Factor out png.h

4 files changed, 121 insertions, 92 deletions

diff --git a/bin/Makefile b/bin/Makefile
index d68d1cc5..6b6452aa 100644
--- a/bin/Makefile
+++ b/bin/Makefile
@@ -54,6 +54,8 @@ scheme.h: scheme
 open pbcopy pbpaste: pbd
 	ln -f pbd $@
 
+psf2png.o scheme.o: png.h
+
 scheme.png: scheme
 	./scheme -t -g > scheme.png
 
diff --git a/bin/png.h b/bin/png.h
new file mode 100644
index 00000000..63c80342
--- /dev/null
+++ b/bin/png.h
@@ -0,0 +1,92 @@
+/* Copyright (C) 2018  June McEnroe <june@causal.agency>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <arpa/inet.h>
+#include <err.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sysexits.h>
+#include <zlib.h>
+
+enum {
+	PNGGrayscale,
+	PNGTruecolor = 2,
+	PNGIndexed,
+	PNGAlpha,
+};
+
+enum {
+	PNGNone,
+	PNGSub,
+	PNGUp,
+	PNGAverage,
+	PNGPaeth,
+};
+
+static uint32_t pngCRC;
+static inline void pngWrite(FILE *file, const void *ptr, size_t len) {
+	if (!fwrite(ptr, len, 1, file)) err(EX_IOERR, "pngWrite");
+	pngCRC = crc32(pngCRC, ptr, len);
+}
+static inline void pngInt32(FILE *file, uint32_t n) {
+	n = htonl(n);
+	pngWrite(file, &n, 4);
+}
+static inline void pngChunk(FILE *file, char type[static 4], uint32_t len) {
+	pngInt32(file, len);
+	pngCRC = crc32(0, Z_NULL, 0);
+	pngWrite(file, type, 4);
+}
+
+static inline void pngHead(
+	FILE *file, uint32_t width, uint32_t height, uint8_t depth, uint8_t color
+) {
+	pngWrite(file, "\x89PNG\r\n\x1A\n", 8);
+	pngChunk(file, "IHDR", 13);
+	pngInt32(file, width);
+	pngInt32(file, height);
+	pngWrite(file, &depth, 1);
+	pngWrite(file, &color, 1);
+	pngWrite(file, "\0\0\0", 3);
+	pngInt32(file, pngCRC);
+}
+
+static inline void pngPalette(FILE *file, const uint8_t *pal, uint32_t len) {
+	pngChunk(file, "PLTE", len);
+	pngWrite(file, pal, len);
+	pngInt32(file, pngCRC);
+}
+
+static inline void pngData(FILE *file, const uint8_t *data, uint32_t len) {
+	uLong zlen = compressBound(len);
+	uint8_t *zdata = malloc(zlen);
+	if (!zlen) err(EX_OSERR, "malloc");
+
+	int error = compress(zdata, &zlen, data, len);
+	if (error != Z_OK) errx(EX_SOFTWARE, "compress: %d", error);
+
+	pngChunk(file, "IDAT", zlen);
+	pngWrite(file, zdata, zlen);
+	pngInt32(file, pngCRC);
+
+	free(zdata);
+}
+
+static inline void pngTail(FILE *file) {
+	pngChunk(file, "IEND", 0);
+	pngInt32(file, pngCRC);
+}
diff --git a/bin/psf2png.c b/bin/psf2png.c
index 2ccf0580..c36238a0 100644
--- a/bin/psf2png.c
+++ b/bin/psf2png.c
@@ -14,7 +14,6 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <arpa/inet.h>
 #include <err.h>
 #include <stdint.h>
 #include <stdio.h>
@@ -22,23 +21,8 @@
 #include <string.h>
 #include <sysexits.h>
 #include <unistd.h>
-#include <zlib.h>
 
-static uint32_t crc;
-static void pngWrite(const void *ptr, size_t size) {
-	fwrite(ptr, size, 1, stdout);
-	if (ferror(stdout)) err(EX_IOERR, "(stdout)");
-	crc = crc32(crc, ptr, size);
-}
-static void pngInt(uint32_t host) {
-	uint32_t net = htonl(host);
-	pngWrite(&net, 4);
-}
-static void pngChunk(const char *type, uint32_t size) {
-	pngInt(size);
-	crc = crc32(0, Z_NULL, 0);
-	pngWrite(type, 4);
-}
+#include "png.h"
 
 int main(int argc, char *argv[]) {
 	uint32_t cols = 32;
@@ -91,26 +75,20 @@ int main(int argc, char *argv[]) {
 	}
 	fclose(file);
 
-	pngWrite("\x89PNG\r\n\x1A\n", 8);
-
 	uint32_t count = (str ? strlen(str) : header.glyph.len);
 	uint32_t width = header.glyph.width * cols;
 	uint32_t rows = (count + cols - 1) / cols;
 	uint32_t height = header.glyph.height * rows;
 
-	pngChunk("IHDR", 13);
-	pngInt(width);
-	pngInt(height);
-	pngWrite("\x08\x03\x00\x00\x00", 5);
-	pngInt(crc);
-
-	pngChunk("PLTE", 6);
-	pngWrite((uint8_t[]) { bg >> 16, bg >> 8, bg }, 3);
-	pngWrite((uint8_t[]) { fg >> 16, fg >> 8, fg }, 3);
-	pngInt(crc);
+	pngHead(stdout, width, height, 8, PNGIndexed);
+	uint8_t pal[] = {
+		bg >> 16, bg >> 8, bg,
+		fg >> 16, fg >> 8, fg,
+	};
+	pngPalette(stdout, pal, sizeof(pal));
 
 	uint8_t data[height][1 + width];
-	memset(data, 0, sizeof(data));
+	memset(data, PNGNone, sizeof(data));
 
 	for (uint32_t i = 0; i < count; ++i) {
 		uint32_t row = header.glyph.height * (i / cols);
@@ -124,15 +102,6 @@ int main(int argc, char *argv[]) {
 		}
 	}
 
-	uLong size = compressBound(sizeof(data));
-	uint8_t deflate[size];
-	int error = compress(deflate, &size, (Byte *)data, sizeof(data));
-	if (error != Z_OK) errx(EX_SOFTWARE, "compress: %d", error);
-
-	pngChunk("IDAT", size);
-	pngWrite(deflate, size);
-	pngInt(crc);
-
-	pngChunk("IEND", 0);
-	pngInt(crc);
+	pngData(stdout, (uint8_t *)data, sizeof(data));
+	pngTail(stdout);
 }
diff --git a/bin/scheme.c b/bin/scheme.c
index 0f9f60b9..95123508 100644
--- a/bin/scheme.c
+++ b/bin/scheme.c
@@ -14,16 +14,15 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include <arpa/inet.h>
 #include <err.h>
 #include <math.h>
-#include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sysexits.h>
 #include <unistd.h>
-#include <zlib.h>
+
+#include "png.h"
 
 typedef unsigned uint;
 typedef unsigned char byte;
@@ -188,53 +187,29 @@ static void printMintty(uint n) {
 	printf("%s=%hhd,%hhd,%hhd\n", MinttyNames[n], rgb.r, rgb.g, rgb.b);
 }
 
-static uint32_t crc;
-static void pngWrite(const void *ptr, size_t size) {
-	fwrite(ptr, size, 1, stdout);
-	if (ferror(stdout)) err(EX_IOERR, "(stdout)");
-	crc = crc32(crc, ptr, size);
-}
-static void pngInt(uint32_t host) {
-	uint32_t net = htonl(host);
-	pngWrite(&net, 4);
-}
-static void pngChunk(const char *type, uint32_t size) {
-	pngInt(size);
-	crc = crc32(0, Z_NULL, 0);
-	pngWrite(type, 4);
-}
-
 static void png(uint at, uint to) {
 	if (to - at > 256) to = at + 256;
 
-	uint32_t len = to - at;
-	uint32_t swatchWidth = 64;
-	uint32_t swatchHeight = 64;
-	uint32_t cols = 8;
-	uint32_t rows = (len + cols - 1) / cols;
-	uint32_t width = swatchWidth * cols;
-	uint32_t height = swatchHeight * rows;
+	uint len = to - at;
+	uint swatchWidth = 64;
+	uint swatchHeight = 64;
+	uint cols = 8;
+	uint rows = (len + cols - 1) / cols;
+	uint width = swatchWidth * cols;
+	uint height = swatchHeight * rows;
 
-	pngWrite("\x89PNG\r\n\x1A\n", 8);
+	pngHead(stdout, width, height, 8, PNGIndexed);
 
-	pngChunk("IHDR", 13);
-	pngInt(width);
-	pngInt(height);
-	pngWrite("\x08\x03\x00\x00\x00", 5);
-	pngInt(crc);
-
-	pngChunk("PLTE", 3 * len);
-	for (uint i = at; i < to; ++i) {
-		struct RGB rgb = toRGB(scheme[i]);
-		pngWrite(&rgb, 3);
+	struct RGB rgb[len];
+	for (uint i = 0; i < len; ++i) {
+		rgb[i] = toRGB(scheme[at + i]);
 	}
-	pngInt(crc);
+	pngPalette(stdout, (byte *)rgb, sizeof(rgb));
 
 	uint8_t data[height][1 + width];
 	memset(data, 0, sizeof(data));
 	for (uint32_t y = 0; y < height; ++y) {
-		enum { None, Sub, Up, Average, Paeth };
-		data[y][0] = (y % swatchHeight) ? Up : Sub;
+		data[y][0] = (y % swatchHeight) ? PNGUp : PNGSub;
 	}
 	for (uint i = at; i < to; ++i) {
 		uint p = i - at;
@@ -243,17 +218,8 @@ static void png(uint at, uint to) {
 		data[y][1 + x] = x ? 1 : p;
 	}
 
-	uLong size = compressBound(sizeof(data));
-	byte deflate[size];
-	int error = compress(deflate, &size, (byte *)data, sizeof(data));
-	if (error != Z_OK) errx(EX_SOFTWARE, "compress: %d", error);
-
-	pngChunk("IDAT", size);
-	pngWrite(deflate, size);
-	pngInt(crc);
-
-	pngChunk("IEND", 0);
-	pngInt(crc);
+	pngData(stdout, (byte *)data, sizeof(data));
+	pngTail(stdout);
 }
 
 static void print(void (*fn)(uint), uint at, uint to) {