[elpa] externals/doc-view-follow dbb037d285 02/43: Add files via upload

[ELPA Syncer]

branch: externals/doc-view-follow
commit dbb037d2851e6f4cee03c7c664da903ce91e3aa8
Author: Paul Nelson <63298781+ultronozm@users.noreply.github.com>
Commit: GitHub <noreply@github.com>

    Add files via upload
---
 doc-dual-view.el | 139 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 139 insertions(+)

diff --git a/doc-dual-view.el b/doc-dual-view.el
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+;;; doc-dual-view.el --- Sync two windows showing the same document  -*- 
lexical-binding: t; -*-
+
+;; Copyright (C) 2024  Paul D. Nelson
+
+;; Author: Paul D. Nelson <nelson.paul.david@gmail.com>
+;; Keywords: convenience
+
+;; 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
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; This program is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;; This package provides a minor mode, `doc-dual-view-mode', that
+;; synchronizes page navigation between two windows displaying the
+;; same document, making it so that when you navigate to a page in one
+;; window, the other window will navigate to a neighboring page, so
+;; that the second window is always one page ahead of the first.
+
+;; Supports `doc-view-mode' and `pdf-view-mode'.  You can customize
+;; the `doc-dual-view-modes' variable to add support for additional
+;; document viewing modes or modify the behavior for existing modes.
+
+;;; Code:
+
+(require 'timer)
+
+(defgroup doc-dual-view nil
+  "Synchronize pages between two windows displaying the same document."
+  :group 'convenience)
+
+(defcustom doc-dual-view-modes
+  '((pdf-view-mode
+     (pdf-view-goto-page
+      pdf-view-next-page-command
+      pdf-view-previous-page-command)
+     (lambda () (pdf-view-current-page))
+     (lambda () (pdf-cache-number-of-pages))
+     pdf-view-redisplay)
+    (doc-view-mode
+     (doc-view-goto-page
+      doc-view-next-page
+      doc-view-previous-page)
+     (lambda () (doc-view-current-page))
+     (lambda () (doc-view-last-page-number))
+     doc-view-goto-page))
+  "Alist for supported modes.
+Given by (major-mode (goto-funcs) current-page-func max-page-func
+redisplay-func)."
+  :type '(repeat (list (symbol :tag "Major Mode")
+                       (repeat :tag "Goto Page Functions" symbol)
+                       (function :tag "Current Page Function")
+                       (function :tag "Max Page Function")
+                       (function :tag "Redisplay Function")))
+  :group 'doc-dual-view)
+
+(defvar-local doc-dual-view--redisplay-timer nil
+  "Timer for delayed redisplay.")
+
+(defun doc-dual-view--order-windows (windows)
+  "Order WINDOWS based on their position, leftmost (or topmost if equal) 
first."
+  (sort windows (lambda (a b)
+                  (let ((edges-a (window-edges a))
+                        (edges-b (window-edges b)))
+                    (or (< (car edges-a) (car edges-b))
+                        (and (= (car edges-a) (car edges-b))
+                             (< (cadr edges-a) (cadr edges-b))))))))
+
+(defun doc-dual-view--sync-pages (&rest _args)
+  "Sync pages between two windows showing the same document."
+  (let* ((mode-funcs (assoc major-mode doc-dual-view-modes))
+         (goto-funcs (nth 1 mode-funcs))
+         (current-page-func (nth 2 mode-funcs))
+         (max-page-func (nth 3 mode-funcs))
+         (redisplay-func (nth 4 mode-funcs)))
+    (when mode-funcs
+      (let ((windows (doc-dual-view--order-windows
+                      (get-buffer-window-list nil nil nil))))
+        (when (= (length windows) 2)
+          (let* ((first-window (car windows))
+                 (second-window (cadr windows))
+                 (current-page (funcall current-page-func))
+                 (max-page (funcall max-page-func))
+                 (target-page (if (eq (selected-window) first-window)
+                                  (min (1+ current-page) max-page)
+                                (max (1- current-page) 1))))
+            (with-selected-window (if (eq (selected-window) first-window)
+                                      second-window
+                                    first-window)
+              (let ((other-current-page (funcall current-page-func)))
+                (when (not (= other-current-page target-page))
+                  ;; Temporarily remove advice to prevent recursion
+                  (dolist (func goto-funcs)
+                    (advice-remove func #'doc-dual-view--sync-pages))
+                  (unwind-protect
+                      (progn
+                        (funcall (car goto-funcs) target-page)
+                        ;; Use timer for redisplay
+                        (when doc-dual-view--redisplay-timer
+                          (cancel-timer doc-dual-view--redisplay-timer))
+                        (setq doc-dual-view--redisplay-timer
+                              (run-with-idle-timer
+                               0.001 nil
+                               (lambda (win)
+                                 (when (window-live-p win)
+                                   (with-selected-window win
+                                     (funcall redisplay-func))))
+                               (selected-window))))
+                    ;; Re-add advice after execution
+                    (dolist (func goto-funcs)
+                      (advice-add
+                       func :after #'doc-dual-view--sync-pages))))))))))))
+
+;;;###autoload
+(define-minor-mode doc-dual-view-mode
+  "Minor mode to sync pages between two windows showing the same document."
+  :global nil
+  (dolist (mode-funcs doc-dual-view-modes)
+    (let ((goto-funcs (cadr mode-funcs)))
+      (dolist (goto-func goto-funcs)
+        (if doc-dual-view-mode
+            (advice-add goto-func :after #'doc-dual-view--sync-pages)
+          (advice-remove goto-func #'doc-dual-view--sync-pages)))))
+  (when (not doc-dual-view-mode)
+    (when doc-dual-view--redisplay-timer
+      (cancel-timer doc-dual-view--redisplay-timer)
+      (setq doc-dual-view--redisplay-timer nil))))
+
+(provide 'doc-dual-view)
+;;; doc-dual-view.el ends here