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.devel Subject: Re: Scrolling commands and skipping redisplay, was: Re: emacs rendering comparisson between emacs23 and emacs26.3 Date: Wed, 22 Apr 2020 16:26:36 +0300 Message-ID: <835zdrfy7n.fsf@gnu.org> References: <20200403174757.GA8266@ACM> <83zhbcdmyi.fsf@gnu.org> <61f565cd-4fee-d48c-a9ef-b78419b3d058@yandex.ru> <83wo6ed4kb.fsf@gnu.org> <464b5639-7790-fdbc-b519-22a6b0e8c016@yandex.ru> <83o8rqaucp.fsf@gnu.org> <551c7634-f614-c5a7-c089-33a0dc56574d@yandex.ru> <83imhyaqyw.fsf@gnu.org> <3ddcec07-079f-18e8-81a7-76eaf9a8187a@yandex.ru> <83d083ia16.fsf@gnu.org> <83y2qqgrr6.fsf@gnu.org> <837dyagkwm.fsf@gnu.org> <532544ab-55ec-aab9-1c2f-fa0081332401@yandex.ru> <834ktegivn.fsf@gnu.org> <83y2qqf29e.fsf@gnu.org> <83tv1eezyi.fsf@gnu.org> <83r1whezor.fsf@gnu.org> Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="86753"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org, rudalics@gmx.at, rrandresf@gmail.com, monnier@iro.umontreal.ca, dgutov@yandex.ru, acm@muc.de To: rms@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Apr 22 15:28:12 2020 Return-path: Envelope-to: ged-emacs-devel@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 1jRFQC-000MVU-HC for ged-emacs-devel@m.gmane-mx.org; Wed, 22 Apr 2020 15:28:12 +0200 Original-Received: from localhost ([::1]:50568 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jRFQB-0004QN-K2 for ged-emacs-devel@m.gmane-mx.org; Wed, 22 Apr 2020 09:28:11 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:55976) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jRFP8-0003CB-Ar for emacs-devel@gnu.org; Wed, 22 Apr 2020 09:27:18 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:58479) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jRFP6-0005c7-RR; Wed, 22 Apr 2020 09:27:04 -0400 Original-Received: from [176.228.60.248] (port=3386 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1jRFOw-00083A-VC; Wed, 22 Apr 2020 09:26:55 -0400 In-Reply-To: (message from Richard Stallman on Tue, 21 Apr 2020 23:14:07 -0400) 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:247509 Archived-At: > From: Richard Stallman > Cc: monnier@iro.umontreal.ca, dgutov@yandex.ru, acm@muc.de, > rrandresf@gmail.com, emacs-devel@gnu.org, rudalics@gmx.at > Date: Tue, 21 Apr 2020 23:14:07 -0400 > > > That would mean the last line we scroll into the window will be only > > partially visible, and that is a no-no in scrolling. > > It is somewhat undesirable, but I am not convinced it must be > absolutely rejected. That's currently a very significant requirement throughout redisplay_window and its subroutine: any result that leaves the current line (i.e. the line where point is) not completely visible is rejected, and we select some other window-start point to avoid that. It's possible to toss this requirement, of course, but then a lot of existing code in the display engine will have to be rewritten, because I won't be surprised if the assumption that this holds is implicitly made by some parts of the display code.