From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Question about display engine Date: Wed, 07 Aug 2019 19:12:44 +0300 Message-ID: <83imr9ar9f.fsf@gnu.org> References: <20190807005411.qfzzpz5cjrajbwn2@Ergus> <83o911aukn.fsf@gnu.org> <20190807153220.ssijgjxnf6dszz45@Ergus> <83k1bpasic.fsf@gnu.org> <20190807155738.yviofsumjjhqueci@Ergus> Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="97278"; mail-complaints-to="usenet@blaine.gmane.org" Cc: emacs-devel@gnu.org To: Ergus Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Wed Aug 07 18:13:09 2019 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hvOYj-000P7Q-HE for ged-emacs-devel@m.gmane.org; Wed, 07 Aug 2019 18:13:05 +0200 Original-Received: from localhost ([::1]:43296 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hvOYi-0003Q8-BU for ged-emacs-devel@m.gmane.org; Wed, 07 Aug 2019 12:13:04 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:39200) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1hvOYZ-0003Py-Kc for emacs-devel@gnu.org; Wed, 07 Aug 2019 12:13:00 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:47429) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hvOYY-0002uy-Lh; Wed, 07 Aug 2019 12:12:54 -0400 Original-Received: from [176.228.60.248] (port=4214 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1hvOYX-0003Gg-P5; Wed, 07 Aug 2019 12:12:54 -0400 In-reply-to: <20190807155738.yviofsumjjhqueci@Ergus> (message from Ergus on Wed, 7 Aug 2019 17:57:38 +0200) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:239230 Archived-At: > Date: Wed, 7 Aug 2019 17:57:38 +0200 > From: Ergus > Cc: emacs-devel@gnu.org > > >Such a face will not be a fixed face, it will have to be recomputed > >whenever the face of the text changes, right? E.g., if the face of > >the text specifies some color, you'd want this additional face to have > >the same colors, right? > > > We don't use the face itself, just to merge with the previous glyph. > > >So it doesn't seem to be a face that can be customized in the usual > >sense. We could let the users specify face attributes they don't want > >to see in face extension, though. > > Please look the proposed patch. It may need some improvements, but at > least the functional part is a decent solution for all the issues in my > opinion. First, let's not mix this with the display-fill-column-indicator-mode, let's keep the changes for these two separate, OK? And second, I don't think I understand what we expect users to do with this face's customization. Suppose the user customizes this face to set the :underline attribute, will the effect be reasonable? I thought we wanted to let users determine which attributes will be _reset_, not _set_. But faces, as we use them normally, don't allow resetting attributes. And, of course, this leaves the more general problem I described in my message: what is the right behavior for extending the face that crosses a newline. (Note that the display engine in general doesn't know whether a face that doesn't end before a newline will or won't continue on the next screen line.) Thanks.