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: Sat, 11 Apr 2020 10:55:29 +0300 Message-ID: <83zhbilamm.fsf@gnu.org> References: <20200403174757.GA8266@ACM> <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> <478c2aab-a5fc-61c2-02e2-2d9846b95273@yandex.ru> <83v9m9nltx.fsf@gnu.org> <4c5ebff1-39ab-3d63-6118-42befc93b862@yandex.ru> <6914ebb2-2dfa-efdc-1181-c42259219bca@yandex.ru> <83zhbjna0q.fsf@gnu.org> <903b7d31-bd0e-e2dc-a981-d090ed959ccb@yandex.ru> <83pncfmpme.fsf@gnu.org> <94ee576f-ff26-cad9-3e22-b75299ff9cdb@yandex.ru> <83h7xrmjg3.fsf@gnu.org> <2ae375b2-da26-5525-603a-73133fda432d@yandex.ru> Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="84258"; mail-complaints-to="usenet@ciao.gmane.io" Cc: rms@gnu.org, emacs-devel@gnu.org, rudalics@gmx.at, rrandresf@gmail.com, monnier@iro.umontreal.ca, acm@muc.de To: Dmitry Gutov Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sat Apr 11 09:56:55 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 1jNB0Z-000Lq8-AU for ged-emacs-devel@m.gmane-mx.org; Sat, 11 Apr 2020 09:56:55 +0200 Original-Received: from localhost ([::1]:49708 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jNB0Y-0003US-AU for ged-emacs-devel@m.gmane-mx.org; Sat, 11 Apr 2020 03:56:54 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:33698) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jNAzf-0002gK-VW for emacs-devel@gnu.org; Sat, 11 Apr 2020 03:56:01 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:40382) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1jNAze-0001qg-0J; Sat, 11 Apr 2020 03:55:58 -0400 Original-Received: from [176.228.60.248] (port=3538 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1jNAzR-0000u3-Hr; Sat, 11 Apr 2020 03:55:45 -0400 In-Reply-To: <2ae375b2-da26-5525-603a-73133fda432d@yandex.ru> (message from Dmitry Gutov on Sat, 11 Apr 2020 03:21:52 +0300) 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:246821 Archived-At: > Cc: monnier@iro.umontreal.ca, acm@muc.de, rrandresf@gmail.com, > emacs-devel@gnu.org, rms@gnu.org, rudalics@gmx.at > From: Dmitry Gutov > Date: Sat, 11 Apr 2020 03:21:52 +0300 > > > What else could be the reason of differences between what we see on > > our respective systems? > > Maybe the fact that you see updating the highlighting after the text has > been displayed as okay, and I don't. It feels like flickering to me, a > visual aggravation. Thus, if I see that during scrolling, it's also > "flickering". That's not flickering, at least not in our accepted terminology. Flickering is redrawing of the entire frame, without any changes to the contents. That's not what happens here: Emacs only redraws the parts that have non-default colors, and it doesn't redraw the tool bar, the menu bar, and the mode line (only the line number and the percent are updated in the mode line). > > Showing unfontified text _is_ the intended effect of > > jit-lock-defer-time. On slow machines, I fail to see how this could > > be worse than having Emacs hang for many seconds. > > There can be other options. > > And on *very slow* machines, okay, that can be a solution. Even so, a > low enough machine might not keep up with scrolling even if font-lock is > skipped, so it's not a panacea. On such slow machines, fast-but-imprecise-scrolling is not a solution, either; IME it actually is worse than jit-lock-defer-time. > >> And I'd hesitate to recommend it to anyone even to deal with > >> performance problems. > > > > Not sure why would you hesitate. > > Because it feels like giving up. "Here's a solution, please disregard > that it comes with obvious downsides". What are the alternatives? If the system is slow, we must cause Emacs do less so that it doesn't appear as hanging up. > If you go back to my last patch and try it, you might see that both the > default behavior, as well as the new behavior with f-b-i-s on, *look* > more responsive. Perhaps with optimized builds on your fast machine, they do. But we are specifically discussing slow systems here. > None of it deals with keyboard auto-repeat. On the other hand, having > input keys fire as fast as they can is not a hard requirement. Keyboard auto-repeat (or the equivalent repeated turning of the mouse wheel) was what started this thread. Let's not change the subject. > Ideally, > Emacs should stop scrolling as soon as I release the 'v' key. No matter > how many screenfuls it had managed to scroll through in the meantime. jit-lock-defer-time satisfies this requirement, at least here, whereas fast-but-imprecise-scrolling doesn't. > (And there are other commands where such behavior would also be preferable). Which commands are those? Are you sure the current discussion about jit-lock and its slowdown is relevant for explaining the slowdown of those commands?