From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#28312: 25.2; Arabic script changes when scrolling Date: Mon, 10 Jun 2019 20:27:02 +0300 Message-ID: <83pnnl9wrd.fsf@gnu.org> References: <83lgly29zf.fsf@gnu.org> <83h8wm24v9.fsf@gnu.org> <834l52stcy.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="108010"; mail-complaints-to="usenet@blaine.gmane.org" Cc: 28312@debbugs.gnu.org To: Nick Helm Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Mon Jun 10 19:28:30 2019 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([209.51.188.17]) by blaine.gmane.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1haO5t-000Rv4-Lr for geb-bug-gnu-emacs@m.gmane.org; Mon, 10 Jun 2019 19:28:29 +0200 Original-Received: from localhost ([::1]:48558 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1haO5s-0006mu-3X for geb-bug-gnu-emacs@m.gmane.org; Mon, 10 Jun 2019 13:28:28 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:55038) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1haO5c-0006ml-9j for bug-gnu-emacs@gnu.org; Mon, 10 Jun 2019 13:28:14 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1haO5U-0001nd-Q6 for bug-gnu-emacs@gnu.org; Mon, 10 Jun 2019 13:28:08 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:43913) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1haO5S-0001mU-PM for bug-gnu-emacs@gnu.org; Mon, 10 Jun 2019 13:28:04 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1haO5S-00080D-FG for bug-gnu-emacs@gnu.org; Mon, 10 Jun 2019 13:28:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 10 Jun 2019 17:28:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 28312 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: patch Original-Received: via spool by 28312-submit@debbugs.gnu.org id=B28312.156018764230694 (code B ref 28312); Mon, 10 Jun 2019 17:28:02 +0000 Original-Received: (at 28312) by debbugs.gnu.org; 10 Jun 2019 17:27:22 +0000 Original-Received: from localhost ([127.0.0.1]:57457 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1haO4n-0007yz-NC for submit@debbugs.gnu.org; Mon, 10 Jun 2019 13:27:21 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:46092) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1haO4k-0007yl-Ev for 28312@debbugs.gnu.org; Mon, 10 Jun 2019 13:27:20 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:55180) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1haO4d-0001Gm-N5; Mon, 10 Jun 2019 13:27:11 -0400 Original-Received: from [176.228.60.248] (port=1542 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1haO4Y-0000G2-Dn; Mon, 10 Jun 2019 13:27:09 -0400 In-reply-to: (message from Nick Helm on Sun, 9 Jun 2019 23:56:22 +0000) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.51.188.43 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" Xref: news.gmane.org gmane.emacs.bugs:160335 Archived-At: > From: Nick Helm > CC: "mituharu@math.s.chiba-u.ac.jp" , > "handa@gnu.org" , "28312@debbugs.gnu.org" > <28312@debbugs.gnu.org> > Date: Sun, 9 Jun 2019 23:56:22 +0000 > > > Would people please try the patch and see if Emacs is still reasonably > > responsive in buffers with Arabic text, especially when marking or > > extending the region under transient-mark-mode? If I get enough > > positive feedback, I will install this. TIA. > > I built yesterday's master and tested with and without the patch. > > With the patch applied, I can confirm that the Arabic text in HELLO no > longer changes when scrolling, either with the keyboard or mouse. Thanks for testing. > However, I noticed that it still seems to change when extending the > region over Arabic text. That is, place point on the "c" of Arabic, > C-SPC, and C-f multiple times to extend the region and notice the > graphemes change. The mouse click and release method described up-thread > also shows the same thing. This is a separate problem, one whose solution would basically need redesigning how we handle faces in redisplay. The problem is that we currently process buffer text for display in chunks that have the same face, so if the region starts or ends in the middle of an Arabic word, we submit this word to the shaping engine in 2 chunks, thus breaking character composition. This is very basic in the display engine's design, so don't hold your breath on that one. > Next, I opened a file written entirely in Arabic (~3000 words). Without > the patch, scrolling works as expected in all cases I tried. With the > patch applied, scrolling also works as expected unless pixel-scroll-mode > is active and scrolling is done with the mouse. With that mode active, > mouse scrolling introduces lag that takes 3–4 seconds to recover after > each scroll action. I would describe the lag as significant. I did not > notice the text changing when scrolling or clicking in this file. I'm working on a less expensive solution, stay tuned.