Fix mistakes, and finish ppmtolss16

Signed-off-by: Mattias Andrée <m@maandree.se>

1 files changed, 60 insertions, 5 deletions

diff --git a/ppmtolss16.c b/ppmtolss16.c
index 1f2ec1a..5db4a39 100644
--- a/ppmtolss16.c
+++ b/ppmtolss16.c
@@ -7,6 +7,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <libquanta.h>
 
 #if defined(__clang__)
 # pragma clang diagnostic ignored "-Wunsafe-buffer-usage"
@@ -31,7 +32,7 @@ static int invert;
 
 
 static void
-writeall(char *data, size_t n)
+writeall(const char *data, size_t n)
 {
 	ssize_t r;
 
@@ -121,6 +122,7 @@ static size_t
 read_dimension(size_t p, size_t *value)
 {
 	size_t digit;
+	*value = 0;
 	for (;;) {
 		if (p == len) {
 			if (eof)
@@ -437,6 +439,55 @@ read_image_bits(void)
 }
 
 
+static void
+quantise(struct liblss16_header *header, int coloured)
+{
+	size_t i, nchannels = coloured ? 3U : 1U;
+	struct libquanta_channel channels[3];
+	struct libquanta_palette *palette;
+	struct libquanta_image *image;
+
+	memset(channels, 0, sizeof(channels));
+
+	for (i = 0; i < nchannels; i++) {
+		channels[i].bits_in = 6;
+		channels[i].bits_out = 6;
+		channels[i].image_width = width;
+		channels[i].image_height = height;
+		channels[i].image_row_size = nchannels * width;
+		channels[i].image_cell_size = nchannels;
+		channels[i].image = &buf[i];
+	}
+
+	palette = libquanta_malloc_palette(16, nchannels);
+	if (!palette) {
+		fprintf(stderr, "%s: libquanta_malloc_palette: %s\n", argv0, strerror(errno));
+		exit(3);
+	}
+
+	image = libquanta_quantise(palette, &channels[0], coloured ? &channels[1] : NULL, &channels[2], NULL);
+	if (!image) {
+		fprintf(stderr, "%s: libquanta_quantise: %s\n", argv0, strerror(errno));
+		exit(3);
+	}
+
+	for (i = 0; i < len; i++)
+		buf[i] = (char)image->image[i];
+
+	for (i = 0; i < palette->size; i++) {
+		header->colour_map[i].r = (uint8_t)palette->palette[i * nchannels + (coloured ? 0U : 0U)];
+		header->colour_map[i].g = (uint8_t)palette->palette[i * nchannels + (coloured ? 1U : 0U)];
+		header->colour_map[i].b = (uint8_t)palette->palette[i * nchannels + (coloured ? 2U : 0U)];
+	}
+	memset(&header->colour_map[palette->size],
+	       header->colour_map[palette->size - 1U].b,
+	       (16U - palette->size) * sizeof(*header->colour_map));
+
+	free(image);
+	free(palette);
+}
+
+
 int
 main(int argc, char *argv[])
 {
@@ -541,19 +592,23 @@ main(int argc, char *argv[])
 		header.colour_map[!invert].g = 63U;
 		header.colour_map[!invert].b = 63U;
 	} else if (maptype == 2) {
-		/* TODO convert to 16 colours -- greyscale values [0, 63], quantize to 16 colours and map Y to (Y, Y, Y) */
+		quantise(&header, 0);
 	} else {
-		/* TODO convert to 16 colours -- [0, 63]-triplet values, quantize to 16 colours */
+		if (len % 3)
+			not_pnm();
+		len /= 3;
+		quantise(&header, 1);
 	}
 
 	liblss16_optimise(&header, (uint8_t *)buf);
 	if (liblss16_encoder_init(&encoder, &header, 1, &error)) {
-		fprintf(stderr, "%s:liblss16_encoder_init: %s\n", argv0, liblss16_encode_strerror(error));
+		fprintf(stderr, "%s: liblss16_encoder_init: %s\n", argv0, liblss16_encode_strerror(error));
 		exit(3);
 	}
 	off = 0;
+
 	do {
-		state = liblss16_encode_from_colour_index(&encoder, wbuf, sizeof(buf), &written,
+		state = liblss16_encode_from_colour_index(&encoder, wbuf, sizeof(wbuf), &written,
 		                                          (const uint8_t *)&buf[off], len - off, &consumed);
 		off += consumed;
 		writeall(wbuf, written);