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/*
* Copyright 2012 Michael Drake <tlsa@netsurf-browser.org>
*
* This file is part of libnsfb, http://www.netsurf-browser.org/
* Licenced under the MIT License,
* http://www.opensource.org/licenses/mit-license.php
*/
/** \file
* Palette (implementation).
*/
#include <assert.h>
#include <stdbool.h>
#include <stdlib.h>
#include "palette.h"
/** Create an empty palette object. */
bool nsfb_palette_new(struct nsfb_palette_s **palette)
{
*palette = malloc(sizeof(struct nsfb_palette_s));
if (*palette == NULL) {
return false;
}
(*palette)->type = NSFB_PALETTE_EMPTY;
(*palette)->last = 0;
return true;
}
/** Free a palette object. */
void nsfb_palette_free(struct nsfb_palette_s *palette)
{
if (palette != NULL)
free(palette);
}
/** Generate libnsfb 8bpp default palette. */
void nsfb_palette_generate_nsfb_8bpp(struct nsfb_palette_s *palette)
{
int rloop, gloop, bloop;
int loop = 0;
uint8_t r, g, b;
/* Build a linear 6-8-5 levels RGB colour cube palette.
* This accounts for 240 colours */
#define RLIM 6
#define GLIM 8
#define BLIM 5
for (rloop = 0; rloop < RLIM; rloop++) {
for (gloop = 0; gloop < GLIM; gloop++) {
for (bloop = 0; bloop < BLIM; bloop++) {
r = ((rloop * 255 * 2) + RLIM - 1) /
(2 * (RLIM - 1));
g = ((gloop * 255 * 2) + GLIM - 1) /
(2 * (GLIM - 1));
b = ((bloop * 255 * 2) + BLIM - 1) /
(2 * (BLIM - 1));
palette->data[loop] = r | g << 8 | b << 16;
loop++;
}
}
}
#undef RLIM
#undef GLIM
#undef BLIM
/* Should have 240 colours set */
assert(loop == 240);
/* Fill index 240 to index 255 with grayscales */
/* Note: already have full black and full white from RGB cube */
for (; loop < 256; loop++) {
int ngray = loop - 240 + 1;
r = ngray * 15; /* 17*15 = 255 */
g = b = r;
palette->data[loop] = r | g << 8 | b << 16;
}
/* Set palette details */
palette->type = NSFB_PALETTE_NSFB_8BPP;
palette->last = 255;
}
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