From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.help Subject: Re: visual-line-mode produces erratic behaviour with text properties Date: Fri, 01 Jul 2016 12:29:54 +0300 Message-ID: <83wpl5u2nh.fsf@gnu.org> References: <1467351025.3299202.653866593.5B4EE9EF@webmail.messagingengine.com> <831t3dvlm3.fsf@gnu.org> <1467361780.3331730.653970465.54AC12BD@webmail.messagingengine.com> NNTP-Posting-Host: plane.gmane.org X-Trace: ger.gmane.org 1467365459 10149 80.91.229.3 (1 Jul 2016 09:30:59 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Fri, 1 Jul 2016 09:30:59 +0000 (UTC) To: help-gnu-emacs@gnu.org Original-X-From: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Fri Jul 01 11:30:51 2016 Return-path: Envelope-to: geh-help-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1bIume-00069D-Ol for geh-help-gnu-emacs@m.gmane.org; Fri, 01 Jul 2016 11:30:48 +0200 Original-Received: from localhost ([::1]:60660 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bIumZ-0003zX-3v for geh-help-gnu-emacs@m.gmane.org; Fri, 01 Jul 2016 05:30:43 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:54314) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bIumB-0003w1-4k for help-gnu-emacs@gnu.org; Fri, 01 Jul 2016 05:30:19 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bIum6-0001Ad-0v for help-gnu-emacs@gnu.org; Fri, 01 Jul 2016 05:30:17 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:55589) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bIum5-00019t-TX for help-gnu-emacs@gnu.org; Fri, 01 Jul 2016 05:30:13 -0400 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:1426 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1bIum3-0007cd-MR for help-gnu-emacs@gnu.org; Fri, 01 Jul 2016 05:30:12 -0400 In-reply-to: <1467361780.3331730.653970465.54AC12BD@webmail.messagingengine.com> (message from Paul Rankin on Fri, 01 Jul 2016 18:29:40 +1000) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-BeenThere: help-gnu-emacs@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Users list for the GNU Emacs text editor List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-gnu-emacs-bounces+geh-help-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "help-gnu-emacs" Xref: news.gmane.org gmane.emacs.help:110684 Archived-At: > From: Paul Rankin > Date: Fri, 01 Jul 2016 18:29:40 +1000 > > On Fri, 1 Jul 2016, at 05:55 PM, Eli Zaretskii wrote: > > Super-long lines such as this one slow down the display engine, and > > there are various redisplay optimizations to try to countermand that, > > so perhaps this is one of them. > > Do you mean Emacs has redisplay optimisations that may be causing the erratic navigation? Yes, at least in principle. > Or, are there redisplay optimisations I can implement myself in an affected major mode to work around this? That's not the way to deal with these problems. If some redisplay optimization causes incorrect display in some use case, it should be disabled in that use case. IOW, it's a bug that needs to be fixed, not worked around in application code. > > In general, my recommendation is to stay away of such long lines in > > Emacs. > > I can't control this for users of the major mode. It's an edge case, but still. That recommendation was mainly for end-users, not for developers. Of course, if you can come up with an implementation that avoids long lines, you as developer should prefer it, but I understand this is not such a case.