From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Alan Mackenzie Newsgroups: gmane.emacs.devel Subject: Re: "... the window start at a meaningless point within a line." Date: Thu, 1 Oct 2015 16:35:32 +0000 Message-ID: <20151001163532.GC2515@acm.fritz.box> References: <20150930204513.GA3174@acm.fritz.box> <83mvw39dp3.fsf@gnu.org> <20151001094138.GA2515@acm.fritz.box> <83h9maao7w.fsf@gnu.org> <20151001110204.GB2515@acm.fritz.box> <83egheaj9e.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1443722283 28223 80.91.229.3 (1 Oct 2015 17:58:03 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 1 Oct 2015 17:58:03 +0000 (UTC) Cc: emacs-devel@gnu.org To: Eli Zaretskii Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Oct 01 19:57:55 2015 Return-path: Envelope-to: ged-emacs-devel@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 1Zhi77-0006tU-D9 for ged-emacs-devel@m.gmane.org; Thu, 01 Oct 2015 19:57:53 +0200 Original-Received: from localhost ([::1]:54551 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zhi76-0002A9-UC for ged-emacs-devel@m.gmane.org; Thu, 01 Oct 2015 13:57:52 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:42931) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zhgo6-0007Gr-V9 for emacs-devel@gnu.org; Thu, 01 Oct 2015 12:34:14 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Zhgo3-0004tl-PQ for emacs-devel@gnu.org; Thu, 01 Oct 2015 12:34:10 -0400 Original-Received: from mail.muc.de ([193.149.48.3]:13681) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Zhgo3-0004rT-D7 for emacs-devel@gnu.org; Thu, 01 Oct 2015 12:34:07 -0400 Original-Received: (qmail 74711 invoked by uid 3782); 1 Oct 2015 16:34:03 -0000 Original-Received: from acm.muc.de (p5B14722A.dip0.t-ipconnect.de [91.20.114.42]) by colin.muc.de (tmda-ofmipd) with ESMTP; Thu, 01 Oct 2015 18:34:03 +0200 Original-Received: (qmail 25116 invoked by uid 1000); 1 Oct 2015 16:35:32 -0000 Content-Disposition: inline In-Reply-To: <83egheaj9e.fsf@gnu.org> User-Agent: Mutt/1.5.23 (2014-03-12) 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 X-Received-From: 193.149.48.3 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 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.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:190571 Archived-At: Hello, Eli On Thu, Oct 01, 2015 at 03:03:09PM +0300, Eli Zaretskii wrote: > > Date: Thu, 1 Oct 2015 11:02:04 +0000 > > Cc: emacs-devel@gnu.org > > From: Alan Mackenzie [ .... ] > > This horizontal scrolling (of a long line at the top of W3, when a > > scroll-down brings the beginning of the line onto the window) would be > > precisely what's wanted here. > Then go ahead and make the change. The display engine will cope. I'm > not sure what users will say, but that's not my problem here ;-) Underway. Thus far, I've managed to get all the characters in the broken line displayed "correctly". That was by adding the extra optional parameter to set-window-start, an extra field to struct window, and testing for it in compute_window_start_on_continuation_line. I can scroll the windows, mostly, and this works. So far, so good. But vertical_motion doesn't work properly. (vertical-motion 0) puts point where Emacs thinks the line start ought to be, not where it actually is. I'm looking into this. There may be quite a few places in the code like this. [ .... ] > > Another (lesser) problem is moving point from W2 to W3 with C-x o > > sometimes causes W1 and W2 to scroll up one line; this has the same > > cause. It is suboptimal. > IIUC, you will not be able to fix this. Changes near the boundary > between 2 windows will always be likely to cause some scrolling like > that. :-) > > > > If we were to go this route (of repositioning to avoid line breaks > > > > between follow windows), there would have to be a limit on how far one > > > > could scroll, with a value such as 3. > > > In what units? Screen lines? Why only 3? > > Yes, 3 screen lines. With a command like `scrolldown-n', or C-u 1 > > , the user is requesting a single line scroll. Scrolling more > > than this, even 2 or 3 lines, would be puzzling and irritating. > Not sure if horizontal scrolling will be more or less irritating, but > I guess we will find out soon. We will, hopefully. -- Alan Mackenzie (Nuremberg, Germany).