tmux/colour.c

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/* $OpenBSD$ */
/*
* 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 "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 colors (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 & 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 ("green");
case 3:
return ("yellow");
case 4:
return ("blue");
case 5:
return ("magenta");
case 6:
return ("cyan");
case 7:
return ("white");
case 8:
return ("default");
case 90:
return ("brightblack");
case 91:
return ("brightred");
case 92:
return ("brightgreen");
case 93:
return ("brightyellow");
case 94:
return ("brightblue");
case 95:
return ("brightmagenta");
case 96:
return ("brightcyan");
case 97:
return ("brightwhite");
}
return (NULL);
}
/* Convert colour from string. */
int
colour_fromstring(const char *s)
{
const char *errstr;
const char *cp;
int n;
u_char r, g, b;
if (*s == '#' && strlen(s) == 7) {
for (cp = s + 1; isxdigit((u_char) *cp); cp++)
;
if (*cp != '\0')
return (-1);
n = sscanf(s + 1, "%2hhx%2hhx%2hhx", &r, &g, &b);
if (n != 3)
return (-1);
return (colour_join_rgb(r, g, b));
}
if (strncasecmp(s, "colour", (sizeof "colour") - 1) == 0) {
n = strtonum(s + (sizeof "colour") - 1, 0, 255, &errstr);
if (errstr != NULL)
return (-1);
return (n | COLOUR_FLAG_256);
}
if (strcasecmp(s, "black") == 0 || strcmp(s, "0") == 0)
return (0);
if (strcasecmp(s, "red") == 0 || strcmp(s, "1") == 0)
return (1);
if (strcasecmp(s, "green") == 0 || strcmp(s, "2") == 0)
return (2);
if (strcasecmp(s, "yellow") == 0 || strcmp(s, "3") == 0)
return (3);
if (strcasecmp(s, "blue") == 0 || strcmp(s, "4") == 0)
return (4);
if (strcasecmp(s, "magenta") == 0 || strcmp(s, "5") == 0)
return (5);
if (strcasecmp(s, "cyan") == 0 || strcmp(s, "6") == 0)
return (6);
if (strcasecmp(s, "white") == 0 || strcmp(s, "7") == 0)
return (7);
if (strcasecmp(s, "default") == 0 || strcmp(s, "8") == 0)
return (8);
if (strcasecmp(s, "brightblack") == 0 || strcmp(s, "90") == 0)
return (90);
if (strcasecmp(s, "brightred") == 0 || strcmp(s, "91") == 0)
return (91);
if (strcasecmp(s, "brightgreen") == 0 || strcmp(s, "92") == 0)
return (92);
if (strcasecmp(s, "brightyellow") == 0 || strcmp(s, "93") == 0)
return (93);
if (strcasecmp(s, "brightblue") == 0 || strcmp(s, "94") == 0)
return (94);
if (strcasecmp(s, "brightmagenta") == 0 || strcmp(s, "95") == 0)
return (95);
if (strcasecmp(s, "brightcyan") == 0 || strcmp(s, "96") == 0)
return (96);
if (strcasecmp(s, "brightwhite") == 0 || strcmp(s, "97") == 0)
return (97);
return (-1);
}
/* Convert 256 colour palette to 16. */
u_char
colour_256to16(u_char c)
{
static const u_char table[256] = {
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15,
0, 4, 4, 4, 12, 12, 2, 6, 4, 4, 12, 12, 2, 2, 6, 4,
12, 12, 2, 2, 2, 6, 12, 12, 10, 10, 10, 10, 14, 12, 10, 10,
10, 10, 10, 14, 1, 5, 4, 4, 12, 12, 3, 8, 4, 4, 12, 12,
2, 2, 6, 4, 12, 12, 2, 2, 2, 6, 12, 12, 10, 10, 10, 10,
14, 12, 10, 10, 10, 10, 10, 14, 1, 1, 5, 4, 12, 12, 1, 1,
5, 4, 12, 12, 3, 3, 8, 4, 12, 12, 2, 2, 2, 6, 12, 12,
10, 10, 10, 10, 14, 12, 10, 10, 10, 10, 10, 14, 1, 1, 1, 5,
12, 12, 1, 1, 1, 5, 12, 12, 1, 1, 1, 5, 12, 12, 3, 3,
3, 7, 12, 12, 10, 10, 10, 10, 14, 12, 10, 10, 10, 10, 10, 14,
9, 9, 9, 9, 13, 12, 9, 9, 9, 9, 13, 12, 9, 9, 9, 9,
13, 12, 9, 9, 9, 9, 13, 12, 11, 11, 11, 11, 7, 12, 10, 10,
10, 10, 10, 14, 9, 9, 9, 9, 9, 13, 9, 9, 9, 9, 9, 13,
9, 9, 9, 9, 9, 13, 9, 9, 9, 9, 9, 13, 9, 9, 9, 9,
9, 13, 11, 11, 11, 11, 11, 15, 0, 0, 0, 0, 0, 0, 8, 8,
8, 8, 8, 8, 7, 7, 7, 7, 7, 7, 15, 15, 15, 15, 15, 15
};
return (table[c]);
}