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#44120: 28.0.50; Animated GIFs sometimes leave "trails" Date: Thu, 22 Oct 2020 15:54:29 +0300 Message-ID: <835z72mnei.fsf@gnu.org> References: <873627jsmv.fsf@gnus.org> <20201021200842.GB47992@breton.holly.idiocy.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="37361"; mail-complaints-to="usenet@ciao.gmane.io" Cc: larsi@gnus.org, 44120@debbugs.gnu.org To: Alan Third Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Thu Oct 22 14:55:12 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 1kVa7b-0009bD-LH for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 22 Oct 2020 14:55:11 +0200 Original-Received: from localhost ([::1]:35820 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kVa7a-000826-93 for geb-bug-gnu-emacs@m.gmane-mx.org; Thu, 22 Oct 2020 08:55:10 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:53512) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kVa7S-00081n-SS for bug-gnu-emacs@gnu.org; Thu, 22 Oct 2020 08:55:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:40202) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kVa7S-0007hB-Iw for bug-gnu-emacs@gnu.org; Thu, 22 Oct 2020 08:55:02 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1kVa7S-0006xZ-Hg for bug-gnu-emacs@gnu.org; Thu, 22 Oct 2020 08:55:02 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Thu, 22 Oct 2020 12:55:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 44120 X-GNU-PR-Package: emacs Original-Received: via spool by 44120-submit@debbugs.gnu.org id=B44120.160337126726669 (code B ref 44120); Thu, 22 Oct 2020 12:55:02 +0000 Original-Received: (at 44120) by debbugs.gnu.org; 22 Oct 2020 12:54:27 +0000 Original-Received: from localhost ([127.0.0.1]:51742 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1kVa6t-0006w5-6c for submit@debbugs.gnu.org; Thu, 22 Oct 2020 08:54:27 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:53232) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1kVa6s-0006vr-0X for 44120@debbugs.gnu.org; Thu, 22 Oct 2020 08:54:26 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:42830) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kVa6j-0007dE-04; Thu, 22 Oct 2020 08:54:20 -0400 Original-Received: from [176.228.60.248] (port=4704 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1kVa6h-0000T4-Of; Thu, 22 Oct 2020 08:54:16 -0400 In-Reply-To: <20201021200842.GB47992@breton.holly.idiocy.org> (message from Alan Third on Wed, 21 Oct 2020 21:08:42 +0100) 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:191260 Archived-At: > Date: Wed, 21 Oct 2020 21:08:42 +0100 > From: Alan Third > Cc: 44120@debbugs.gnu.org > > >From image.c: > > /* From gif89a spec: 1 = "keep in place", 2 = "restore > to background". Treat any other value like 2. */ > > >From the gif89a spec: > > iv) Disposal Method - Indicates the way in which the graphic is to > be treated after being displayed. > > Values : 0 - No disposal specified. The decoder is > not required to take any action. > 1 - Do not dispose. The graphic is to be left > in place. > 2 - Restore to background color. The area used by the > graphic must be restored to the background color. > 3 - Restore to previous. The decoder is required to > restore the area overwritten by the graphic with > what was there prior to rendering the graphic. > 4-7 - To be defined. > > That gif uses a disposal value of 3 quite a lot. > > It looks like when a block is updated with a disposal value of 3 we > should hang onto the previous contents and then restore them in, I > guess, the next frame. FTR, the image renders correctly on MS-Windows when w32-use-native-image-API is non-nil, so this indeed seems like a problem with our GIF code.