From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carsten Dominik Subject: Re: Enriched/Org is a colorful Org Date: Fri, 12 Apr 2013 00:46:02 +0200 Message-ID: <8CA8128C-26D2-49E4-81BF-E68D4EAE83E5@gmail.com> References: <87a9p79gnv.fsf@gmail.com> <20130410095450.GA31506@kuru.dyndns-at-home.com> <83a9p69x0c.fsf@gnu.org> <262C4E11-6D4B-4033-A619-1702CC8D0F94@gmail.com> <83wqs99dv0.fsf@gnu.org> Mime-Version: 1.0 (Mac OS X Mail 6.3 \(1503\)) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Return-path: Received: from eggs.gnu.org ([208.118.235.92]:56455) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UQQFx-0000G1-9C for emacs-orgmode@gnu.org; Thu, 11 Apr 2013 18:46:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UQQFw-00064n-1t for emacs-orgmode@gnu.org; Thu, 11 Apr 2013 18:46:13 -0400 In-Reply-To: <83wqs99dv0.fsf@gnu.org> List-Id: "General discussions about Org-mode." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org Sender: emacs-orgmode-bounces+geo-emacs-orgmode=m.gmane.org@gnu.org To: Eli Zaretskii Cc: emacs-orgmode@gnu.org On 11.4.2013, at 19:27, Eli Zaretskii wrote: > [Please CC me on responses, as I'm not subscribed to this list.] >=20 >> From: Carsten Dominik >> Date: Wed, 10 Apr 2013 21:58:06 +0200 >> Cc: emacs-orgmode@gnu.org >>=20 >>> I beg the Org developers to please be very careful when introducing >>> expensive display features such as overlays into Org. Org already >>> puts the Emacs display engine to its limits in many of its popular >>> features; >>=20 >> this is interesting input, I was not aware of this. Has this been = discussed before, can you point me to relevant threads, and what are the = symptoms of the display engine being at its limits? >=20 > You won't find explicit discussions of this, except maybe a random > comment from me here and there. There aren't too many discussions > about the display engine in general; maybe it's my fault. >=20 > But you can find indirect evidence to what I say in quite a few > reports about slow redisplay. Here's one example (it's just the first > one that popped up on Google): >=20 > http://lists.gnu.org/archive/html/emacs-devel/2011-09/msg00276.html >=20 > Note how two display features: bidi and hl-line -- each one of them > cause significant slow-down in Org buffers, and almost nowhere else. > This is just an example. I keep bumping into similar issues > frequently enough to lead me to the conclusion you see above. Yes, OK, I also remember reports like this. Funny, often it is not Org = by itself, but in combination with something else that affects the = display engine. >=20 > In general, hiding from display large parts of a buffer, and using a > lot of display strings and overlays that add to buffer text or replace > buffer text with something else -- these all make redisplay much more > expensive. In particular, moving overlays disables many redisplay > optimizations, so e.g. any mode that moves overlays as result of > post-command-hook will considerably slow down display and degrade user > experience. OK, this is a concrete thing we can be on the lookout for. I don't = think we do that, but I will take a look. >=20 > After hacking the display code for a few years, it is painfully clear > to me that its basic design assumed that such use cases are rare. Org > mode makes these assumptions more and more false, and it does that > faster than the CPU speed improves ;-) >=20 > For these reasons, and as long as we don't have any development going > on that aims at a complete redesign of the display engine, I think > every feature, especially one expected to be popular, that adversely > impacts redisplay efficiency, should be considered very carefully, and > the various alternatives for its implementation assessed also from > this aspect. This is clear enough. I will try to keep this in mind and evaluate = changes in Org in this way. If you have other concrete things where you = think Org could be improved in this direction, let us know. >=20 > HTH Certainly, thank you. - Carsten=