From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#41645: 27.0.91; Combining Grapheme Joiner (#x34f) gui artifacts Date: Mon, 01 Jun 2020 21:37:38 +0300 Message-ID: <83lfl6eiod.fsf@gnu.org> References: <83zh9merd4.fsf@gnu.org> <83wo4qepab.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="6209"; mail-complaints-to="usenet@ciao.gmane.io" Cc: dfussner@googlemail.com, 41645@debbugs.gnu.org To: Pip Cet Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Mon Jun 01 20:38:09 2020 Return-path: Envelope-to: geb-bug-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 1jfpK5-0001VR-Lo for geb-bug-gnu-emacs@m.gmane-mx.org; Mon, 01 Jun 2020 20:38:09 +0200 Original-Received: from localhost ([::1]:51532 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jfpK4-0006dq-N1 for geb-bug-gnu-emacs@m.gmane-mx.org; Mon, 01 Jun 2020 14:38:08 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:41862) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jfpJy-0006ba-6b for bug-gnu-emacs@gnu.org; Mon, 01 Jun 2020 14:38:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:53690) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jfpJx-00005F-TZ for bug-gnu-emacs@gnu.org; Mon, 01 Jun 2020 14:38:01 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jfpJx-0004JC-PU for bug-gnu-emacs@gnu.org; Mon, 01 Jun 2020 14:38:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 01 Jun 2020 18:38:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 41645 X-GNU-PR-Package: emacs Original-Received: via spool by 41645-submit@debbugs.gnu.org id=B41645.159103667216547 (code B ref 41645); Mon, 01 Jun 2020 18:38:01 +0000 Original-Received: (at 41645) by debbugs.gnu.org; 1 Jun 2020 18:37:52 +0000 Original-Received: from localhost ([127.0.0.1]:37003 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jfpJo-0004Ip-Jo for submit@debbugs.gnu.org; Mon, 01 Jun 2020 14:37:52 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:34404) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jfpJm-0004Ic-Qm for 41645@debbugs.gnu.org; Mon, 01 Jun 2020 14:37:51 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:54669) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jfpJh-0008VO-CV; Mon, 01 Jun 2020 14:37:45 -0400 Original-Received: from [176.228.60.248] (port=4644 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1jfpJg-0003hX-Qo; Mon, 01 Jun 2020 14:37:45 -0400 In-Reply-To: (message from Pip Cet on Mon, 1 Jun 2020 18:09:27 +0000) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list 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-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:181364 Archived-At: > From: Pip Cet > Date: Mon, 1 Jun 2020 18:09:27 +0000 > Cc: dfussner@googlemail.com, 41645@debbugs.gnu.org > > The problem is a zero-width glyph in a gstring. Fixing the artifact is > easy (see attached patch), but that still means when the cursor is on > the CGJ it's invisible. My impression is most code paths avoid > zero-width glyphs for that reason. Sorry, I don't follow. The composition-function-table entry for CGJ is this: (aref composition-function-table #x34f) => (["\\c.\\c^+" 1 compose-gstring-for-graphic] [nil 0 compose-gstring-for-graphic]) So CGJ is supposed to be composed with the previous character, similarly to diacritics. When the composition happens, what glyphs are returned from the shaper? On my system, with a font that supports that character, if I type "a b c d CGJ x y z" (without the spaces), I see just "abcdxyz" with nothing between d and x, not even a thin space. And "C-u C-x =" on d then reports: position: 149 of 153 (97%), column: 3 character: d (displayed as d) (codepoint 100, #o144, #x64) charset: ascii (ASCII (ISO646 IRV)) code point in charset: 0x64 script: latin syntax: w which means: word category: .:Base, L:Left-to-right (strong), a:ASCII, l:Latin, r:Roman to input: type "C-x 8 RET 64" or "C-x 8 RET LATIN SMALL LETTER D" buffer code: #x64 file code: #x64 (encoded by coding system iso-latin-1-dos) display: composed to form "d͏" (see below) Composed with the following character(s) "͏" using this font: harfbuzz:-outline-Code2000-normal-normal-normal-*-16-*-*-*-p-*-iso8859-1 by these glyphs: [0 1 100 71 10 0 9 11 0 nil] [0 1 847 3 6 0 1 0 1 [0 0 0]] Is what you see on your system similar? If so, which glyph is zero-width, and why does it cause trouble on your system, but not on mine? > Indeed, the composition gstring is a single zero-width glyph. See the composition information above: my interpretation of it is that the composed glyph is not zero-width. > How about this, as a first stop-gap until we figure out how to > properly prevent automatic compositions resulting in zero-width struct > glyphs? Not sure yet. I need to understand the problem better before I have an opinion about the proposed change.