ti83-sdk/tool/tilem-src/emu/graycolor.c

91 lines
2.4 KiB
C

/*
* libtilemcore - Graphing calculator emulation library
*
* Copyright (C) 2010 Benjamin Moody
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, see
* <http://www.gnu.org/licenses/>.
*/
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdio.h>
#include <math.h>
#include "tilem.h"
dword* tilem_color_palette_new(int rlight, int glight, int blight,
int rdark, int gdark, int bdark,
double gamma)
{
dword* pal = tilem_new_atomic(dword, 256);
double r0, g0, b0, dr, dg, db;
double igamma = 1.0 / gamma;
double s = (1.0 / 255.0);
int r, g, b, i;
r0 = pow(rlight * s, gamma);
g0 = pow(glight * s, gamma);
b0 = pow(blight * s, gamma);
dr = (pow(rdark * s, gamma) - r0) * s;
dg = (pow(gdark * s, gamma) - g0) * s;
db = (pow(bdark * s, gamma) - b0) * s;
pal[0] = (rlight << 16) | (glight << 8) | blight;
for (i = 1; i < 255; i++) {
r = pow(r0 + i * dr, igamma) * 255.0 + 0.5;
if (r < 0) r = 0;
if (r > 255) r = 255;
g = pow(g0 + i * dg, igamma) * 255.0 + 0.5;
if (g < 0) g = 0;
if (g > 255) g = 255;
b = pow(b0 + i * db, igamma) * 255.0 + 0.5;
if (b < 0) b = 0;
if (b > 255) b = 255;
pal[i] = (r << 16) | (g << 8) | b;
}
pal[255] = (rdark << 16) | (gdark << 8) | bdark;
return pal;
}
byte* tilem_color_palette_new_packed(int rlight, int glight, int blight,
int rdark, int gdark, int bdark,
double gamma)
{
dword* palette;
byte* packed;
int i;
palette = tilem_color_palette_new(rlight, glight, blight,
rdark, gdark, bdark, gamma);
packed = tilem_new_atomic(byte, 256 * 3);
for (i = 0; i < 256; i++) {
packed[i * 3] = palette[i] >> 16;
packed[i * 3 + 1] = palette[i] >> 8;
packed[i * 3 + 2] = palette[i];
}
tilem_free(palette);
return packed;
}