Add psf2png

1 files changed, 114 insertions, 0 deletions

diff --git a/bin/psf2png.c b/bin/psf2png.c
new file mode 100644
index 00000000..6106fd89
--- /dev/null
+++ b/bin/psf2png.c
@@ -0,0 +1,114 @@
+/* Copyright (C) 2018  Curtis 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 <string.h>
+#include <sysexits.h>
+#include <zlib.h>
+
+static const uint32_t GlyphCols = 32;
+
+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);
+}
+
+int main(int argc, char *argv[]) {
+	const char *path = NULL;
+	if (argc > 1) path = argv[1];
+	
+	FILE *file = path ? fopen(path, "r") : stdin;
+	if (!file) err(EX_NOINPUT, "%s", path);
+	if (!path) path = "(stdin)";
+
+	struct {
+		uint32_t magic;
+		uint32_t version;
+		uint32_t size;
+		uint32_t flags;
+		struct {
+			uint32_t len;
+			uint32_t size;
+			uint32_t height;
+			uint32_t width;
+		} glyph;
+	} header;
+	size_t len = fread(&header, sizeof(header), 1, file);
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+	if (len < 1) errx(EX_DATAERR, "%s: truncated header", path);
+
+	uint32_t widthBytes = (header.glyph.width + 7) / 8;
+	uint8_t glyphs[header.glyph.len][header.glyph.height][widthBytes];
+	len = fread(glyphs, header.glyph.size, header.glyph.len, file);
+	if (ferror(file)) err(EX_IOERR, "%s", path);
+	if (len < header.glyph.len) {
+		errx(EX_DATAERR, "%s: truncated glyphs", path);
+	}
+	fclose(file);
+
+	pngWrite("\x89PNG\r\n\x1A\n", 8);
+
+	uint32_t width = header.glyph.width * GlyphCols;
+	uint32_t rows = (header.glyph.len + GlyphCols - 1) / GlyphCols;
+	uint32_t height = header.glyph.height * rows;
+
+	pngChunk("IHDR", 13);
+	pngInt(width);
+	pngInt(height);
+	pngWrite("\x08\x00\x00\x00\x00", 5);
+	pngInt(crc);
+
+	uint8_t data[height][1 + width];
+	memset(data, 0, sizeof(data));
+
+	for (uint32_t i = 0; i < header.glyph.len; ++i) {
+		uint32_t row = header.glyph.height * (i / GlyphCols);
+		uint32_t col = 1 + header.glyph.width * (i % GlyphCols);
+		for (uint32_t y = 0; y < header.glyph.height; ++y) {
+			for (uint32_t x = 0; x < header.glyph.width; ++x) {
+				uint8_t bit = glyphs[i][y][x / 8] >> (7 - x % 8) & 1;
+				data[row + y][col + x] = -bit;
+			}
+		}
+	}
+
+	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);
+}