Edit an open svg file in a separate buffer and update the view after the save

temp-edit-svg.el

;;; temp-edit-svg.el --- Edit svg in a temp buffer   -*- lexical-binding: t; -*-

;; Copyright (C) 2025  Arthur Miller

;; Author: Arthur Miller <[email protected]>
;; Keywords: 

;; 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:

;; 

;;; Code:

(defvar-local temp-edit-svg--real-buffer-file-name nil)
(defvar-local temp-edit-svg--working-buffer nil)

(defun save-temp-svg-buffer ()
  (interactive)
  (write-region (point-min) (point-max)
                temp-edit-svg--real-buffer-file-name)
  (when (buffer-live-p temp-edit-svg--working-buffer)
    (with-current-buffer temp-edit-svg--working-buffer
      (revert-buffer t t t))))

(defvar-keymap temp-edit-svg-mode-map
  "C-x C-s" #'save-temp-svg-buffer)

(define-minor-mode temp-edit-svg-mode
  "Save content of temp-edit-svg buffer.")

;;;###autoload
(defun temp-edit-svg ()
  "Edit SVG file in temp buffer"
  (interactive)
  (let ((svg buffer-file-name)
        (buf (current-buffer)))
    (unless (or (null svg) (string-suffix-p "svg" (file-name-extension svg)))
      (error "Current buffer is not displaying a SVG file."))
    (with-current-buffer (get-buffer-create
                          (generate-new-buffer-name (concat svg "-edit")))
      (nxml-mode)
      (temp-edit-svg-mode +1)
      (setf temp-edit-svg--real-buffer-file-name svg
            temp-edit-svg--working-buffer buf)
      (insert-file-contents-literally svg)
      (switch-to-buffer-other-window (current-buffer)))))

(provide 'temp-edit-svg)
;;; temp-edit-svg.el ends here