From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Yuri D'Elia Newsgroups: gmane.emacs.help Subject: Re: otf ligature rendering support? Date: Sat, 03 Jan 2015 11:44:25 +0100 Message-ID: References: <83tx099ofu.fsf@gnu.org> <83ppax9ndy.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Trace: ger.gmane.org 1420281904 18813 80.91.229.3 (3 Jan 2015 10:45:04 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Sat, 3 Jan 2015 10:45:04 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Sat Jan 03 11:44:57 2015 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1Y7MCW-0002Qx-Gl for geh-help-gnu-emacs@m.gmane.org; Sat, 03 Jan 2015 11:44:56 +0100 Original-Received: from localhost ([::1]:53970 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y7MCV-0001vc-PS for geh-help-gnu-emacs@m.gmane.org; Sat, 03 Jan 2015 05:44:55 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:54963) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y7MCK-0001vW-Ay for help-gnu-emacs@gnu.org; Sat, 03 Jan 2015 05:44:45 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Y7MCH-00040k-5N for help-gnu-emacs@gnu.org; Sat, 03 Jan 2015 05:44:44 -0500 Original-Received: from plane.gmane.org ([80.91.229.3]:35938) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Y7MCG-00040g-UZ for help-gnu-emacs@gnu.org; Sat, 03 Jan 2015 05:44:41 -0500 Original-Received: from list by plane.gmane.org with local (Exim 4.69) (envelope-from ) id 1Y7MCF-0002MH-6z for help-gnu-emacs@gnu.org; Sat, 03 Jan 2015 11:44:39 +0100 Original-Received: from adsl-ull-223-77.49-151.net24.it ([151.49.77.223]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 03 Jan 2015 11:44:39 +0100 Original-Received: from wavexx by adsl-ull-223-77.49-151.net24.it with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Sat, 03 Jan 2015 11:44:39 +0100 X-Injected-Via-Gmane: http://gmane.org/ Original-Lines: 28 Original-X-Complaints-To: usenet@ger.gmane.org X-Gmane-NNTP-Posting-Host: adsl-ull-223-77.49-151.net24.it User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Icedove/31.3.0 In-Reply-To: <83ppax9ndy.fsf@gnu.org> X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 80.91.229.3 X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.14 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.org@gnu.org Original-Sender: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.help:101860 Archived-At: On 01/02/2015 05:07 PM, Eli Zaretskii wrote: >> From: Yuri D'Elia >> Date: Fri, 02 Jan 2015 17:00:31 +0100 >> >>> I think you need to define rules for composing characters into >>> ligatures, in order to have what you want. >> >> This is different than composition of unicode ligatures. >> OTF ligatures are an inherent property of the font along with kerning >> tables. > > I'm probably missing something, and I'm certainly not an expert on OTF > fonts, in Emacs or elsewhere. But if what you want is display several > characters as a single glyph, the way to do that in Emacs is define > composition rules. Composition generates at most a sequence of precomposed utf code points, such as æ. This is done at the client level and is font-agnostic. OTF ligatures instead are glypt replacement tables which are provided for a sequence of characters in the font itself. This is mostly needed to improve the rendering for languages such as arabic. The issue is that it needs special support in the client, since previously drawn glypts might change as a result of typing. I was under the impression that ligatures were supported by looking at `fontset.el'.