From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#9771: 24.0.90; Redisplay problems with control characters Date: Mon, 17 Oct 2011 10:18:42 -0400 Message-ID: References: <871uucr2w1.fsf@gnu.org> Reply-To: Eli Zaretskii NNTP-Posting-Host: lo.gmane.org X-Trace: dough.gmane.org 1318861163 11926 80.91.229.12 (17 Oct 2011 14:19:23 GMT) X-Complaints-To: usenet@dough.gmane.org NNTP-Posting-Date: Mon, 17 Oct 2011 14:19:23 +0000 (UTC) To: bojohan@gnu.org, 9771@debbugs.gnu.org Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Mon Oct 17 16:19:19 2011 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([140.186.70.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1RFo2B-0001uh-AA for geb-bug-gnu-emacs@m.gmane.org; Mon, 17 Oct 2011 16:19:19 +0200 Original-Received: from localhost ([::1]:37576 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RFo2A-00080u-O5 for geb-bug-gnu-emacs@m.gmane.org; Mon, 17 Oct 2011 10:19:18 -0400 Original-Received: from eggs.gnu.org ([140.186.70.92]:54110) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RFo28-00080b-Ax for bug-gnu-emacs@gnu.org; Mon, 17 Oct 2011 10:19:17 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1RFo22-00079n-E7 for bug-gnu-emacs@gnu.org; Mon, 17 Oct 2011 10:19:16 -0400 Original-Received: from debbugs.gnu.org ([140.186.70.43]:35546) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1RFo22-00079i-9b for bug-gnu-emacs@gnu.org; Mon, 17 Oct 2011 10:19:10 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.69) (envelope-from ) id 1RFo2r-0001PH-LJ for bug-gnu-emacs@gnu.org; Mon, 17 Oct 2011 10:20:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: debbugs-submit-bounces@debbugs.gnu.org Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 17 Oct 2011 14:20:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 9771 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 9771-submit@debbugs.gnu.org id=B9771.13188611775371 (code B ref 9771); Mon, 17 Oct 2011 14:20:01 +0000 Original-Received: (at 9771) by debbugs.gnu.org; 17 Oct 2011 14:19:37 +0000 Original-Received: from localhost ([127.0.0.1] helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1RFo2T-0001Oa-81 for submit@debbugs.gnu.org; Mon, 17 Oct 2011 10:19:37 -0400 Original-Received: from fencepost.gnu.org ([140.186.70.10]) by debbugs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1RFo2Q-0001OP-D6 for 9771@debbugs.gnu.org; Mon, 17 Oct 2011 10:19:35 -0400 Original-Received: from eliz by fencepost.gnu.org with local (Exim 4.71) (envelope-from ) id 1RFo1a-00079e-Kw; Mon, 17 Oct 2011 10:18:42 -0400 In-reply-to: (message from Eli Zaretskii on Mon, 17 Oct 2011 03:48:27 -0400) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.11 Precedence: list Resent-Date: Mon, 17 Oct 2011 10:20:01 -0400 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) X-Received-From: 140.186.70.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.bugs:52716 Archived-At: > Date: Mon, 17 Oct 2011 03:48:27 -0400 > From: Eli Zaretskii > Cc: 9771@debbugs.gnu.org > > > 3. Long lines with display vectors make Emacs really slow (with bidi) > > It's not the display vectors in general that cause this. It's > specifically the display of control characters. The reason for the slowness is the bidirectional property of the control characters, and a peculiarity of the UBA, the Unicode Bidirectional Algorithms, regarding the processing of sequences of characters with that particular property. In the particular case in point, it causes Emacs to search to the end of the long line, when it is about to display the first null character. So now this question becomes very relevant: > is there some real-life use case behind your recipe? Depending on the answer, it may or may not be a good idea to look for some heuristics for this case before 24.1 is released, because AFAICS the current implementation of the UBA requirements is correct.