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: emacs rendering comparisson between emacs23 and emacs26.3 Date: Wed, 08 Apr 2020 09:45:18 +0300 Message-ID: <83zhbmpjb5.fsf@gnu.org> References: <20200403174757.GA8266@ACM> <20200404104553.GA5329@ACM> <07fe3b69-3ab2-3173-0696-cb17809e2b91@gmx.at> <83blo7v68b.fsf@gnu.org> <1845d7aa-9ae4-3d95-6a30-c7b1d8d8adec@gmx.at> <83a73qt6zs.fsf@gnu.org> <97c4254e-ff43-8402-3645-f713c408c245@gmx.at> <83y2r9syby.fsf@gnu.org> <20200405195753.GG5049@ACM> <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> Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="117584"; mail-complaints-to="usenet@ciao.gmane.io" Cc: acm@muc.de, rrandresf@gmail.com, emacs-devel@gnu.org, rudalics@gmx.at, dgutov@yandex.ru To: rms@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Wed Apr 08 08:46:38 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 1jM4Tu-000UV1-GS for ged-emacs-devel@m.gmane-mx.org; Wed, 08 Apr 2020 08:46:38 +0200 Original-Received: from localhost ([::1]:56662 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jM4Tt-0001M2-Ib for ged-emacs-devel@m.gmane-mx.org; Wed, 08 Apr 2020 02:46:37 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:33738) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jM4Sl-0000UZ-I2 for emacs-devel@gnu.org; Wed, 08 Apr 2020 02:45:28 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:47302) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1jM4Sk-00045n-SU; Wed, 08 Apr 2020 02:45:26 -0400 Original-Received: from [176.228.60.248] (port=4646 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1jM4Sb-0006yZ-U3; Wed, 08 Apr 2020 02:45:19 -0400 In-Reply-To: (message from Richard Stallman on Tue, 07 Apr 2020 22:29:30 -0400) 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-mx.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.io gmane.emacs.devel:246640 Archived-At: > From: Richard Stallman > Cc: dgutov@yandex.ru, acm@muc.de, rrandresf@gmail.com, > emacs-devel@gnu.org, rudalics@gmx.at > Date: Tue, 07 Apr 2020 22:29:30 -0400 > > You've written an extremely clear explanation of how fontification and > scrolling interact. I'm impressed. Thanks. I thought it was important to explain this in so much detail so that everyone interested in this issue will be on the same page. What happens in this use case is quite complex, and many people don't know about these details and therefore are very surprised by some effects of some changes. > > Of course, if fast-but-imprecise-scrolling makes the job of scroll > > commands so much easier that Emacs is capable of keeping up with the > > keyboard auto-repeat rate, then every screen-full you scroll through > > _will_ be displayed, and therefore will be fontified by the calls to > > jit-lock from redisplay itself -- and that will again make scrolling > > slower. So fast-but-imprecise-scrolling is most efficient when it > > makes scroll commands faster, but not too fast... > > I think that is true, if "faster" and "slower" are interpreted in > terms of CPU time used. The CPU time is one major factor, of course. But not the only one, because the keyboard auto-repeat rate is a separate factor which can be controlled and changed independently of the CPU speed. > But if all of that work, including the fontification of each > screenful, is so quick that Emacs never falls behind, I think it > won't seem like "slowness" to the user -- who never has to _wait_ > for it. That's true, to some extent, but my point was that the elapsed time will become slower when each screenful is actually displayed while scrolling. It isn't an important point, though, just a side comment.