1 /*
2 * libtilemcore - Graphing calculator emulation library
3 *
4 * Copyright (C) 2010 Benjamin Moody
5 *
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public License
8 * as published by the Free Software Foundation; either version 2.1 of
9 * the License, or (at your option) any later version.
10 *
11 * This library is distributed in the hope that it will be useful, but
12 * WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with this library; if not, see
18 * <http://www.gnu.org/licenses/>.
19 */
20
21 #ifdef HAVE_CONFIG_H
22 # include <config.h>
23 #endif
24
25 #include <stdio.h>
26 #include <math.h>
27 #include "tilem.h"
28
tilem_color_palette_new(int rlight,int glight,int blight,int rdark,int gdark,int bdark,double gamma)29 dword* tilem_color_palette_new(int rlight, int glight, int blight,
30 int rdark, int gdark, int bdark,
31 double gamma)
32 {
33 dword* pal = tilem_new_atomic(dword, 256);
34 double r0, g0, b0, dr, dg, db;
35 double igamma = 1.0 / gamma;
36 double s = (1.0 / 255.0);
37 int r, g, b, i;
38
39 r0 = pow(rlight * s, gamma);
40 g0 = pow(glight * s, gamma);
41 b0 = pow(blight * s, gamma);
42 dr = (pow(rdark * s, gamma) - r0) * s;
43 dg = (pow(gdark * s, gamma) - g0) * s;
44 db = (pow(bdark * s, gamma) - b0) * s;
45
46 pal[0] = (rlight << 16) | (glight << 8) | blight;
47
48 for (i = 1; i < 255; i++) {
49 r = pow(r0 + i * dr, igamma) * 255.0 + 0.5;
50 if (r < 0) r = 0;
51 if (r > 255) r = 255;
52
53 g = pow(g0 + i * dg, igamma) * 255.0 + 0.5;
54 if (g < 0) g = 0;
55 if (g > 255) g = 255;
56
57 b = pow(b0 + i * db, igamma) * 255.0 + 0.5;
58 if (b < 0) b = 0;
59 if (b > 255) b = 255;
60
61 pal[i] = (r << 16) | (g << 8) | b;
62 }
63
64 pal[255] = (rdark << 16) | (gdark << 8) | bdark;
65
66 return pal;
67 }
68
tilem_color_palette_new_packed(int rlight,int glight,int blight,int rdark,int gdark,int bdark,double gamma)69 byte* tilem_color_palette_new_packed(int rlight, int glight, int blight,
70 int rdark, int gdark, int bdark,
71 double gamma)
72 {
73 dword* palette;
74 byte* packed;
75 int i;
76
77 palette = tilem_color_palette_new(rlight, glight, blight,
78 rdark, gdark, bdark, gamma);
79
80 packed = tilem_new_atomic(byte, 256 * 3);
81 for (i = 0; i < 256; i++) {
82 packed[i * 3] = palette[i] >> 16;
83 packed[i * 3 + 1] = palette[i] >> 8;
84 packed[i * 3 + 2] = palette[i];
85 }
86
87 tilem_free(palette);
88
89 return packed;
90 }
91