Epoch.

.gitignore

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+ff-notext

COPYING

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+ISC License
+
+Copyright (c) 2019, Adrian "vifino" Pistol
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

Makefile

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+CC ?= cc
+CFLAGS ?= -Os
+CPPFLAGS += -pedantic -Wall -Wextra #-fsanitize=address,undefined
+
+DESTDIR ?= /usr/local
+
+BINS=ff-notext
+all: $(BINS)
+
+ff-notext: ff-notext.c
+	$(CC) $(CPPFLAGS) $(CFLAGS) $(shell pkg-config --cflags --libs tesseract) $(LDFLAGS) -o ff-notext $^
+
+install: $(BINS)
+	install $(BINS) $(DESTDIR)/bin
+
+clean:
+	rm -f $(BINS) *.o

conversion.h

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+// Small library for color conversion.
+// All with alpha channel.
+// Uses doubles for conversion.
+// Not fast at all, but simple.
+#include <stdint.h>
+#include <math.h>
+
+// I know, I know, not standardized.
+// But painless fallback.
+#if defined(__linux__)
+#include <endian.h>
+#if __BYTE_ORDER != __BIG_ENDIAN
+#define DOCONVERT
+#endif
+#else
+#define DOCONVERT
+#include <arpa/inet.h>
+#define be32toh ntohl
+#define htobe32 htonl
+#define be16toh ntohs
+#define htobe16 htons
+#endif
+
+#ifndef FP
+#define FP double
+#endif
+
+#if FP == float
+#define POW powf
+#else
+#define POW pow
+#endif
+
+// BE uint16_t <-> NE uint16_t
+static inline void qbeush2ush(uint16_t* src, uint16_t* dst) {
+	dst[0] = be16toh(src[0]);
+	dst[1] = be16toh(src[1]);
+	dst[2] = be16toh(src[2]);
+	dst[3] = be16toh(src[3]);
+}
+static inline void qush2beush(uint16_t* src, uint16_t* dst) {
+	dst[0] = htobe16(src[0]);
+	dst[1] = htobe16(src[1]);
+	dst[2] = htobe16(src[2]);
+	dst[3] = htobe16(src[3]);
+}
+
+// uint16 <-> FP 0..1
+#define USH2FP(chan) (((FP) (chan)) / UINT16_MAX)
+#define FP2USH(chan) ((uint16_t) (chan * UINT16_MAX))
+
+static inline void qush2fp(uint16_t* src, FP* dst) {
+	dst[0] = USH2FP(src[0]);
+  dst[1] = USH2FP(src[1]);
+	dst[2] = USH2FP(src[2]);
+	dst[3] = USH2FP(src[3]);
+}
+static inline void qfp2ush(FP* src, uint16_t* dst) {
+	dst[0] = FP2USH(src[0]);
+  dst[1] = FP2USH(src[1]);
+	dst[2] = FP2USH(src[2]);
+	dst[3] = FP2USH(src[3]);
+}
+
+// SRGB <-> Linear RGB
+#define SRGB_THRES ((FP) 0.0031306684425217108)
+#define SRGB2RGB(s) ((s <= (SRGB_THRES * 12.92)) ? s / 12.92 : POW((s + 0.055) / 1.055, 2.4))
+#define RGB2SRGB(l) ((l <= SRGB_THRES) ? l * 12.92 : 1.055 * POW(l, 1.0/2.4) - 0.055)
+
+static inline void srgb2rgb(FP* src, FP* dst) {
+	dst[0] = SRGB2RGB(src[0]);
+  dst[1] = SRGB2RGB(src[1]);
+	dst[2] = SRGB2RGB(src[2]);
+	dst[3] = src[3]; // yep. very complicated.
+}
+static inline void rgb2srgb(FP* src, FP* dst) {
+	dst[0] = RGB2SRGB(src[0]);
+  dst[1] = RGB2SRGB(src[1]);
+	dst[2] = RGB2SRGB(src[2]);
+	dst[3] = src[3]; // yep. very complicated.
+}
+
+// Linear RGB <-> CIE XYZ
+#define MAT3MUL(s, v1, v2, v3) (s[0] * (FP)(v1) + s[1] * (FP)(v2) + s[2] * (FP)(v3))
+
+#define MAT3M3MUL(s, d, scale, r1m1, r1m2, r1m3, r2m1, r2m2, r2m3, r3m1, r3m2, r3m3) \
+	(d)[0] = MAT3MUL((s), r1m1, r1m2, r1m3) * (FP)(scale);								\
+	(d)[1] = MAT3MUL((s), r2m1, r2m2, r2m3) * (FP)(scale);								\
+	(d)[2] = MAT3MUL((s), r3m1, r3m2, r3m3) * (FP)(scale);
+
+static inline void rgb2xyz(FP* src, FP* dst) {
+	// table stolen from blind.
+	// seems to be a bit too bright?
+	MAT3M3MUL(src, dst, 1,
+						0.412457445582367576708548995157,
+						0.357575865245515878143578447634,
+						0.180437247826399665973085006954,
+						0.212673370378408277403536885686,
+						0.715151730491031756287156895269,
+						0.072174899130559869164791564344,
+						0.019333942761673460208893260415,
+						0.119191955081838593666354597644,
+						0.950302838552371742508739771438);
+
+	dst[3] = src[3]; // yep. very complicated.
+}
+
+static inline void xyz2rgb(FP* src, FP* dst) {
+	// table stolen from blind.
+	MAT3M3MUL(src, dst, 1,
+						3.240446254647737500675930277794,
+						-1.537134761820080575134284117667,
+						-0.498530193022728718155178739835,
+						-0.969266606244679751469561779231,
+						1.876011959788370209167851498933,
+						0.041556042214430065351304932619,
+						0.055643503564352832235773149705,
+						-0.204026179735960239147729566866,
+						1.057226567722703292062647051353);
+	dst[3] = src[3];
+}

ff-notext.c

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+// ┳━┓┳━┓  ┏┓┓┏━┓┏┓┓┳━┓┓ ┃┏┓┓
+// ┣━ ┣━ ━━┃┃┃┃ ┃ ┃ ┣━ ┏╋┛ ┃
+// ┇  ┇    ┇┗┛┛━┛ ┇ ┻━┛┇ ┗ ┇
+// ff-notext: censor text using tesseract
+// Usage: <farbfeld source> | ff-notext | <farbfeld sink>
+// made by vifino. ISC (C) vifino 2019
+
+#include <stdio.h>
+#include <string.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <arpa/inet.h>
+
+#include <tesseract/capi.h>
+
+#include "conversion.h"
+
+#define eprintf(...) fprintf(stderr, __VA_ARGS__)
+
+// IO helpers.
+static inline void chew(FILE* file, void* buffer, size_t bytes) {
+	if (!fread(buffer, bytes, 1, file)) {
+		eprintf("wanted more bytes, didn't get any?\n");
+		exit(1);
+	}
+}
+static inline void spew(FILE* file, void* buffer, size_t bytes) {
+	if (file)
+		if (!fwrite(buffer, bytes, 1, file)) {
+			eprintf("write failed.\n");
+			exit(1);
+		}
+}
+
+static void ffparse(FILE* food, FILE* out, uint32_t* w, uint32_t* h) {
+	char buf[8];
+	chew(food, buf, 8);
+	if (strncmp(buf, "farbfeld", 8) != 0) {
+		eprintf("file is not a farbfeld image?\n");
+		exit(1);
+	}
+	spew(out, buf, 8);
+
+	chew(food, buf, 8);
+	*w = ntohl(*(uint32_t*)buf);
+	*h = ntohl(*(uint32_t*)(buf + 4));
+	if (!w || !h) {
+		eprintf("image has zero dimension?\n");
+		exit(1);
+	}
+	spew(out, buf, 8);
+}
+
+int main() {
+	// initialize tesseract.
+	TessBaseAPI* tess = TessBaseAPICreate();
+	if (TessBaseAPIInit3(tess, NULL, "eng") != 0) {
+		eprintf("[ff-notext] Error initializing Tesseract.");
+		return 2;
+	}
+	//TessBaseAPISetVariable(tess, "tessedit_pageseg_mode", "11");
+	//TessBaseAPISetPageSegMode(tess, PSM_AUTO_ONLY);
+	TessBaseAPISetVariable(tess, "load_system_dawg", "false");
+	TessBaseAPISetVariable(tess, "load_freq_dawg", "false");
+	eprintf("[ff-notext] Initialized Tesseract %s\n", TessVersion());
+
+	// parse input image
+	uint32_t w, h;
+	ffparse(stdin, stdout, &w, &h);
+
+	uint16_t* frame = malloc(w * h * sizeof(uint16_t) * 4);
+	if (!frame) return 2;
+
+	uint8_t* rgba32 = malloc(w * h * 4);
+	if (!rgba32) return 2;
+
+	size_t x, y;
+	uint16_t buf[4] = {0};
+	for (y = 0; y < h; y++) {
+		for (x = 0; x < w; x++) {
+			// nom.
+			chew(stdin, buf, 8);
+			size_t off = (x + (y * w)) * 4;
+			frame[off + 0] = buf[0];
+			frame[off + 1] = buf[1];
+			frame[off + 2] = buf[2];
+			frame[off + 3] = buf[3];
+
+			if (buf[3]) { // only if alpha is set
+#ifdef DOCONVERT
+				qbeush2ush(buf, buf);
+#endif
+				rgba32[off + 0] = buf[0] / 256;
+				rgba32[off + 1] = buf[1] / 256;
+				rgba32[off + 2] = buf[2] / 256;
+				rgba32[off + 3] = buf[3] / 256;
+			} else {
+				rgba32[off + 0] = 0;
+				rgba32[off + 1] = 0;
+				rgba32[off + 2] = 0;
+				rgba32[off + 3] = 0;
+			}
+		}
+	}
+
+	// Look for text, kill it.
+	eprintf("[ff-notext] Setting image..\n");
+	TessBaseAPISetImage(tess, rgba32, w, h, 4, 4 * w);
+	//TessBaseAPISetImage2(tess, image);
+	if (TessBaseAPIGetSourceYResolution(tess) < 70) {
+		TessBaseAPISetSourceResolution(tess, 70);
+	}
+
+	eprintf("[ff-notext] Recognizing...\n");
+	if (TessBaseAPIRecognize(tess, NULL) != 0) {
+		eprintf("[ff-notext] error in tesseract recognition\n");
+		return 3;
+	}
+
+	eprintf("[ff-notext] Iterating over results...\n");
+	TessResultIterator* ri = TessBaseAPIGetIterator(tess);
+	TessPageIteratorLevel level = RIL_WORD;
+	if (ri != 0) {
+		do {
+			int sx, sy;
+		  int ex, ey;
+			TessPageIteratorBoundingBox(ri, level, &sx, &sy, &ex, &ey);
+			if (sx != 0 && sy != 0 && ex != w && ey != h)
+				for (y = sy; y <= ey; y++)
+					for (x = sx; x <= ex; x++) {
+						int off = (x + (y*w)) * 4;
+						frame[off + 0] = 0;
+						frame[off + 1] = 0;
+						frame[off + 2] = 0;
+						frame[off + 3] = 0;
+					}
+
+			char* word = TessResultIteratorGetUTF8Text(ri, level);
+			eprintf("[ff-notext] [(%u,%u),(%u,%u)}]: %s\n", sx, sy, ex, ey, word);
+			free(word);
+		} while (TessPageIteratorNext(ri, level));
+	}
+	free(rgba32);
+
+	// Write out.
+	spew(stdout, frame, w*h*sizeof(int16_t)*4);
+	free(frame);
+	return 0;
+}