From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Alan Third Newsgroups: gmane.emacs.bugs Subject: bug#41187: 28.0.50; Flipped text Date: Thu, 14 May 2020 22:05:57 +0100 Message-ID: <20200514210557.GD50681@breton.holly.idiocy.org> References: <9825B211-9633-47CC-9631-A516387ADDB5@gmail.com> <83k11ibimr.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="118899"; mail-complaints-to="usenet@ciao.gmane.io" Cc: Wasim Abbas , 41187@debbugs.gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Thu May 14 23:07:10 2020 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jZL4P-000Uo7-Ls for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 14 May 2020 23:07:09 +0200 Original-Received: from localhost ([::1]:55564 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jZL4O-0002gK-NX for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 14 May 2020 17:07:08 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:47110) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jZL4I-0002gB-Tk for bug-gnu-emacs@gnu.org; Thu, 14 May 2020 17:07:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:51757) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jZL4I-0008Id-Ka for bug-gnu-emacs@gnu.org; Thu, 14 May 2020 17:07:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jZL4I-0004u8-F5 for bug-gnu-emacs@gnu.org; Thu, 14 May 2020 17:07:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Alan Third Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 14 May 2020 21:07:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 41187 X-GNU-PR-Package: emacs Original-Received: via spool by 41187-submit@debbugs.gnu.org id=B41187.158949037318787 (code B ref 41187); Thu, 14 May 2020 21:07:02 +0000 Original-Received: (at 41187) by debbugs.gnu.org; 14 May 2020 21:06:13 +0000 Original-Received: from localhost ([127.0.0.1]:35070 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jZL3R-0004sn-Nn for submit@debbugs.gnu.org; Thu, 14 May 2020 17:06:13 -0400 Original-Received: from idiocy.org ([217.169.17.33]:54226 helo=breton.holly.idiocy.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jZL3L-0004s5-NE for 41187@debbugs.gnu.org; Thu, 14 May 2020 17:06:08 -0400 Original-Received: by breton.holly.idiocy.org (Postfix, from userid 501) id E3FB12022C7871; Thu, 14 May 2020 22:05:57 +0100 (BST) Mail-Followup-To: Alan Third , Eli Zaretskii , Wasim Abbas , 41187@debbugs.gnu.org Content-Disposition: inline In-Reply-To: <83k11ibimr.fsf@gnu.org> X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list 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-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:180279 Archived-At: On Mon, May 11, 2020 at 06:23:24PM +0300, Eli Zaretskii wrote: > > From: Wasim Abbas > > Date: Mon, 11 May 2020 13:00:57 +0100 > > > > I am seeing this issue on emacs head. The text randomly flips vertically. Very hard to reproduce. But if you open a very long C/C++ file like https://github.com/KhronosGroup/Vulkan-Headers/blob/master/include/vulkan/vulkan_core.h and keep moving around the buffer, cut 100ish lines and paste in another location and then move around again. You might hit the issue. > > > > Here is a screenshot of it. I haven’t tried with emacs -Q yet but happy to try if required. > > Wow! That's got to be some weird problem with you video driver or the > display hardware. Emacs never does anything like that. It's almost definitely related to the fact that the NS port now draws to an offscreen buffer on macOS 10.14 and above. Unfortunately the macOS GUI toolkit has a reversed y axis as compared to what the Emacs code expects. This means there are a number of places where we have to invert the offscreen buffer, but I can't imagine a situation where we're failing to invert it that wouldn't show up in normal usage. There must be some specific situation that's catching it out. -- Alan Third