74 lines
3.4 KiB
C
74 lines
3.4 KiB
C
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/*-*- 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 "libc/macros.h"
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#include "libc/mem/mem.h"
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#include "libc/str/str.h"
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#include "libc/sysv/errfuns.h"
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#include "libc/time/time.h"
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#include "libc/x/x.h"
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#include "tool/viz/lib/convolution.h"
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#include "tool/viz/lib/graphic.h"
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/**
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* Enhances image detail.
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* @see https://en.wikipedia.org/wiki/Kernel_(image_processing)
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*/
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long unsharp(long cn, long yw, long xw, unsigned char img[cn][yw][xw], long yn,
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long xn) {
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long rc, c, y, x;
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unsigned *iy, *ix;
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short(*t)[3][xn] = xmemalign(64, sizeof(short) * xn * 3);
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iy = convoindex(2, yn, 2);
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ix = convoindex(2, xn, 2);
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if (t && ix && iy) {
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iy += 2;
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ix += 2;
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for (c = 0; c < 3; ++c) {
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for (y = 0; y < yn + 3; ++y) {
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if (y >= 3) {
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for (x = 0; x < xn; ++x) {
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img[c][y - 3][x] = MIN(255, MAX(0, (*t)[y % 3][x]));
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}
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memset((*t)[y % 3], 0, sizeof(short) * xn);
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}
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if (y < yn) {
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for (x = 0; x < xn; ++x) {
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(*t)[y % 3][x] = CONVOLVE5X5(/* clang-format off */
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7, (-1 / 256.), img[c],
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1, 4, 6, 4, 1,
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4, 16, 24, 16, 4,
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6, 24,-476, 24, 6,
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4, 16, 24, 16, 4,
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1, 4, 6, 4, 1
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/* clang-format on */);
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}
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}
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}
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}
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rc = 0;
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} else {
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rc = enomem();
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}
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free(t);
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if (ix) free(ix - 2);
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if (iy) free(iy - 2);
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return rc;
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}
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