From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.devel Subject: Re: Display test suite Date: Thu, 07 Jul 2016 19:29:31 +0300 Message-ID: <83ziptjtsk.fsf@gnu.org> References: <83h9c1lbso.fsf@gnu.org> <577E79AA.2060208@gmail.com> Reply-To: Eli Zaretskii NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit X-Trace: ger.gmane.org 1467909066 13881 80.91.229.3 (7 Jul 2016 16:31:06 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 7 Jul 2016 16:31:06 +0000 (UTC) Cc: emacs-devel@gnu.org To: =?windows-1252?Q?Cl=E9ment?= Pit--Claudel Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Thu Jul 07 18:31:05 2016 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1bLCCe-0003fH-M0 for ged-emacs-devel@m.gmane.org; Thu, 07 Jul 2016 18:31:04 +0200 Original-Received: from localhost ([::1]:41111 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bLCCd-0002Ie-Qc for ged-emacs-devel@m.gmane.org; Thu, 07 Jul 2016 12:31:03 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:53613) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bLCBS-0002GN-EZ for emacs-devel@gnu.org; Thu, 07 Jul 2016 12:29:51 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bLCBN-0007Gn-FX for emacs-devel@gnu.org; Thu, 07 Jul 2016 12:29:49 -0400 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:57453) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bLCBN-0007GD-CV; Thu, 07 Jul 2016 12:29:45 -0400 Original-Received: from 84.94.185.246.cable.012.net.il ([84.94.185.246]:1919 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1bLCBL-0005jp-8m; Thu, 07 Jul 2016 12:29:43 -0400 In-reply-to: <577E79AA.2060208@gmail.com> (message from =?windows-1252?Q?C?= =?windows-1252?Q?l=E9ment?= Pit--Claudel on Thu, 7 Jul 2016 11:47:54 -0400) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 2001:4830:134:3::e X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 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.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:205349 Archived-At: > From: Clément Pit--Claudel > Date: Thu, 7 Jul 2016 11:47:54 -0400 > > Richard recently suggested giving Emacs the ability to take a screenshot of itself. Could we imagine using this to run regression tests of the display engine? Maybe I'm missing something, but I don't see how. A test suite needs to include the expected results for each test. Even if you include an image file for each test that shows what should be displayed, AFAIU the image will be specific to the display resolution, number of colors, dimensions, etc., so inappropriate for automatic comparison with the screenshot on the target machine. Am I right? Also, comparing images that could have a small number of pixels different in some corner is error-prone. IMO, a test suite for the display engine needs a way to describe precisely what's on the screen, in some language, and then compare those descriptions. > Of course, it could be hard to get screeenshots to looks exactly the same for everyone. Instead, we could have a makefile target that builds a large collection of these screenshots, and another one that rebuilds it and compares against a previously generated one. But then each time I start using a new machine, my reference point is reset to a newer date, and I lose the ability for comparing against older versions. Thanks.