From: Yuri Khan <yuri.v.khan@gmail.com>
To: "João Távora" <joaotavora@gmail.com>
Cc: Emacs developers <emacs-devel@gnu.org>,
Stefan Monnier <monnier@iro.umontreal.ca>,
Dmitry Gutov <dgutov@yandex.ru>
Subject: Re: VOTE: Changing completions-common-part face's default
Date: Thu, 7 Nov 2019 21:41:41 +0700 [thread overview]
Message-ID: <CAP_d_8UsoDnhS0ViCiTjAEP6801h0fK9Awqj1j53RMa7gzG48A@mail.gmail.com> (raw)
In-Reply-To: <CALDnm51HgBMSz=ad6GHm7_vVK8Q5aL4iyZeLH=gBQAYfnAJDtg@mail.gmail.com>
On Thu, 7 Nov 2019 at 20:53, João Távora <joaotavora@gmail.com> wrote:
> This points to a rule for finding the perfect good compromise:
> find the color equidistant to both black and white that passes
> both tests.
Because of the way contrast ratio is defined:
R = (L_lighter + 0.05) / (L_darker + 0.05)
if we require R(color, black) ≥ 4.5 and R(color, white) ≥ 4.5, we get:
(L(white) + 0.05) / (L(color) + 0.05) ≥ 4.5
1.05 / (L(color) + 0.05) ≥ 4.5
1.05 / 4.5 ≥ L(color) + 0.05
0.183333 ≥ L(color)
and:
(L(color) + 0.05) / (L(black) + 0.05) ≥ 4.5
(L(color) + 0.05) / 0.05 ≥ 4.5
L(color) + 0.05 ≥ 4.5 * 0.05 = 0.225
L(color) ≥ 0.175
So the set of colors that satisfy the 4.5:1 contrast criterion against
both white and black is a very thin surface of colors with relative
luminance between 0.175 and 0.183. Basically:
greens #008800 to #008a00
cyans #008282 to #008484
blues (somewhat tinted) #5e5eff to #6161ff
magentas #ce00ce to #d100d1
reds #eb0000 to #ee0000
yellows (rather, olives) #797900 to #7a7a00
grays #757575 to #767676
and various intermediates.
If you also want to account for the uncustomized 256-color xterm
palette, then I think it comes down to a single gray and maybe a
handful of cube colors. (Most non-black colors of that palette are
optimized for contrast against black background.)
However, the 4.5:1 threshold is tuned for readability of text on
background, not distinguishability of two text colors. For
distinguishability, maybe 3:1 or even lower would be enough.
next prev parent reply other threads:[~2019-11-07 14:41 UTC|newest]
Thread overview: 167+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-27 1:58 BIKESHED: completion faces Stefan Monnier
2019-10-27 11:34 ` João Távora
2019-10-27 21:45 ` Juri Linkov
2019-10-28 0:43 ` João Távora
2019-10-28 22:29 ` Juri Linkov
2019-10-28 23:31 ` João Távora
2019-10-29 21:53 ` Juri Linkov
2019-10-29 22:09 ` Dmitry Gutov
2019-10-29 22:57 ` João Távora
2019-10-29 1:12 ` Stefan Monnier
2019-10-29 21:58 ` Juri Linkov
2019-10-29 22:59 ` João Távora
2019-10-29 23:11 ` Dmitry Gutov
2019-10-30 1:49 ` Stefan Monnier
2019-11-03 21:53 ` Dmitry Gutov
2019-11-03 23:30 ` Stefan Monnier
2019-11-04 16:30 ` Dmitry Gutov
2019-11-04 18:31 ` Stefan Monnier
2019-11-04 22:52 ` João Távora
2019-11-04 23:25 ` Dmitry Gutov
2019-11-05 11:10 ` João Távora
2019-11-05 14:57 ` Dmitry Gutov
2019-11-05 15:44 ` Stefan Monnier
2019-11-05 16:30 ` João Távora
2019-11-05 21:27 ` Juri Linkov
2019-11-05 23:06 ` Stefan Monnier
2019-11-05 22:01 ` Dmitry Gutov
2019-11-06 0:18 ` Stefan Monnier
2019-11-06 8:24 ` Dmitry Gutov
2019-11-06 13:42 ` VOTE: Changing completions-common-part face's default Stefan Monnier
2019-11-06 17:16 ` João Távora
2019-11-06 17:26 ` Dmitry Gutov
2019-11-06 18:10 ` João Távora
2019-11-06 22:20 ` Dmitry Gutov
2019-11-06 22:42 ` João Távora
2019-11-06 22:57 ` Dmitry Gutov
2019-11-06 23:14 ` Stefan Monnier
2019-11-07 8:09 ` Dmitry Gutov
2019-11-07 10:27 ` João Távora
2019-11-07 13:27 ` Yuri Khan
2019-11-07 13:52 ` João Távora
2019-11-07 14:41 ` Yuri Khan [this message]
2019-11-07 14:57 ` João Távora
2019-11-07 16:04 ` Stefan Monnier
2019-11-07 16:09 ` João Távora
2019-11-07 14:43 ` Dmitry Gutov
2019-11-07 14:54 ` João Távora
2019-11-07 14:33 ` Dmitry Gutov
2019-11-07 14:44 ` João Távora
2019-11-07 14:58 ` Dmitry Gutov
2019-11-07 15:54 ` João Távora
2019-11-07 16:57 ` Drew Adams
2019-11-08 23:38 ` Dmitry Gutov
2019-11-09 0:24 ` João Távora
2019-11-09 1:53 ` Drew Adams
2019-11-09 21:57 ` Juri Linkov
2019-11-09 22:17 ` João Távora
2019-11-09 7:30 ` Eli Zaretskii
2019-11-09 11:42 ` João Távora
2019-11-09 12:04 ` Eli Zaretskii
2019-11-09 13:22 ` João Távora
2019-11-09 16:44 ` Drew Adams
2019-11-07 15:08 ` Stefan Monnier
2019-11-08 10:15 ` Dmitry Gutov
2019-11-08 19:19 ` Stefan Monnier
2019-11-08 19:43 ` Eli Zaretskii
2019-11-08 21:42 ` Stefan Monnier
2019-11-09 6:52 ` Eli Zaretskii
2019-11-09 15:25 ` Stefan Monnier
2019-11-09 15:52 ` Eli Zaretskii
2019-11-09 16:17 ` Stefan Monnier
2019-11-08 20:11 ` Dmitry Gutov
2019-11-08 22:57 ` João Távora
2019-11-06 23:12 ` Stefan Monnier
2019-11-05 16:31 ` BIKESHED: completion faces João Távora
2019-11-05 22:22 ` Dmitry Gutov
2019-11-05 23:11 ` João Távora
2019-11-06 8:18 ` Dmitry Gutov
2019-11-06 8:53 ` João Távora
2019-11-06 15:16 ` Dmitry Gutov
2019-11-06 15:56 ` João Távora
2019-11-06 10:25 ` João Távora
2019-11-06 15:11 ` Dmitry Gutov
2019-11-06 15:31 ` João Távora
2019-11-06 15:43 ` Dmitry Gutov
2019-11-06 15:48 ` João Távora
2019-11-06 16:01 ` Dmitry Gutov
2019-11-06 16:20 ` Eli Zaretskii
2019-11-06 21:36 ` Juri Linkov
2019-11-07 14:25 ` Eli Zaretskii
2019-11-07 22:40 ` Juri Linkov
2019-11-08 6:43 ` Eli Zaretskii
2019-11-06 16:12 ` Eli Zaretskii
2019-11-06 16:14 ` João Távora
2019-11-06 0:24 ` Stefan Monnier
2019-11-05 18:36 ` Stefan Monnier
2019-11-05 18:51 ` Eli Zaretskii
2019-11-05 19:16 ` João Távora
2019-11-05 19:23 ` Eli Zaretskii
2019-11-05 21:43 ` João Távora
2019-11-06 16:03 ` Eli Zaretskii
2019-11-06 16:26 ` João Távora
2019-11-06 18:07 ` Eli Zaretskii
2019-11-06 18:14 ` João Távora
2019-11-06 18:29 ` Eli Zaretskii
2019-11-06 18:48 ` João Távora
2019-11-06 20:51 ` Ergus
2019-11-07 14:08 ` Eli Zaretskii
2019-11-07 14:28 ` João Távora
2019-11-07 14:47 ` Eli Zaretskii
2019-11-07 15:00 ` João Távora
2019-11-07 15:40 ` Eli Zaretskii
2019-11-07 16:00 ` João Távora
2019-11-07 17:39 ` Eli Zaretskii
2019-11-07 17:53 ` João Távora
2019-11-07 18:16 ` Eli Zaretskii
2019-11-07 18:37 ` João Távora
2019-11-07 21:07 ` Eli Zaretskii
2019-11-07 21:43 ` João Távora
2019-11-08 6:35 ` Eli Zaretskii
2019-11-08 10:15 ` João Távora
2019-11-08 14:02 ` Eli Zaretskii
2019-11-08 15:09 ` João Távora
2019-11-08 15:33 ` Eli Zaretskii
2019-11-08 16:01 ` João Távora
2019-11-08 16:16 ` Eli Zaretskii
2019-11-08 16:27 ` João Távora
2019-11-08 17:05 ` Eli Zaretskii
2019-11-08 17:21 ` João Távora
2019-11-08 19:06 ` Eli Zaretskii
2019-11-08 22:49 ` João Távora
2019-11-09 6:57 ` Eli Zaretskii
2019-11-09 11:20 ` João Távora
2019-11-09 11:51 ` Eli Zaretskii
2019-11-09 12:14 ` João Távora
2019-11-09 12:19 ` Eli Zaretskii
2019-11-09 13:29 ` João Távora
2019-11-09 13:52 ` João Távora
2019-11-09 15:31 ` Eli Zaretskii
2019-11-09 18:51 ` João Távora
2019-11-10 9:18 ` Dmitry Gutov
2019-11-14 9:45 ` Eli Zaretskii
2019-11-14 10:40 ` Dmitry Gutov
2019-11-14 14:16 ` Eli Zaretskii
2019-11-14 14:19 ` João Távora
2019-11-14 14:42 ` Eli Zaretskii
2019-11-14 14:49 ` João Távora
2019-11-16 20:10 ` Juri Linkov
2019-11-16 23:40 ` João Távora
2019-11-17 17:27 ` Eli Zaretskii
2019-11-17 17:47 ` João Távora
2019-11-08 12:58 ` Stefan Monnier
2019-11-08 13:08 ` João Távora
2019-11-08 14:07 ` Eli Zaretskii
2019-11-06 20:34 ` Drew Adams
2019-11-06 20:42 ` Eli Zaretskii
2019-11-05 21:40 ` Dmitry Gutov
2019-11-05 23:02 ` Stefan Monnier
2019-11-05 18:54 ` João Távora
2019-11-05 19:07 ` Stefan Monnier
2019-11-05 21:39 ` Dmitry Gutov
2019-11-05 21:54 ` João Távora
2019-11-05 21:55 ` Dmitry Gutov
2019-11-05 21:54 ` Dmitry Gutov
2019-11-05 21:58 ` João Távora
2019-11-05 22:03 ` Dmitry Gutov
2019-11-05 22:07 ` João Távora
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