cond
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((stringp beacon-color) (color-values beacon-color))
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((and (stringp bg)
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(< (color-distance "black" bg)
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(color-distance "white" bg)))
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(make-list 3 (* beacon-color 65535)))
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(t (make-list 3 (* (- 1 beacon-color) 65535))))))
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(when bg
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(apply #'seq-mapn (lambda (r g b) (format "#%04x%04x%04x" r g b))
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(mapcar (lambda (n) (butlast (beacon--int-range (elt fg n) (elt bg n))))
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[0 1 2])))))
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;;; Blinking
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(defun beacon--shine ()
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"Shine a beacon at point."
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(let ((colors (beacon--color-range)))
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(save-excursion
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(while colors
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(if (looking-at "$")
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(progn
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(beacon--after-string-overlay colors)
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(setq colors nil))
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(beacon--colored-overlay (pop colors))
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(forward-char 1))))))
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(defun beacon--dec ()
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"Decrease the beacon brightness by one."
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(pcase (beacon--ov-at-point)
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(`nil (beacon--vanish))
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((and o (let c (overlay-get o 'beacon-colors)) (guard c))
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(beacon--ov-put-after-string o (cdr c)))
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(o
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(delete-overlay o)
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(save-excursion
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(while (and (condition-case nil
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(progn (forward-char 1) t)
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(end-of-buffer nil))
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(setq o (beacon--ov-at-point)))
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(let ((colors (overlay-get o 'beacon-colors)))
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(if (not colors)
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(move-overlay o (1- (point)) (point))
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(forward-char -1)
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(beacon--colored-overlay (pop colors))
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(beacon--ov-put-after-string o colors)
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(forward-char 1))))))))
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;;;###autoload
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(defun beacon-blink ()
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"Blink the beacon at the position of the cursor.
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Unlike `beacon-blink-automated', the beacon will blink
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unconditionally (even if `beacon-mode' is disabled), and this can
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be invoked as a user command or called from lisp code."
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(interactive)
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(beacon--vanish)
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(run-hooks 'beacon-before-blink-hook)
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(beacon--shine)
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(setq beacon--timer
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(run-at-time beacon-blink-delay
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(/ beacon-blink-duration 1.0 beacon-size)
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#'beacon--dec)))
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(defun beacon-blink-automated ()
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"If appropriate, blink the beacon at the position of the cursor.
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Unlike `beacon-blink', the blinking is conditioned on a series of
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variables: `beacon-mode', `beacon-dont-blink-commands',
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`beacon-dont-blink-major-modes', and
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`beacon-dont-blink-predicates'."
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;; Record vars here in case something is blinking outside the
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;; command loop.
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(beacon--record-vars)
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(unless (or (not beacon-mode)
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(run-hook-with-args-until-success 'beacon-dont-blink-predicates)
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(seq-find #'derived-mode-p beacon-dont-blink-major-modes)
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(memq (or this-command last-command) beacon-dont-blink-commands))
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(beacon-blink)))
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;;; Movement detection
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(defun beacon--movement-> (delta-y &optional delta-x)
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"Return non-nil if latest vertical movement is > DELTA-Y.
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If DELTA-Y is nil, return nil.
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The same is true for DELTA-X and horizonta movement."
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(and delta-y
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(markerp beacon--previous-place)
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(equal (marker-buffer beacon--previous-place)
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(current-buffer))
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;; Quick check that prevents running the code below in very
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;; short movements (like typing).
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(> (abs (- (point) beacon--previous-place))
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delta-y)
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;; Col movement.
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(or (and delta-x
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(> (abs (- (current-column)
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(save-excursion
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(goto-char beacon--previous-place)
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(current-column))))
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delta-x))
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;; Check if the movement was >= DELTA lines by moving DELTA
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;; lines. `count-screen-lines' is too slow if the movement had
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;; thousands of lines.
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(save-excursion
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(let ((p (point)))
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(goto-char (min beacon--previous-place p))
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(vertical-motion delta-y)
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(> (max p beacon--previous-place)
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(line-beginning-position)))))))
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(defun beacon--maybe-push-mark ()
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"Push mark if it seems to be safe."
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(when (and (not mark-active)
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(beacon--movement-> beacon-push-mark))
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(let ((head (car mark-ring)))
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(when (and (eq beacon--previous-mark-head head)
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(not (equal head beacon--previous-place)))
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(push-mark beacon--previous-place 'silent)))))
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(defun beacon--post-command ()
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"Blink if point moved very far."
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(cond
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;; Sanity check.
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((not (markerp beacon--previous-place)))
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;; Blink for switching buffers.
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((and beacon-blink-when-buffer-changes
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(not (eq (marker-buffer beacon--previous-place)
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(current-buffer))))
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(beacon-blink-automated))
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;; Blink for switching windows.
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((and beacon-blink-when-window-changes
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(not (eq beacon--previous-window (selected-window))))
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(beacon-blink-automated))
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;; Blink for scrolling.
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((and beacon--window-scrolled
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(equal beacon--window-scrolled (selected-window)))
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(beacon-blink-automated))
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;; Blink for movement
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((beacon--movement-> beacon-blink-when-point-moves-vertically
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beacon-blink-when-point-moves-horizontally)
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(beacon-blink-automated)))
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(beacon--maybe-push-mark)
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(setq beacon--window-scrolled nil))
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(defun beacon--window-scroll-function (win start-pos)
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"Blink the beacon or record that window has been scrolled.
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If invoked during the command loop, record the current window so
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that it may be blinked on post-command. This is because the
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scrolled window might not be active, but we only know that at
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`post-command-hook'.
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If invoked outside the command loop, `post-command-hook' would be
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unreliable, so just blink immediately."
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(unless (or (and (equal beacon--previous-window-start start-pos)
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(equal beacon--previous-window win))
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(not beacon-blink-when-window-scrolls))
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(if this-command
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(setq beacon--window-scrolled win)
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(setq beacon--window-scrolled nil)
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(beacon-blink-automated))))
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(defun beacon--blink-on-focus ()
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"Blink if `beacon-blink-when-focused' is non-nil"
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(when beacon-blink-when-focused
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(beacon-blink-automated)))
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;;; Minor-mode
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(defcustom beacon-lighter
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(cond
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;; ((char-displayable-p ?💡) " 💡")
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;; ((char-displayable-p ?Λ) " Λ")
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(t " (*)"))
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"Lighter string used on the mode-line."
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:type 'string)
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;;;###autoload
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(define-minor-mode beacon-mode
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nil nil beacon-lighter nil
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:global t
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(if beacon-mode
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(progn
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(add-hook 'window-scroll-functions #'beacon--window-scroll-function)
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(add-hook 'focus-in-hook #'beacon--blink-on-focus)
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(add-hook 'post-command-hook #'beacon--post-command)
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(add-hook 'before-change-functions #'beacon--vanish)
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(add-hook 'pre-command-hook #'beacon--record-vars)
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(add-hook 'pre-command-hook #'beacon--vanish))
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(remove-hook 'focus-in-hook #'beacon--blink-on-focus)
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(remove-hook 'window-scroll-functions #'beacon--window-scroll-function)
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(remove-hook 'post-command-hook #'beacon--post-command)
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(remove-hook 'before-change-functions #'beacon--vanish)
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(remove-hook 'pre-command-hook #'beacon--record-vars)
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(remove-hook 'pre-command-hook #'beacon--vanish)))
|
||
|
||
(provide 'beacon)
|
||
;;; beacon.el ends here
|
||
|
||
;; Local Variables:
|
||
;; indent-tabs-mode: nil
|
||
;; End:
|