From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Werner LEMBERG Newsgroups: gmane.emacs.bugs Subject: bug#31315: wrong font encoding for fallback font Date: Fri, 04 May 2018 07:11:37 +0200 (CEST) Message-ID: <20180504.071137.973726089728856021.wl@gnu.org> References: <83a7tgpr43.fsf@gnu.org> <20180503.210528.278141526929157986.wl@gnu.org> <83vac4o6hr.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Trace: blaine.gmane.org 1525410609 29060 195.159.176.226 (4 May 2018 05:10:09 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Fri, 4 May 2018 05:10:09 +0000 (UTC) Cc: 31315@debbugs.gnu.org To: eliz@gnu.org Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Fri May 04 07:10:05 2018 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1fESyq-0007Sm-Sv for geb-bug-gnu-emacs@m.gmane.org; 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Fri, 04 May 2018 07:11:39 +0200 In-Reply-To: <83vac4o6hr.fsf@gnu.org> X-Mailer: Mew version 6.7 on Emacs 27.0.50 / Mule 6.0 (HANACHIRUSATO) X-Provags-ID: V03:K1:osI4cqr0lxZmHfJkVVGRTe1uxDp82MPQlcTsOFd29GpOTNL/QDI Gav0HYWEPdWIeS0O8nhbdpfAalYnvEk9s8DHFgBsklpPNtWuwGKmNtLg1IDtcLsA5N97Umy riPQAkvQJGMX9B6beUpqMytya1l5TQk1XxlIk/v45yy5UXQs2tQ3L6hv2DN0sXC0geiuP7b KBmiLHJGWoNXSZTCgO2kw== X-UI-Out-Filterresults: notjunk:1;V01:K0:o95lyWyVVl8=:8S2/qHmZHJQ3olG1qcsTIo Qt9Q2Hb3lzrHz9EsAObXbYQZeGv6cQy00vfeeSyp2KI50iHWqWAI7czfe6JlH7duVv/Iz4dGa g8ZCwAv/rVbYzu5oIcDIf2ZcJM28ND2wsew9VzK3M8fIbClSt2dUvm9TPKZjxzT4yHHrp6pZ+ y2shvJNH8WZbCQxQR0NgZ44wBIKxC1/vQJup1WqPEB/78zSM2qgn6hXcO2lMWupMbQIDKedAX gtbHYJHhI0ipnnULlueJU6E655lOM46UWChvlhdneprLjXAIFI17hPMZjUb2jZh2Qcwi24FFy X0VzErurGyqSaFPJtkbLgW1hWxxuIMHUiUWh7MavIoGlghFrFr7tLZOJe1MgvUdxfU5Gn9LIv 0XL9tuLadS+SrwM3PxmyBp9vu5k7cJ895Gso9cJ9H2LYYx4KEFTKVB8eRxIdrI6w4DySNSoZh LhdVyzM7tmCw6mdB90foQjijYvecI+dA2kxQCZkMDCZoo2VIrH1LlS10aTtWjv4ECb7ynI+sQ gNU3euZo9HqVOQWEQ7vVOcSmSrJT14eATHPbC04c70LQzozkaAsb1KUwwZduH2o9AKjBJ32ZI x62XBkg1oDNgX9CVoapLt7njM1kBha8aBWszPp83YHqgAxehvvsxYJ1lcLCxdJmzQDd9PNpDa 2yJMx8ksJKgUJZEYGCeC77cm2rZiDjwCIFfBZWda/hkKf1N4vKteobtUQSDh0wY0+wzUW2sv4 JTb8Y8Ki1xiZlJVDHxO1xr6HwVDvXq1VsDW+XsjX8jXAm/VqWxEhj62fnCwY4E4elZhZC0Dt X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:146001 Archived-At: >> Alas, my Elisp knowledge is ... well ... not impressive. >> Basically, I'm just an Emacs user, not an Emacs developer. > > Almost all of the relevant code is in C, not in Lisp. OK. >> With Xft, there is no possibility for improvement IMHO. The >> probably best choice is to switch to Pango for font access (in case >> you don't do that already). > > There are several back-ends besides Xft, the most advanced being > xftfont.c. They all didn't see any serious development for the past > several years. And yes, acquiring new back-ends is also a worthy > goal. > > All of that requires a level of expertise that IMO we currently > don't have. What I can certainly offer is advice. However, I'm not sure to be right person for working on the innards of Emacs, given the usual lack of time (sigh). >> An Emacs charset essentially triggers a language and script >> setting, and those two parameters can be passed to Pango, AFAIK. > > Emacs handles charsets and scripts separately. A script is matched > against OTF/TTF features of fonts to make sure the necessary shaping > features required by a script are supported. Interesting. Access to OpenType features is exactly what's needed to improve font display for selected charsets. Where can I find the related code in Emacs? Additionally, I suggest that the Emacs maintainers set up a GSoC project, namely to improve font rendering. This is a broad topic, which could be further split into smaller subprojects. Emacs uses Handa-san's libotf library (are there any other projects that use this library?), but AFAICS it doesn't receive a lot of testing. On the other hand, there is Behdad Esfahbod's `HarfBuzz' shaping engine that comes with a large suite of tests. One of such subprojects could be to take these tests and use them to improve libotf, especially for Indic scripts. https://www.freedesktop.org/wiki/Software/HarfBuzz/ Werner