From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: sbaugh@catern.com Newsgroups: gmane.emacs.devel Subject: Re: Horizontal centering in the display engine Date: Tue, 13 Apr 2021 16:49:59 -0400 Message-ID: <8735vtx62w.fsf@catern.com> References: <87fszuvy7p.fsf@catern.com> <83czuy112a.fsf@gnu.org> <877dl6vvax.fsf@catern.com> <83blai0y3i.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="22871"; mail-complaints-to="usenet@ciao.gmane.io" User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) To: emacs-devel@gnu.org Cancel-Lock: sha1:MEUCwTNVobdvF26SW+o+pAqJlOA= Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Tue Apr 13 22:51:50 2021 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 1lWQ0i-0005oq-Q1 for ged-emacs-devel@m.gmane-mx.org; Tue, 13 Apr 2021 22:51:48 +0200 Original-Received: from localhost ([::1]:37734 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lWQ0h-0005ig-Rq for ged-emacs-devel@m.gmane-mx.org; Tue, 13 Apr 2021 16:51:47 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:46728) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lWPz7-0004jS-Gk for emacs-devel@gnu.org; Tue, 13 Apr 2021 16:50:09 -0400 Original-Received: from ciao.gmane.io ([116.202.254.214]:33834) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lWPz5-0002b8-W9 for emacs-devel@gnu.org; Tue, 13 Apr 2021 16:50:09 -0400 Original-Received: from list by ciao.gmane.io with local (Exim 4.92) (envelope-from ) id 1lWPz4-00042X-6z for emacs-devel@gnu.org; Tue, 13 Apr 2021 22:50:06 +0200 X-Injected-Via-Gmane: http://gmane.org/ Received-SPF: pass client-ip=116.202.254.214; envelope-from=ged-emacs-devel@m.gmane-mx.org; helo=ciao.gmane.io X-Spam_score_int: -15 X-Spam_score: -1.6 X-Spam_bar: - X-Spam_report: (-1.6 / 5.0 requ) BAYES_00=-1.9, HEADER_FROM_DIFFERENT_DOMAINS=0.25, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 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:268013 Archived-At: Eli Zaretskii writes: >> From: sbaugh@catern.com >> To have centered text, I think I'd want to do something like >> >> :align-to (- center (0.5 . line-size)) >> >> [...] >> >> As far as I understand the documentation, there's no way to express >> something like line-size currently? Maybe that could be easily added? > > We have window-text-pixel-size, isn't that what you want? But that can't be used in a pixel specification, as far as I understand? And anyway, I don't think that's right - as the Elisp manual says, "window-text-pixel-size treats the text displayed in a window as a whole and does not care about the size of individual lines." > If that doesn't help, then I guess I'll ask you to describe the use > case in more detail. The behavior I want is what's described here: https://en.wikipedia.org/wiki/Typographic_alignment#Centered There's a picture on that page captioned "Centered text" which shows the desired behavior. > E.g., are you planning on centering each line separately, or > everything together, or something else? Each line separately. > IOW, how did you envision you'd put the display property on each line? The same display property would be applied to every line. > and how does this work when the user types text to add more lines, or > make a line longer than the window? etc. etc. When they add more lines, those new lines are also centered. If a line is longer than the window, it's truncated or wrapped depending on truncate-lines, word-wrap, etc., as usual.