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: Verticality and future of display engine and lines (bis) [Was: Re: RTL lines] Date: Thu, 28 Oct 2021 09:53:21 +0300 Message-ID: <83wnlxtzby.fsf@gnu.org> References: <3519414.WYFCpekPd3@galex-713.eu> <3414507.SNmyYOu4Ja@galex-713.eu> <838ryeuwew.fsf@gnu.org> <7275793.Xk2IM2Q3GM@galex-713.eu> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="9524"; 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 Oct 28 08:54:07 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 1mfzId-0002Ee-IF for geh-help-gnu-emacs@m.gmane-mx.org; Thu, 28 Oct 2021 08:54:07 +0200 Original-Received: from localhost ([::1]:34886 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mfzIb-0006zn-IY for geh-help-gnu-emacs@m.gmane-mx.org; Thu, 28 Oct 2021 02:54:05 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:44020) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mfzHu-0006zR-Bm for help-gnu-emacs@gnu.org; Thu, 28 Oct 2021 02:53:22 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:38988) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mfzHu-0007D0-3X for help-gnu-emacs@gnu.org; Thu, 28 Oct 2021 02:53:22 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-version:References:Subject:In-Reply-To:To:From: Date; bh=tNAwSlMKZ6I55QHggIlv+p36dOj6v9Yqo8IOFcEU1rc=; b=gD0estP77w9R8PvrcVQ9 Z1HNNGgq94RavNl/PzU5yKcqswaXiKFfCgeO9YIscrGPrt+U9K39j+CWjgCkKMdWqCgeL6qYu5OzE oeeb3//1OTwSRfJQnqK43xsy/VAYF8d5HNfNwQKpO8SG202TS1k7Oe7JQeJ4Bj+Pfy8RVg9zq7uSe 8aUyiFwRgwBPNuCanx5Kd6HCvalk4vDNQjL09gYaGtiKxmORw+hZAPQyd76T1t6EiFSLjd7WBDw01 5jgohglzaS4RdnCyY+KyHxQV21NHX31+C+8cMt2ScR8wRTp2nTOCfCEQ+i+HZkiL08cEI6XMD4xLK KQOF5nOSl5oT7Q==; Original-Received: from [87.69.77.57] (port=1303 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mfzHt-00085Z-KM for help-gnu-emacs@gnu.org; Thu, 28 Oct 2021 02:53:21 -0400 In-Reply-To: <7275793.Xk2IM2Q3GM@galex-713.eu> (message from Alexandre Garreau on Wed, 27 Oct 2021 21:54:11 +0200) 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:134249 Archived-At: > From: Alexandre Garreau > Date: Wed, 27 Oct 2021 21:54:11 +0200 > > > So you are not only talking about a revolution in the display engine, > > you are also talking about a revolution in scrolling commands. > > That’s less than half a dozen of commands and the change is trivial, it’s > just level of abstraction. I guess you are unaware, or perhaps forgot, that the display engine itself scrolls the window when it finds that necessary. > > I don't see any excess height of the lines, I think if you see that in > > Emacs, you have a faulty font or something. > > Did you really look at the screenshots? don’t you see all the blank > between the lines? I'm talking about what I see in my Emacs session where I read your email. If any Emacs session displays that as you describe, that's either a font configuration problem or some rendering bug that isn't present in my build of Emacs. > > Showing just one diacritic is TRT in this case. Anything else is a > > display bug. > > So how do you display languages which *need* several diacritics? Not every arbitrary combination of the diacritics on the same base character is valid. Lumping the same diacritic several times on the same base character certainly isn't. For valid combination of the diacritics, we will display them the way the font and the shaping engine (HarfBuzz) tell us to do. IOW, find a real-life case with several diacritics on the same character, and then let's talk. The example you provided makes no sense in real life, and the correct reaction of the Emacs display engine to that nonsensical example is to show just one diacritic. > > > Btw it would be nice if emacs supported such tweaking of > > > directionality > > > (although my friend wouldn’t benefit from it since he’s a user of vim, > > > but I’m pretty sure that would be a point in advertising emacs to > > > him). > > You can have this with special bidirectional formatting control > > characters, like LRO and RLO. Emacs supports them. > > Yes I know but I mean to have that systematically without having to > manually enter them at each script change (and avoiding to put them in a > possibly shared file with people with different opinions regarding > directionality) Using those formatting controls _is_ the systematic way of changing the text directionality. Emacs is not a playground for arbitrarily messing with the text layout, it follows relevant standards of layout. And in those standards, the _only_ way of controlling the text directionality is by using directionality controls and overrides. You could, of course, go overboard and modify the basic properties of the characters, which Emacs holds in char-tables. But that is not recommended, and I'm not even sure I understand why would you like to do something like that.