From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Marcin Borkowski Newsgroups: gmane.emacs.help Subject: Re: How to temporarily show an image in an Emacs buffer? Date: Wed, 08 Mar 2023 17:01:34 +0100 Message-ID: <875ybbdyg1.fsf@mbork.pl> References: <87bkl3etd1.fsf@mbork.pl> <87a60nerz2.fsf@mbork.pl> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="28036"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: mu4e 1.1.0; emacs 30.0.50 Cc: help-gnu-emacs@gnu.org To: Ruijie Yu Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Wed Mar 08 17:02:09 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 1pZwEy-000746-Qu for geh-help-gnu-emacs@m.gmane-mx.org; Wed, 08 Mar 2023 17:02:08 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pZwEm-0000KV-DC; Wed, 08 Mar 2023 11:01:56 -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 1pZwEa-0000Jq-Et for help-gnu-emacs@gnu.org; Wed, 08 Mar 2023 11:01:44 -0500 Original-Received: from mail.mojserwer.eu ([195.110.48.8]) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pZwEX-0003WF-Eu for help-gnu-emacs@gnu.org; Wed, 08 Mar 2023 11:01:44 -0500 Original-Received: from localhost (localhost [127.0.0.1]) by mail.mojserwer.eu (Postfix) with ESMTP id 0C0DE64A19E; Wed, 8 Mar 2023 17:01:39 +0100 (CET) X-Virus-Scanned: Debian amavisd-new at mail.mojserwer.eu Original-Received: from mail.mojserwer.eu ([127.0.0.1]) by localhost (mail.mojserwer.eu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 8IYwCEXYLeA2; Wed, 8 Mar 2023 17:01:35 +0100 (CET) Original-Received: from localhost (91-227-196-3.net4me.pl [91.227.196.3]) by mail.mojserwer.eu (Postfix) with ESMTPSA id 49ECA68BE02; Wed, 8 Mar 2023 17:01:35 +0100 (CET) In-reply-to: Received-SPF: pass client-ip=195.110.48.8; envelope-from=mbork@mbork.pl; helo=mail.mojserwer.eu X-Spam_score_int: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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:142949 Archived-At: On 2023-03-08, at 07:19, Ruijie Yu wrote: > 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") As I said in my reply to Eli, you were right. (I knew about overlays, but I didn't know that apparently you can use an overlay with a `before-string' property /and/ put another display property on the /string/ being the value of `before-string', which is kind of cool!) Thanks, -- Marcin Borkowski http://mbork.pl