From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: Scrolling commands and skipping redisplay Date: Sat, 11 Apr 2020 17:04:04 +0000 Message-ID: <20200411170404.GB6682@ACM> References: <542b48ba-4dfa-820f-ba50-4b147ab6d8e2@yandex.ru> <0a5f70aa-4985-8f8d-81d6-6ac4a60a94f9@yandex.ru> <838sj8sphk.fsf@gnu.org> <834ktwsmfw.fsf@gnu.org> <83imibqsmm.fsf@gnu.org> <478c2aab-a5fc-61c2-02e2-2d9846b95273@yandex.ru> <20200411132126.GA6682@ACM> <83pncekug1.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="108319"; mail-complaints-to="usenet@ciao.gmane.io" Cc: rudalics@gmx.at, rrandresf@gmail.com, emacs-devel@gnu.org, rms@gnu.org, dgutov@yandex.ru To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Apr 11 19:05:03 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 1jNJZ1-000S4T-1o for ged-emacs-devel@m.gmane-mx.org; Sat, 11 Apr 2020 19:05:03 +0200 Original-Received: from localhost ([::1]:53750 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jNJZ0-0002C2-4p for ged-emacs-devel@m.gmane-mx.org; Sat, 11 Apr 2020 13:05:02 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:54643) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jNJYD-0001XF-9t for emacs-devel@gnu.org; Sat, 11 Apr 2020 13:04:15 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jNJYB-0002hp-59 for emacs-devel@gnu.org; Sat, 11 Apr 2020 13:04:13 -0400 Original-Received: from colin.muc.de ([193.149.48.1]:40802 helo=mail.muc.de) by eggs.gnu.org with smtp (Exim 4.71) (envelope-from ) id 1jNJYA-0002hj-Sg for emacs-devel@gnu.org; Sat, 11 Apr 2020 13:04:11 -0400 Original-Received: (qmail 72225 invoked by uid 3782); 11 Apr 2020 17:04:10 -0000 Original-Received: from acm.muc.de (p2E5D55B6.dip0.t-ipconnect.de [46.93.85.182]) by localhost.muc.de (tmda-ofmipd) with ESMTP; Sat, 11 Apr 2020 19:04:04 +0200 Original-Received: (qmail 8906 invoked by uid 1000); 11 Apr 2020 17:04:04 -0000 Content-Disposition: inline In-Reply-To: <83pncekug1.fsf@gnu.org> X-Delivery-Agent: TMDA/1.1.12 (Macallan) X-Primary-Address: acm@muc.de X-detected-operating-system: by eggs.gnu.org: FreeBSD 9.x [fuzzy] X-Received-From: 193.149.48.1 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:246841 Archived-At: Hello, Eli. On Sat, Apr 11, 2020 at 16:45:02 +0300, Eli Zaretskii wrote: > > Date: Sat, 11 Apr 2020 13:21:26 +0000 > > From: Alan Mackenzie > > Cc: rudalics@gmx.at, rrandresf@gmail.com, rms@gnu.org, emacs-devel@gnu.org > > > > My personal view: As defaults, I think (i)a and (ii)a are bad, due > > to the long intervals Emacs appears to have hung in. Of (i)b and (ii)b, > > I think (i)b is better, since it avoids the "twinkling" of (ii)b. > > > > I dislike (iii)a,b because of the appearance of non-fontified screens, > > but particularly because the last screen gets fontified in situ after > > first appearing unfontified. I think the non-fontification looks poor > > to a user, even though the scrolling is smooth. > > > > If it were up to me to chose a default setting, I would prefer (i)b, > > closely followed by (ii)b. > Disclosure: I didn't implement any of these options. :-) > I dislike (i)b and (ii)b because they are jerky, and because when I > stop leaning on C-v, I have a lot of screen to watch scrolling, until > Emacs starts executing new commands. I guess my auto-repeat rate is > higher than Alan's. or maybe it's because I'm trying this in a GUI > frame, not a TTY frame. It sounds like your time for scrolling a screen, even without fontification, is close to your auto-repeat time. My repeat rate is 30 characters/second. > My favorite (if one needs to alleviate the default, where Emacs hangs > -- I never actually lean on C-v for prolonged times, except for > testing this very issue) is (iii)a, because it gives me an > uninterrupted scrolling and immediate response once I release C-v. Each one of our sets of (dis)likes is reasonable. That's a strong argument for retaining both jit-lock deferred fontification and fast-but-imprecise-scrolling. What seems not so good is the difficulty a user, on experiencing the problem of 15 second hangs, would have in finding both of the above solutions. What do you think of adding a paragraph like the following after the description of f-b-i-scrolling on the page "Scrolling" in the Emacs manual: As an alternative to setting `fast-but-imprecise-scrolling' you might prefer to enable jit-lock deferred fontification (See Font Lock). To do this, customize `jit-lock-defer-time' to a small positive number such as 0.1. This gives you less jerky scrolling, but the buffer contents on any scroll operation into a fresh portion of the buffer will at first be unfontified, ? -- Alan Mackenzie (Nuremberg, Germany).