From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.help Subject: Re: Display of decomposed characters Date: Thu, 18 Mar 2021 17:01:36 +0200 Message-ID: <8335wsh5f3.fsf@gnu.org> References: <83v9csplwq.fsf@gnu.org> <83wnx5n1zw.fsf@gnu.org> <831rea3ymg.fsf@gnu.org> <0077B374-A65D-412D-B1A5-4ADDD50D41A7@gmail.com> <83pn0k825c.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="15706"; mail-complaints-to="usenet@ciao.gmane.io" To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane-mx.org@gnu.org Thu Mar 18 16:12:20 2021 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 1lMuJv-00040I-QE for geh-help-gnu-emacs@m.gmane-mx.org; Thu, 18 Mar 2021 16:12:19 +0100 Original-Received: from localhost ([::1]:45642 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMuJu-00072q-Qm for geh-help-gnu-emacs@m.gmane-mx.org; Thu, 18 Mar 2021 11:12:18 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:36816) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lMu9l-0005wN-20 for help-gnu-emacs@gnu.org; Thu, 18 Mar 2021 11:01:49 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:56743) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lMu9k-0006DC-P5 for help-gnu-emacs@gnu.org; Thu, 18 Mar 2021 11:01:48 -0400 Original-Received: from 84.94.185.95.cable.012.net.il ([84.94.185.95]:1069 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1lMu9e-0004DK-MF for help-gnu-emacs@gnu.org; Thu, 18 Mar 2021 11:01:47 -0400 In-Reply-To: (message from Philipp on Thu, 18 Mar 2021 15:16:42 +0100) X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.23 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" Xref: news.gmane.io gmane.emacs.help:128443 Archived-At: > From: Philipp > Date: Thu, 18 Mar 2021 15:16:42 +0100 > Cc: help-gnu-emacs@gnu.org > > > . we check whether the current character should compose with the > > following and/or preceding ones > > Is my understanding right that this is the step that comes too late, i.e. after font selection? It comes after the font selection, yes. And it cannot be any other way, because the shaping engine must have the font to return any meaningful results. The results of text shaping depend heavily on the font and its capabilities and features it supports. > Otherwise I'd assume that the answer is always "yes" if the current character is a combining character. Not only combining characters should be composed. In fact, in Emacs you can compose anything with anything else by tweaking a Lisp data structure. > >> What if Emacs ignored font lookup for combining characters and always picked the font of the previous base character? > > > > What would that produce if the font of the previous character didn't > > have a glyph for the accent? The accent will disappear, or maybe will > > be displayed as "tofu", right? Does that sound like a good strategy? > > Can't the shaping engine produce fake compositions in that case? What do you mean by "fake compositions"? what would they entail, and which glyphs would they use? > > That's bound to happen when a response comes more > > than a month after the original exchange. > > Yes, but unfortunately answering these questions takes some time, which I don't always have. I'll try to respond more timely in the future, but I can't really promise that. You don't have to promise, but you must understand that such long pauses almost guarantee that misunderstandings are more frequent.