120 lines
4.6 KiB
C
120 lines
4.6 KiB
C
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
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│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi│
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╞══════════════════════════════════════════════════════════════════════════════╡
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│ Copyright 2020 Justine Alexandra Roberts Tunney │
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│ │
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│ This program is free software; you can redistribute it and/or modify │
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│ it under the terms of the GNU General Public License as published by │
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│ the Free Software Foundation; version 2 of the License. │
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│ │
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│ This program is distributed in the hope that it will be useful, but │
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│ WITHOUT ANY WARRANTY; without even the implied warranty of │
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│ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU │
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│ General Public License for more details. │
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│ │
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│ You should have received a copy of the GNU General Public License │
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│ along with this program; if not, write to the Free Software │
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│ Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA │
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│ 02110-1301 USA │
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╚─────────────────────────────────────────────────────────────────────────────*/
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#include "dsp/core/core.h"
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#include "dsp/tty/quant.h"
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#include "libc/assert.h"
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#include "libc/bits/initializer.internal.h"
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#include "libc/limits.h"
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#include "libc/log/log.h"
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#include "libc/macros.h"
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#include "libc/math.h"
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#include "libc/str/str.h"
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#define CUTOFF_VALUE 200
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#define DIST(X, Y) ((X) - (Y))
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#define SQR(X) ((X) * (X))
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#define SUM(X, Y, Z) ((X) + (Y) + (Z))
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const uint8_t kXtermCube[6] = {0, 0137, 0207, 0257, 0327, 0377};
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struct TtyRgb g_ansi2rgb_[256];
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double g_xterm256_gamma;
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struct TtyRgb tty2rgb_(struct TtyRgb rgbxt) {
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return g_ansi2rgb_[rgbxt.xt];
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}
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__m128 tty2rgbf_(struct TtyRgb rgbxt) {
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rgbxt = g_ansi2rgb_[rgbxt.xt];
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return (__m128){(int)rgbxt.r, (int)rgbxt.g, (int)rgbxt.b} / 255;
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}
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static int rgb2xterm256_(int r, int g, int b) {
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int cerr, gerr, ir, ig, ib, gray, grai, cr, cg, cb, gv;
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gray = round(r * .299 + g * .587 + b * .114);
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grai = gray > 238 ? 23 : (gray - 3) / 10;
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ir = r < 48 ? 0 : r < 115 ? 1 : (r - 35) / 40;
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ig = g < 48 ? 0 : g < 115 ? 1 : (g - 35) / 40;
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ib = b < 48 ? 0 : b < 115 ? 1 : (b - 35) / 40;
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cr = kXtermCube[ir];
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cg = kXtermCube[ig];
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cb = kXtermCube[ib];
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gv = 8 + 10 * grai;
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cerr = SQR(DIST(cr, r)) + SQR(DIST(cg, g)) + SQR(DIST(cb, b));
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gerr = SQR(DIST(gv, r)) + SQR(DIST(gv, g)) + SQR(DIST(gv, b));
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if (cerr <= gerr) {
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return 16 + 36 * ir + 6 * ig + ib;
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} else {
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return 232 + grai;
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}
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}
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/**
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* Quantizes RGB to ANSI w/ euclidean distance in 3D color space.
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*/
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struct TtyRgb rgb2ansi_(int r, int g, int b) {
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uint32_t d, least;
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size_t c, best, min, max;
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r = MAX(MIN(r, 255), 0);
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g = MAX(MIN(g, 255), 0);
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b = MAX(MIN(b, 255), 0);
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min = ttyquant()->min;
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max = ttyquant()->max;
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if (min == 16 && max == 256) {
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return (struct TtyRgb){r, g, b, rgb2xterm256_(r, g, b)};
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} else {
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least = UINT32_MAX;
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best = 0;
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for (c = min; c < max; c++) {
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d = SUM(SQR(DIST(g_ansi2rgb_[c].r, r)), SQR(DIST(g_ansi2rgb_[c].g, g)),
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SQR(DIST(g_ansi2rgb_[c].b, b)));
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if (d < least) {
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least = d;
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best = c;
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}
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}
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return (struct TtyRgb){r, g, b, best};
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}
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}
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static int uncube(int x) {
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return x < 48 ? 0 : x < 115 ? 1 : (x - 35) / 40;
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}
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static textstartup void rgb2ansi_init(void) {
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uint8_t c, y;
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uint32_t i, j;
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memcpy(g_ansi2rgb_, &kCgaPalette, sizeof(kCgaPalette));
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for (i = 16; i < 232; ++i) {
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g_ansi2rgb_[i].r = kXtermCube[((i - 020) / 044) % 06];
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g_ansi2rgb_[i].g = kXtermCube[((i - 020) / 06) % 06];
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g_ansi2rgb_[i].b = kXtermCube[(i - 020) % 06];
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g_ansi2rgb_[i].xt = i;
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}
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for (i = 232, c = 8; i < 256; i++, c += 10) {
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g_ansi2rgb_[i].r = c;
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g_ansi2rgb_[i].g = c;
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g_ansi2rgb_[i].b = c;
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g_ansi2rgb_[i].xt = i;
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}
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}
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const void *const rgb2ansi_init_ctor[] initarray = {rgb2ansi_init};
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