diff options
| -rw-r--r-- | bin/README | 1 | ||||
| -rw-r--r-- | bin/pngo.c | 42 |
2 files changed, 40 insertions, 3 deletions
diff --git a/bin/README b/bin/README index 94429275..32f9862d 100644 --- a/bin/README +++ b/bin/README @@ -82,6 +82,7 @@ PNG optimizer. Does not support interlaced PNGs. - Discards ancillary chunks - Discards unnecessary alpha channel - Converts unnecessary truecolor to grayscale + - Indexes color if possible - Applies a simple filter type heuristic - Applies zlib's best compression diff --git a/bin/pngo.c b/bin/pngo.c index 3522eb82..95252fff 100644 --- a/bin/pngo.c +++ b/bin/pngo.c @@ -197,9 +197,7 @@ static void writeHeader(void) { static struct { uint32_t len; - struct PACKED { - uint8_t r, g, b; - } entries[256]; + uint8_t entries[256][3]; } palette; static void readPalette(void) { @@ -473,6 +471,43 @@ static void discardColor(void) { header.color &= ~TRUECOLOR; } +static void indexColor(void) { + if (header.color != TRUECOLOR || header.depth != 8) return; + for (uint32_t y = 0; y < header.height; ++y) { + for (uint32_t x = 0; x < header.width; ++x) { + uint32_t i; + for (i = 0; i < palette.len; ++i) { + if (0 == memcmp(palette.entries[i], &lines[y].data[x * 3], 3)) { + break; + } + } + if (i < palette.len) continue; + if (palette.len == 256) return; + memcpy(palette.entries[i], &lines[y].data[x * 3], 3); + palette.len++; + } + } + + uint8_t *ptr = data; + for (uint32_t y = 0; y < header.height; ++y) { + uint8_t *type = ptr++; + uint8_t *data = ptr; + *type = *lines[y].type; + for (uint32_t x = 0; x < header.width; ++x) { + uint32_t i; + for (i = 0; i < palette.len; ++i) { + if (0 == memcmp(palette.entries[i], &lines[y].data[x * 3], 3)) { + break; + } + } + *ptr++ = i; + } + lines[y].type = type; + lines[y].data = data; + } + header.color = INDEXED; +} + static void optimize(const char *inPath, const char *outPath) { if (inPath) { path = inPath; @@ -501,6 +536,7 @@ static void optimize(const char *inPath, const char *outPath) { reconData(); discardAlpha(); discardColor(); + indexColor(); filterData(); free(lines); |