From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Richard Stallman Newsgroups: gmane.emacs.devel Subject: Re: Can watermarking Unicode text using invisible differences sneak through Emacs, or can Emacs detect it? Date: Mon, 24 Jan 2022 23:16:29 -0500 Message-ID: References: <87sftk49ih.fsf@yahoo.com> <837dawt0h4.fsf@gnu.org> <838rv9plyf.fsf@gnu.org> <837dasntoj.fsf@gnu.org> <834k5tl4a9.fsf@gnu.org> Reply-To: rms@gnu.org Content-Type: text/plain; charset=Utf-8 Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="37312"; mail-complaints-to="usenet@ciao.gmane.io" Cc: psainty@orcon.net.nz, luangruo@yahoo.com, emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Jan 25 05:19:15 2022 Return-path: Envelope-to: ged-emacs-devel@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 1nCDIY-0009Yk-Hi for ged-emacs-devel@m.gmane-mx.org; Tue, 25 Jan 2022 05:19:14 +0100 Original-Received: from localhost ([::1]:56148 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nCDIX-0001Hm-GI for ged-emacs-devel@m.gmane-mx.org; Mon, 24 Jan 2022 23:19:13 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:52464) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nCDFx-0005zZ-KN for emacs-devel@gnu.org; Mon, 24 Jan 2022 23:16:33 -0500 Original-Received: from [2001:470:142:3::e] (port=54322 helo=fencepost.gnu.org) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nCDFw-0007gL-UO; Mon, 24 Jan 2022 23:16:32 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=Date:References:Subject:In-Reply-To:To:From: mime-version; bh=u15Df2QXcZhok3CsdrLxiNojdJPLh6SqiSvBxozaKA8=; b=kw6hhu2x1Ap5 iDjbgXFDVApHAM/HQhv+A9nLU2my9PE8rBxY0FXaSF7aeCp7TsyO4l8ASJ5IIYDiULjSuEy7akQMg MtEzELC7blUJvZtGLMEj/QP40CrkkG0yXhKRA0WTIa9xjkQ+1wIJg5clFMJHf1jHtcMKdPiD1ngu3 EFCMQ4NzVcwJJN9zs/LWy4d/ELCQvfna6AkeWcwMNbQXAm+vV5/iIbTvq9F+NQqQ7ocPRt1jHcP3O Q6v88KqSulXXYb4RD5BpAA1H6xtzTfHe2ew2eqfirE8aJcvnQT8tlB0FO1yxGA0k2sL2ouvsIkTSc bKeEkE/LZQvI+qaLJlZFjA==; Original-Received: from rms by fencepost.gnu.org with local (Exim 4.90_1) (envelope-from ) id 1nCDFt-0003Ir-7e; Mon, 24 Jan 2022 23:16:30 -0500 In-Reply-To: <834k5tl4a9.fsf@gnu.org> (message from Eli Zaretskii on Mon, 24 Jan 2022 14:14:06 +0200) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:285336 Archived-At: [[[ To any NSA and FBI agents reading my email: please consider ]]] [[[ whether defending the US Constitution against all enemies, ]]] [[[ foreign or domestic, requires you to follow Snowden's example. ]]] > How did that ligature get written to the screen? Was it present > literally in some text that Emacs displayed? It was in the buffer. That is why I was able to examine it with C-u C-x =. I suppose it was present in text that I visited in Emacs. > So let's please leave the literal fi > display alone, because it will take us far away from the original > issue. Thank you for clearly describing these two cases. I did not know that the ligature case people were discussing was limited to composition of characters -- that it was different from the case of displaying a ligature character actually in the buffer. What people said was sketchy and I had to try to fill in what was not said. > When several characters are supposed to > be composed on a text-mode display, Emacs simply writes them to the > terminal one after another, and expects the terminal to display them > as a ligature. The only difference between what Emacs does in this > case and what it does when no character composition is expected is > that in the former case Emacs expects the terminal to produce just one > glyph that takes just one column on display. In that case, I think I it would be good to be able to tell Emacs, when using a text-only terminal, not to try to compose ligatures. Not to expect that sequence to display as one column. Is that possible? -- Dr Richard Stallman (https://stallman.org) Chief GNUisance of the GNU Project (https://gnu.org) Founder, Free Software Foundation (https://fsf.org) Internet Hall-of-Famer (https://internethalloffame.org)