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: Sun, 7 Jun 2020 11:13:01 +0200 Message-ID: <5AEB442C-5592-46E4-BC38-185BA9D2D956@acm.org> 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> <83r1us8kw6.fsf@gnu.org> <020DE875-14A8-457A-9AE4-AA0925DB8997@acm.org> <83img48ffx.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="7922"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 41544@debbugs.gnu.org To: Drew Adams Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Sun Jun 07 11:14:10 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 1jhrNZ-0001yX-2D for geb-bug-gnu-emacs@m.gmane-mx.org; Sun, 07 Jun 2020 11:14:09 +0200 Original-Received: from localhost ([::1]:48340 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jhrNX-0001Kv-Vu for geb-bug-gnu-emacs@m.gmane-mx.org; Sun, 07 Jun 2020 05:14:08 -0400 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:36320) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jhrNS-0001Kn-5F for bug-gnu-emacs@gnu.org; Sun, 07 Jun 2020 05:14:02 -0400 Original-Received: from debbugs.gnu.org ([209.51.188.43]:41755) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jhrNR-0002PN-SY for bug-gnu-emacs@gnu.org; Sun, 07 Jun 2020 05:14:01 -0400 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1jhrNR-0003rM-NG for bug-gnu-emacs@gnu.org; Sun, 07 Jun 2020 05:14:01 -0400 X-Loop: help-debbugs@gnu.org Resent-From: Mattias =?UTF-8?Q?Engdeg=C3=A5rd?= Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Sun, 07 Jun 2020 09:14:01 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 41544 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: patch Original-Received: via spool by 41544-submit@debbugs.gnu.org id=B41544.159152120914776 (code B ref 41544); Sun, 07 Jun 2020 09:14:01 +0000 Original-Received: (at 41544) by debbugs.gnu.org; 7 Jun 2020 09:13:29 +0000 Original-Received: from localhost ([127.0.0.1]:53301 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jhrMi-0003py-0x for submit@debbugs.gnu.org; Sun, 07 Jun 2020 05:13:29 -0400 Original-Received: from mail1452c50.megamailservers.eu ([91.136.14.52]:55370 helo=mail266c50.megamailservers.eu) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jhrMe-0003pe-KG for 41544@debbugs.gnu.org; Sun, 07 Jun 2020 05:13:14 -0400 X-Authenticated-User: mattiase@bredband.net DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=megamailservers.eu; s=maildub; t=1591521185; bh=ad0x7GweSYEUi4Vg+4WmH0UGicKq4vEERx2Xbjf9UbQ=; h=Subject:From:In-Reply-To:Date:Cc:References:To:From; b=gTXE1eHV+fs+0L60t83PoHMepBTdcuMsgeWcas1JmzJiTL/xRI5NKiho31yctuxvh yYPWL59R+eGQLnvSTZNcvf+0PhF+MfkbmTp5Y6UG3VqJ+ghQEPnDyINk+HE7emp7r/ Ki3pf+e4J+h95+fQ55yKaozvnNWJRjf6HONcwa7E= 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 mail266c50.megamailservers.eu (8.14.9/8.13.1) with ESMTP id 0579D1x6012431; Sun, 7 Jun 2020 09:13:04 +0000 X-Priority: 3 In-Reply-To: X-Mailer: Apple Mail (2.3445.104.14) X-CTCH-RefID: str=0001.0A782F23.5EDCAF25.0023: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=A5MSwJeG c=1 sm=1 tr=0 a=klNLuyVZdLUgl+K5Uafb2A==:117 a=klNLuyVZdLUgl+K5Uafb2A==:17 a=kj9zAlcOel0A:10 a=M51BFTxLslgA:10 a=yPCof4ZbAAAA:8 a=iLj94LE5IQj3-QTxvVkA:9 a=CjuIK1q_8ugA:10 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:181657 Archived-At: 6 juni 2020 kl. 20.15 skrev Drew Adams : > +(defun color-dark-p (rgb) > + "Whether RGB is more readable against white than black. > +RGB is a 3-element list (R G B), each component in the range [0,1]." > The predicate name suggests it's about testing a > color (via RGB) to determine whether it's dark or > light. >=20 > The doc string suggests it's specifically about > the readability of _foreground_ text that is of > that color - specifically whether it's more > readable against a white than a black background. Thank you, this actually raises a good point. The predicate should work with the argument both as a foreground and as = a background colour, for selecting a black or white contrasting colour. = The assumption is that the same predicate can be used for both, which = may be wrong, but absent evidence to the contrary, I think it is a = reasonable one to make. If you are in doubt, see if you can come up with a colour for which it = does not hold. For example, if you find a rare shade of beige that when = used for text looks better against a white background, but when used as = a background prefers black text. I have yet to do so, much less been = able to articulate it formally as an algorithm. I agree that this could be stated more explicitly in the doc string.