From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Ruijie Yu via Users list for the GNU Emacs text editor Newsgroups: gmane.emacs.help Subject: Re: How to temporarily show an image in an Emacs buffer? Date: Wed, 08 Mar 2023 14:19:10 +0800 Message-ID: References: <87bkl3etd1.fsf@mbork.pl> <87a60nerz2.fsf@mbork.pl> Reply-To: Ruijie Yu Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="34601"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: mu4e 1.8.14; emacs 30.0.50 Cc: help-gnu-emacs@gnu.org To: Marcin Borkowski Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Wed Mar 08 07:22:43 2023 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pZnCE-0008oa-Ne for geh-help-gnu-emacs@m.gmane-mx.org; Wed, 08 Mar 2023 07:22:42 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pZnBX-0005lW-31; Wed, 08 Mar 2023 01:21:59 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pZnBT-0005l5-3K for help-gnu-emacs@gnu.org; Wed, 08 Mar 2023 01:21:55 -0500 Original-Received: from netyu.xyz ([152.44.41.246] helo=mail.netyu.xyz) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pZnBR-0005FL-8k for help-gnu-emacs@gnu.org; Wed, 08 Mar 2023 01:21:54 -0500 Original-Received: from fw.net.yu.netyu.xyz ( [222.248.4.98]) by netyu.xyz (OpenSMTPD) with ESMTPSA id 47a85fec (TLSv1.3:TLS_AES_256_GCM_SHA384:256:NO); Wed, 8 Mar 2023 06:21:40 +0000 (UTC) In-reply-to: <87a60nerz2.fsf@mbork.pl> Received-SPF: pass client-ip=152.44.41.246; envelope-from=ruijie@netyu.xyz; helo=mail.netyu.xyz X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.help:142946 Archived-At: Marcin Borkowski writes: > On 2023-03-08, at 05:53, Marcin Borkowski wrote: > >> Alternatively, it _may_ change the buffer contents but in a way that is >> not recorded in `buffer-undo-list'. Is that possible? > > I did some experimenting, and this > > (defvar no-undo-marker (make-marker)) > (defun no-undo-insert () > "Test undo." > (save-excursion > (let ((buffer-undo-list)) > (set-marker no-undo-marker (point)) > (insert "this can't be undone\n")))) > > (defun no-undo-uninsert () > (save-excursion > (goto-char no-undo-marker) > (let ((buffer-undo-list)) > (when (looking-at-p "this can't be undone\n") > (delete-char 21))))) > > seems to do the trick, but depending on the order of typing and calling > these functions, the undo list becomes corrupted (I get "primitive-undo: > Changes to be undone are outside visible portion of buffer"). > > Any hints? Maybe you can make use of overlays [1]? That sounds like a great fit according to the description of your need. [1]: (info "(elisp) Managing Overlays") -- Best, RY