From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.ciao.gmane.io!not-for-mail From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Newsgroups: gmane.emacs.bugs Subject: bug#41544: 26.3; Possible incorrect results from color-distance Date: Sat, 6 Jun 2020 12:59:53 +0200 Message-ID: References: <5C4A633D-8222-4439-BE37-9B8674F1DA6D@acm.org> <87r1v2aat3.fsf@tromey.com> <9902865C-01B4-4E50-A433-DBC8B8311234@acm.org> <83tuzueogo.fsf@gnu.org> <6272275C-560C-4437-90F1-2A8294D27019@acm.org> <83o8q2elja.fsf@gnu.org> <83mu5mel4o.fsf@gnu.org> <77F1DDD3-A69F-40ED-902D-74986D5E6596@acm.org> <83y2p5cumz.fsf@gnu.org> <83blm0cjlz.fsf@gnu.org> <83367ccf8w.fsf@gnu.org> <624D7FB8-A836-4A7E-8895-47E867214504@acm.org> <83o8pyc4bq.fsf@gnu.org> <55D73CA5-1EFB-4B0A-8F8B-FDA1D39F51BF@acm.org> <835zc5bsut.fsf@gnu.org> <3BBCFDD4-C14D-4628-91CB-2A0456A96FC7@acm.org> <838sh0abzz.fsf@gnu.org> Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.14\)) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Injection-Info: ciao.gmane.io; posting-host="ciao.gmane.io:159.69.161.202"; logging-data="36805"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 41544@debbugs.gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sat Jun 06 13:01:14 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 1jhWZe-0009Uk-Hr for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 06 Jun 2020 13:01:14 +0200 Original-Received: from localhost ([::1]:45656 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jhWZd-0004HU-AG for geb-bug-gnu-emacs@m.gmane-mx.org; Sat, 06 Jun 2020 07:01:13 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:56544) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jhWZT-0004GK-8P for bug-gnu-emacs@gnu.org; Sat, 06 Jun 2020 07:01:03 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:39329) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jhWZS-0002k6-6Y for bug-gnu-emacs@gnu.org; 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Sat, 06 Jun 2020 07:00:05 -0400 X-Authenticated-User: mattiase@bredband.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megamailservers.eu; s=maildub; t=1591441197; bh=3396mviELq+yOhmgZNGLlG7HXvBLyK1Pi+qhuA0uLP0=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From; b=RuLbfhUPbaGVBBIyROSpVvHFYUIpzAdiBvrI/x/VjrdSzJNpCEzghdRyTgLgefGiM ahgSly/5YGjihLqI2BL2p5hPFJM/O+AqzEdkWPvv5Haxn1B2fuK8So69TjZK3K6kUz mtM7v4fxESf/mxZe77DqSLnkL3SqVEg5z7vn0j4I= Feedback-ID: mattiase@acm.or Original-Received: from stanniol.lan (c-4e4ae655.032-75-73746f71.bbcust.telenor.se [85.230.74.78]) (authenticated bits=0) by mail264c50.megamailservers.eu (8.14.9/8.13.1) with ESMTP id 056AxsUb014456; Sat, 6 Jun 2020 10:59:56 +0000 In-Reply-To: <838sh0abzz.fsf@gnu.org> X-Mailer: Apple Mail (2.3445.104.14) X-CTCH-RefID: str=0001.0A782F27.5EDB76CD.0044:SCFSTAT68638221, ss=1, re=-4.000, recu=0.000, reip=0.000, cl=1, cld=1, fgs=0 X-CTCH-VOD: Unknown X-CTCH-Spam: Unknown X-CTCH-Score: -4.000 X-CTCH-Flags: 0 X-CTCH-ScoreCust: 0.000 X-CSC: 0 X-CHA: v=2.3 cv=PPNxBsiC c=1 sm=1 tr=0 a=klNLuyVZdLUgl+K5Uafb2A==:117 a=klNLuyVZdLUgl+K5Uafb2A==:17 a=kj9zAlcOel0A:10 a=M51BFTxLslgA:10 a=mDV3o1hIAAAA:8 a=Ecc4TiwEbbgJAD0glIkA:9 a=CjuIK1q_8ugA:10 a=_FVE-zBwftR9WsbkzFJk:22 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:181606 Archived-At: [I've left Tom and Simon out of the CC list to spare them the noise.] 6 juni 2020 kl. 09.29 skrev Eli Zaretskii : > That in itself is not bad, IMO. When I said "in practice", I meant > practical problems this causes, and that inevitably involves some > callers of that function (and the callers of those callers) that > suffer problems which show on display or cause incorrect decisions to > be made in specific Lisp applications. What you presented are > theoretical difficulties that IMO don't yet justify any significant > changes on this level, not by themselves. Thank you all the same, but I'd like to fix this bug nevertheless. It is = clearly a bug, and I'm one of those writing code calling color-values = and thus being affected by it. Of course, if you can show some negative = consequence of the suggested fix, then some alternative has to be = considered. Instead of replying point-for-point, which can go on forever, let's try = to break the stalemate; we are clearly talking past one another. I'm = trying to understand your assumptions, and hope that you will do me the = same courtesy. The values returned from color-values are scaled to a maximum of 65535 = for all Emacs displays (except NS). Just because a TTY does not have a = 'white' colour with RGB values (65535 65535 65535) does not mean that = the scale is somehow different. In the case of TERM=3Dxterm-color, the brightest colour (confusingly = named "white") is (58853 58853 58853). This doesn't mean that 58853 is = the maximum colour component value; it just means that the brightest = colour is not pure white but something like a 90% grey, ie (0.9 0.9 0.9) = in 1-normalised RGB notation. The method of using (color-values "#ffffffffffff") was a clever trick = for obtaining the scale factor without having to know exactly what the = maximum was for that frame, since parts of Emacs had different ideas of = what range to actually use: it was common for some time to convert from = 8 to 16 bit/channel by shifting 8 bits to the left. I've read through = bug#25890 and bug#24273, as well as poured over the change history, and = it seems very clear where this came from. However, the back-end code appears much more robust and regular now, and = the code can be simplified, as well as avoiding the irregularities = occurring with TTYs lacking a pure white colour. Surely there is no harm = in that?