/* $OpenBSD$ */
/*
* Copyright (c) 2008 Nicholas Marriott <nicholas.marriott@gmail.com>
* Copyright (c) 2016 Avi Halachmi <avihpit@yahoo.com>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
* IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
* OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "tmux.h"
static int
colour_dist_sq(int R, int G, int B, int r, int g, int b)
{
return ((R - r) * (R - r) + (G - g) * (G - g) + (B - b) * (B - b));
}
static int
colour_to_6cube(int v)
{
if (v < 48)
return (0);
if (v < 114)
return (1);
return ((v - 35) / 40);
}
/*
* Convert an RGB triplet to the xterm(1) 256 colour palette.
*
* xterm provides a 6x6x6 colour cube (16 - 231) and 24 greys (232 - 255). We
* map our RGB colour to the closest in the cube, also work out the closest
* grey, and use the nearest of the two.
*
* Note that the xterm has much lower resolution for darker colours (they are
* not evenly spread out), so our 6 levels are not evenly spread: 0x0, 0x5f
* (95), 0x87 (135), 0xaf (175), 0xd7 (215) and 0xff (255). Greys are more
* evenly spread (8, 18, 28 ... 238).
*/
int
colour_find_rgb(u_char r, u_char g, u_char b)
{
static const int q2c[6] = { 0x00, 0x5f, 0x87, 0xaf, 0xd7, 0xff };
int qr, qg, qb, cr, cg, cb, d, idx;
int grey_avg, grey_idx, grey;
/* Map RGB to 6x6x6 cube. */
qr = colour_to_6cube(r); cr = q2c[qr];
qg = colour_to_6cube(g); cg = q2c[qg];
qb = colour_to_6cube(b); cb = q2c[qb];
/* If we have hit the colour exactly, return early. */
if (cr == r && cg == g && cb == b)
return ((16 + (36 * qr) + (6 * qg) + qb) | COLOUR_FLAG_256);
/* Work out the closest grey (average of RGB). */
grey_avg = (r + g + b) / 3;
if (grey_avg > 238)
grey_idx = 23;
else
grey_idx = (grey_avg - 3) / 10;
grey = 8 + (10 * grey_idx);
/* Is grey or 6x6x6 colour closest? */
d = colour_dist_sq(cr, cg, cb, r, g, b);
if (colour_dist_sq(grey, grey, grey, r, g, b) < d)
idx = 232 + grey_idx;
else
idx = 16 + (36 * qr) + (6 * qg) + qb;
return (idx | COLOUR_FLAG_256);
}
/* Join RGB into a colour. */
int
colour_join_rgb(u_char r, u_char g, u_char b)
{
return ((((int)((r) & 0xff)) << 16) |
(((int)((g) & 0xff)) << 8) |
(((int)((b) & 0xff))) | COLOUR_FLAG_RGB);
}
/* Split colour into RGB. */
void
colour_split_rgb(int c, u_char *r, u_char *g, u_char *b)
{
*r = (c >> 16) & 0xff;
*g = (c >> 8) & 0xff;
*b = c & 0xff;
}
/* Convert colour to a string. */
const char *
colour_tostring(int c)
{
static char s[32];
u_char r, g, b;
if (c == -1)
return ("invalid");
if (c & COLOUR_FLAG_RGB) {
colour_split_rgb(c, &r, &g, &b);
xsnprintf(s, sizeof s, "#%02x%02x%02x", r, g, b);
return (s);
}
if (c & COLOUR_FLAG_256) {
xsnprintf(s, sizeof s, "colour%u", c & 0xff);
return (s);
}
switch (c) {
case 0:
return ("black");
case 1:
return ("red");
case 2:
return (&q