diff options
Diffstat (limited to 'gfx/png.h')
-rw-r--r-- | gfx/png.h | 108 |
1 files changed, 0 insertions, 108 deletions
diff --git a/gfx/png.h b/gfx/png.h deleted file mode 100644 index 0df4699b..00000000 --- a/gfx/png.h +++ /dev/null @@ -1,108 +0,0 @@ -/* 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 <err.h> -#include <stdint.h> -#include <stdio.h> -#include <stdlib.h> -#include <sysexits.h> - -static inline uint32_t pngCRCTable(uint8_t n) { - static uint32_t table[256]; - if (table[1]) return table[n]; - for (int i = 0; i < 256; ++i) { - table[i] = i; - for (int j = 0; j < 8; ++j) { - table[i] = (table[i] >> 1) ^ (table[i] & 1 ? 0xEDB88320 : 0); - } - } - return table[n]; -} - -static uint32_t pngCRC; - -static inline void pngWrite(FILE *file, const uint8_t *ptr, uint32_t len) { - if (!fwrite(ptr, len, 1, file)) err(EX_IOERR, "pngWrite"); - for (uint32_t i = 0; i < len; ++i) { - pngCRC = pngCRCTable(pngCRC ^ ptr[i]) ^ (pngCRC >> 8); - } -} -static inline void pngInt32(FILE *file, uint32_t n) { - pngWrite(file, (uint8_t []) { n >> 24, n >> 16, n >> 8, n }, 4); -} -static inline void pngChunk(FILE *file, char type[static 4], uint32_t len) { - pngInt32(file, len); - pngCRC = ~0; - pngWrite(file, (uint8_t *)type, 4); -} - -enum { - PNGGrayscale, - PNGTruecolor = 2, - PNGIndexed, - PNGAlpha, -}; - -static inline void pngHead( - FILE *file, uint32_t width, uint32_t height, uint8_t depth, uint8_t color -) { - pngWrite(file, (uint8_t *)"\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, (uint8_t []) { 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); -} - -enum { - PNGNone, - PNGSub, - PNGUp, - PNGAverage, - PNGPaeth, -}; - -static inline void pngData(FILE *file, const uint8_t *data, uint32_t len) { - uint32_t adler1 = 1, adler2 = 0; - for (uint32_t i = 0; i < len; ++i) { - adler1 = (adler1 + data[i]) % 65521; - adler2 = (adler1 + adler2) % 65521; - } - uint32_t zlen = 2 + 5 * ((len + 0xFFFE) / 0xFFFF) + len + 4; - pngChunk(file, "IDAT", zlen); - pngWrite(file, (uint8_t []) { 0x08, 0x1D }, 2); - for (; len > 0xFFFF; data += 0xFFFF, len -= 0xFFFF) { - pngWrite(file, (uint8_t []) { 0x00, 0xFF, 0xFF, 0x00, 0x00 }, 5); - pngWrite(file, data, 0xFFFF); - } - pngWrite(file, (uint8_t []) { 0x01, len, len >> 8, ~len, ~len >> 8 }, 5); - pngWrite(file, data, len); - pngInt32(file, adler2 << 16 | adler1); - pngInt32(file, ~pngCRC); -} - -static inline void pngTail(FILE *file) { - pngChunk(file, "IEND", 0); - pngInt32(file, ~pngCRC); -} |