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.bugs Subject: bug#47712: 27.1; Provide `string-display-width` function, which takes properties into account, `substring-width` Date: Tue, 13 Apr 2021 15:00:35 +0300 Message-ID: <83wnt61jj0.fsf@gnu.org> References: <642c8a37-31c7-2723-12af-06cd7f120c2f@daniel-mendler.de> <83r1jg2q72.fsf@gnu.org> <87h7kbzxwh.fsf@gnus.org> <7c96d858-7947-0cca-60fc-1f6d027bb909@daniel-mendler.de> <87k0p6sjef.fsf@gnus.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="28193"; mail-complaints-to="usenet@ciao.gmane.io" Cc: mail@daniel-mendler.de, 47712@debbugs.gnu.org To: Lars Ingebrigtsen Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Tue Apr 13 14:03:13 2021 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 1lWHlA-0007EA-Lw for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 13 Apr 2021 14:03:12 +0200 Original-Received: from localhost ([::1]:57298 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lWHl9-0005Fm-Mg for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 13 Apr 2021 08:03:11 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:46816) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lWHk2-0004Yt-KL for bug-gnu-emacs@gnu.org; Tue, 13 Apr 2021 08:02:03 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:47580) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lWHk2-0001JV-Cl for bug-gnu-emacs@gnu.org; Tue, 13 Apr 2021 08:02:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1lWHk2-0001zn-AC for bug-gnu-emacs@gnu.org; Tue, 13 Apr 2021 08:02:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 13 Apr 2021 12:02:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 47712 X-GNU-PR-Package: emacs Original-Received: via spool by 47712-submit@debbugs.gnu.org id=B47712.16183152717599 (code B ref 47712); Tue, 13 Apr 2021 12:02:02 +0000 Original-Received: (at 47712) by debbugs.gnu.org; 13 Apr 2021 12:01:11 +0000 Original-Received: from localhost ([127.0.0.1]:59125 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lWHjC-0001yV-Vo for submit@debbugs.gnu.org; Tue, 13 Apr 2021 08:01:11 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:33840) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lWHjA-0001yF-M8 for 47712@debbugs.gnu.org; Tue, 13 Apr 2021 08:01:09 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:47893) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lWHj1-0000hS-DK; Tue, 13 Apr 2021 08:01:02 -0400 Original-Received: from 84.94.185.95.cable.012.net.il ([84.94.185.95]:2988 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1lWHis-0004MG-9a; Tue, 13 Apr 2021 08:00:52 -0400 In-Reply-To: <87k0p6sjef.fsf@gnus.org> (message from Lars Ingebrigtsen on Tue, 13 Apr 2021 10:01:12 +0200) 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:203957 Archived-At: > From: Lars Ingebrigtsen > Cc: Eli Zaretskii , 47712@debbugs.gnu.org > Date: Tue, 13 Apr 2021 10:01:12 +0200 > > Daniel Mendler writes: > > > Note that I would like to have an implementation of > > `substring-width`/`string-display-width`/`substring-display-width` > > which does not allocate, since this reduces the GC pressure when > > formatting many items. How do you think about this? > > > > Regarding images, different fonts, maybe a > > `string-property-pixel-width` would be useful too. But for the use > > cases I have in mind (formatting monospaced text) computing columns is > > sufficient. > > Sure; I think a non-allocating function to count monospaced string width > would be useful. I won't mount the barricades over this, but please keep in mind that even with fixed-pitch fonts this will not always produce correct results, because on GUI frames the "double-width" characters not always take exactly two columns (it depends on the font). So this function will only work reliably on text-mode (a.k.a. TTY) frames and for Latin characters on GUI frames. If you still think we should have such a semi-broken function, at least include some warning in its doc string, so that users wouldn't be unpleasantly surprised.