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.devel Subject: Re: How to debug emacs repaint problems? Date: Sun, 15 Oct 2023 08:24:39 +0300 Message-ID: <83edhwqwyx.fsf@gnu.org> References: <87fs2duld0.fsf@tanaka.verona.se> <83jzrpqam9.fsf@gnu.org> <871qdxugud.fsf@tanaka.verona.se> <878r85t1dk.fsf@tanaka.verona.se> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="19723"; mail-complaints-to="usenet@ciao.gmane.io" Cc: emacs-devel@gnu.org To: joakim@verona.se Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Sun Oct 15 07:25:46 2023 Return-path: Envelope-to: ged-emacs-devel@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 1qrtdK-0004vI-7G for ged-emacs-devel@m.gmane-mx.org; Sun, 15 Oct 2023 07:25:46 +0200 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qrtcW-000146-Cw; Sun, 15 Oct 2023 01:24:56 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qrtcU-00013d-Lc for emacs-devel@gnu.org; Sun, 15 Oct 2023 01:24:54 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qrtcT-0004pz-4h; Sun, 15 Oct 2023 01:24:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=iGq4DzKaOot9B71DK089HzsB1PBJ70fadVU5rj5Vdlg=; b=lJo9wxrqpFSn 7wbEBiHLM0S9a/zr4UPG24fazow5aWttDiTqnP0HTcSrCe4hELzFqme9yvL/6fTl7hX9eFHuvPxVx gJXXoyzSsJ19hIz0AmjJMahEj+++J5hFMhrUsPzqnj/XPZTjSkJqz+AY79GUvfpUcnj5Aa/06TEsl FZtLtyuvdQ9vrVtg+As4sJ5LNmfN7JP2fdBqRJ5U4eBdGMdE1ID1eIUn8h8gdMlA2Q+MLwKioEQ2c jqMG1OWpqkyeK7ZumOuN41bcYdAjphPe16h/6DMDC1E/M5nW88yblUlzrZ207+VBohGe3zNXdx/HE lYhu4S7NhR6DBNpg0b/6qA==; In-Reply-To: <878r85t1dk.fsf@tanaka.verona.se> (joakim@verona.se) X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.devel:311470 Archived-At: > X-Spam-Status: No, score=-0.999 tagged_above=-999 required=6.2 > tests=[ALL_TRUSTED=-1, DC_PNG_UNO_LARGO=0.001] autolearn=disabled > From: joakim@verona.se > Cc: emacs-devel@gnu.org > Date: Sat, 14 Oct 2023 22:06:31 +0200 > > I managed to make a screenshot that shows the problem. In the image I > made an emacs window with some black text on red background. > > If I move the cursor just one line, you can see that 2 large regions > become blurred. Since I just moved the cursor one line down, its rather > confusing why these 2 seemingly unrelated regions should be redrawn. It is not Emacs that's doing that. When you move the cursor, Emacs redraws just two characters: the one where the cursor was before the move, and the one where it is after the move. It can also redraw a small part of the mode line: if the cursor is moved vertically, the part with the line number will be redrawn, and if you have column-number-mode enabled, the column number will be redrawn for any cursor movement. That's all. I think Po Lu explained why you see what you see. If disabling double-buffering doesn't help, I think the root cause is the VNC software you use, which must somehow decide which portions of the screen to redraw. Emacs is not the culprit here.