1 /****************************************************************************
2 * Copyright 2018,2020 Thomas E. Dickey *
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9 * copies of the Software, and to permit persons to whom the Software is *
10 * furnished to do so, subject to the following conditions: *
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16 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF *
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27 ****************************************************************************/
28 /*
29 * $Id: parse_rgb.h,v 1.5 2020/02/02 23:34:34 tom Exp $
30 *
31 * Sample implementation of ncurses RGB extension from user_caps(5).
32 */
33 #ifndef PARSE_RBG_H_incl
34 #define PARSE_RBG_H_incl 1
35
36 #include <test.priv.h>
37
38 #if HAVE_TIGETSTR && USE_WIDEC_SUPPORT
39 static int
parse_rgb(int * r_max,int * g_max,int * b_max)40 parse_rgb(int *r_max, int *g_max, int *b_max)
41 {
42 int colors = tigetnum("colors");
43 int result = ERR;
44
45 *r_max = *g_max = *b_max = 0;
46
47 if (colors > 0) {
48 int max_bits;
49 int bits;
50 int pwr2;
51 int r = 0, g = 0, b = 0;
52 char *data;
53 char ch;
54
55 for (max_bits = 0, pwr2 = 1;
56 pwr2 < colors;
57 ++max_bits, pwr2 <<= 1) {
58 ;
59 }
60
61 if (tigetflag("RGB") > 0) {
62 result = OK;
63 r = g = b = (max_bits + 2) / 3;
64 } else if ((bits = tigetnum("RGB")) > 0) {
65 result = OK;
66 r = g = b = bits;
67 } else if ((data = tigetstr("RGB")) != ABSENT_STRING
68 && data != CANCELLED_STRING
69 && sscanf(data, "%d/%d/%d%c", &r, &g, &b, &ch) == 3) {
70 result = OK;
71 }
72
73 if ((r + g + b) < max_bits) {
74 result = ERR;
75 } else if (result == 0) {
76 if (r > max_bits) {
77 r = max_bits;
78 g = b = 0;
79 }
80 *r_max = r;
81 if (g > (max_bits -= r)) {
82 g = max_bits;
83 b = 0;
84 }
85 *g_max = g;
86 if (b > (max_bits -= g)) {
87 b = max_bits;
88 }
89 *b_max = b;
90 }
91 }
92 return result;
93 }
94 #else
95 #define parse_rgb(r,g,b) (ERR)
96 #endif
97
98 #endif /* PARSE_RBG_H_incl */
99