linux-kernel - [PATCH 4/6] vt: change 256-color palette to match all(?) modern terminals

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Date:   Wed, 18 Jul 2018 05:03:25 +0200
From:   Adam Borowski <kilobyte@...band.pl>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jiri Slaby <jslaby@...e.com>, linux-console@...r.kernel.org,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        linux-fbdev@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Adam Borowski <kilobyte@...band.pl>
Subject: [PATCH 4/6] vt: change 256-color palette to match all(?) modern terminals

Turns out that osso-xterm which I based upon uses something a lot different
from apparently any other terminal -- they all use identical shades, much
brighter than what I copied:

    Old: 00 2a 55 7f aa d4
    New: 00 5f 87 af d7 ff

This did hardly matter as we immediately shoehorn the colors into only 16
values, but recently 24-bit codes turned from an oddity to something
widespread, thus it's better to handle 256 vs 24-bit consistently.

Signed-off-by: Adam Borowski <kilobyte@...band.pl>
---
 drivers/tty/vt/vt.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 4096093c8cd2..8c61caafdf3c 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -1545,9 +1545,12 @@ static void rgb_from_256(int i, struct rgb *c)
 		c->g = i&2 ? 0xff : 0x55;
 		c->b = i&4 ? 0xff : 0x55;
 	} else if (i < 232) {   /* 6x6x6 colour cube. */
-		c->r = (i - 16) / 36 * 85 / 2;
-		c->g = (i - 16) / 6 % 6 * 85 / 2;
-		c->b = (i - 16) % 6 * 85 / 2;
+		int r = (i - 16) / 36;
+		int g = (i - 16) / 6 % 6;
+		int b = (i - 16) % 6;
+		c->r = r ? r * 0x28 + 0x37 : 0;
+		c->g = g ? g * 0x28 + 0x37 : 0;
+		c->b = b ? b * 0x28 + 0x37 : 0;
 	} else                  /* Grayscale ramp. */
 		c->r = c->g = c->b = i * 10 - 2312;
 }
-- 
2.18.0