From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#46556: 27.1; transparent images are displayed incorrectly if rotated Date: Wed, 17 Feb 2021 19:05:38 +0200 Message-ID: <83blci7hgd.fsf@gnu.org> References: <86mtw4tiyg.fsf@gmail.com> <87sg5ww430.fsf@gnus.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="7031"; mail-complaints-to="usenet@ciao.gmane.io" Cc: larsi@gnus.org, ynyaaa@gmail.com, 46556@debbugs.gnu.org To: Alan Third Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Wed Feb 17 18:14:45 2021 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 1lCQPV-0001k5-N9 for geb-bug-gnu-emacs@m.gmane-mx.org; Wed, 17 Feb 2021 18:14:45 +0100 Original-Received: from localhost ([::1]:56580 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lCQPU-0004D2-OC for geb-bug-gnu-emacs@m.gmane-mx.org; Wed, 17 Feb 2021 12:14:44 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:39320) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lCQH4-0005Wh-Pt for bug-gnu-emacs@gnu.org; Wed, 17 Feb 2021 12:06:02 -0500 Original-Received: from debbugs.gnu.org ([209.51.188.43]:33256) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1lCQH4-00005C-Dp for bug-gnu-emacs@gnu.org; Wed, 17 Feb 2021 12:06:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1lCQH4-0007Bc-6z for bug-gnu-emacs@gnu.org; Wed, 17 Feb 2021 12:06:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Wed, 17 Feb 2021 17:06:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 46556 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: moreinfo Original-Received: via spool by 46556-submit@debbugs.gnu.org id=B46556.161358154027589 (code B ref 46556); Wed, 17 Feb 2021 17:06:02 +0000 Original-Received: (at 46556) by debbugs.gnu.org; 17 Feb 2021 17:05:40 +0000 Original-Received: from localhost ([127.0.0.1]:44800 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lCQGh-0007Au-Me for submit@debbugs.gnu.org; Wed, 17 Feb 2021 12:05:39 -0500 Original-Received: from eggs.gnu.org ([209.51.188.92]:49542) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1lCQGf-0007AQ-LG for 46556@debbugs.gnu.org; Wed, 17 Feb 2021 12:05:38 -0500 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:50325) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lCQGY-0008RF-EQ; Wed, 17 Feb 2021 12:05:32 -0500 Original-Received: from 84.94.185.95.cable.012.net.il ([84.94.185.95]:1296 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1lCQGX-0008Hc-Md; Wed, 17 Feb 2021 12:05:30 -0500 In-Reply-To: (message from Alan Third on Tue, 16 Feb 2021 21:24:24 +0000) 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:200207 Archived-At: > Date: Tue, 16 Feb 2021 21:24:24 +0000 > From: Alan Third > Cc: ynyaaa@gmail.com, 46556@debbugs.gnu.org > > > Would it be possible for you to test with Emacs 28 and see whether the > > problem you report (on Windows) is still present there? > > It does sound like something must be going wrong on Windows. > Unfortunately I don't know what that could be because, as I said on > the other bug report, NS and Windows use the same rotation logic, and > NS is fine, so it must be when it comes to actually drawing that the > problem manifests. I've now stepped through the code which implements rotation, and I see nothing wrong with the results. The pixel coordinates of the rotated square are exact and accurate, without any roundoff that I could spot. Each square starts exactly 50+8 = 58 pixels after the previous one (8 pixels are taken by the SPC character between the squares), and ends exactly 50 pixels after it starts. So I have no idea why the one-pixel shift happens. Of course, I don't really understand what that code does (although I hacked it quite extensively), so maybe someone who really understands that stuff could take a look and tell what's wrong there.