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/* See LICENSE file for copyright and license details. */
#include <arpa/inet.h>
#include <errno.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <lcms2.h>
#include <png.h>
static char *argv0;
/* ROMM RGB primaries (ISO 22028-2:2013) */
static cmsCIExyYTRIPLE primaries = {
/* x, y, Y */
{ 0.7347, 0.2653, 0.288040 }, /* red */
{ 0.1596, 0.8404, 0.711874 }, /* green */
{ 0.0366, 0.0001, 0.000086 }, /* blue */
};
void
pngerr(png_structp pngs, const char *msg)
{
fprintf(stderr, "%s: libpng: %s\n", argv0, msg);
exit(1);
}
int
main(int argc, char *argv[])
{
cmsHPROFILE in_prof, out_prof;
cmsHTRANSFORM trans;
cmsToneCurve *gamma10, *out_curves[3];
png_structp pngs;
png_infop pngi;
int icc_compression;
uint32_t width, height, icc_len, outrowlen, tmp32, r, i;
uint16_t *inrow, *outrow;
uint8_t **png_row_p, *icc_data;
char *icc_name;
argv0 = argv[0], argc--, argv++;
if (argc) {
fprintf(stderr, "usage: %s\n", argv0);
return 1;
}
/* load png */
pngs = png_create_read_struct(PNG_LIBPNG_VER_STRING, NULL, pngerr,
NULL);
pngi = png_create_info_struct(pngs);
if (!pngs || !pngi) {
fprintf(stderr, "%s: failed to initialize libpng\n", argv0);
return 1;
}
png_init_io(pngs, stdin);
if (png_get_valid(pngs, pngi, PNG_INFO_tRNS))
png_set_tRNS_to_alpha(pngs);
png_set_add_alpha(pngs, 255*257, PNG_FILLER_AFTER);
png_set_expand_gray_1_2_4_to_8(pngs);
png_set_gray_to_rgb(pngs);
png_set_packing(pngs);
png_read_png(pngs, pngi, PNG_TRANSFORM_PACKING |
PNG_TRANSFORM_EXPAND, NULL);
width = png_get_image_width(pngs, pngi);
height = png_get_image_height(pngs, pngi);
png_row_p = png_get_rows(pngs, pngi);
/* icc profile (output linear ROMM RGB (ISO 22028-2:2013)) */
if (png_get_valid(pngs, pngi, PNG_INFO_iCCP)) {
png_get_iCCP(pngs, pngi, &icc_name,
&icc_compression, &icc_data, &icc_len);
if (!(in_prof = cmsOpenProfileFromMem(icc_data,
icc_len)))
goto lcmserr;
} else {
if (!(in_prof = cmsCreate_sRGBProfile()))
goto lcmserr;
}
if (!(gamma10 = cmsBuildGamma(NULL, 1.0)))
goto lcmserr;
out_curves[0] = out_curves[1] = out_curves[2] = gamma10;
if (!(out_prof = cmsCreateRGBProfile(cmsD50_xyY(), &primaries,
out_curves)))
goto lcmserr;
/* allocate output row buffer */
outrowlen = width * strlen("RGBA");
if (!(outrow = malloc(outrowlen * sizeof(uint16_t)))) {
fprintf(stderr, "%s: malloc: out of memory\n", argv0);
return 1;
}
/* write header */
fputs("farbfeld", stdout);
tmp32 = htonl(width);
if (fwrite(&tmp32, sizeof(uint32_t), 1, stdout) != 1)
goto writerr;
tmp32 = htonl(height);
if (fwrite(&tmp32, sizeof(uint32_t), 1, stdout) != 1)
goto writerr;
/* write data */
switch(png_get_bit_depth(pngs, pngi)) {
case 8:
if (!(trans = cmsCreateTransform(in_prof, TYPE_RGBA_8,
out_prof, TYPE_RGBA_16,
INTENT_RELATIVE_COLORIMETRIC,
0)))
goto lcmserr;
for (r = 0; r < height; ++r) {
cmsDoTransform(trans, png_row_p[r], outrow, width);
for (i = 0; i < outrowlen; i++) {
/* re-add alpha */
if (i >= 3 && (i - 3) % 4 == 0)
outrow[i] = 257 * png_row_p[r][i];
/* swap endiannes to BE */
outrow[i] = htons(outrow[i]);
}
if (fwrite(outrow, sizeof(uint16_t), outrowlen,
stdout) != outrowlen)
goto writerr;
}
break;
case 16:
if (!(trans = cmsCreateTransform(in_prof, TYPE_RGBA_16,
out_prof, TYPE_RGBA_16,
INTENT_RELATIVE_COLORIMETRIC,
0)))
goto lcmserr;
for (r = 0; r < height; ++r) {
inrow = (uint16_t *)png_row_p[r];
for (i = 0; i < outrowlen; i++) {
/* swap endianness to LE */
inrow[i] = ntohs(inrow[i]);
}
cmsDoTransform(trans, png_row_p[r], outrow, width);
for (i = 0; i < outrowlen; ++i) {
/* re-add alpha */
if (i >= 3 && (i - 3) % 4 == 0)
outrow[i] = inrow[i];
/* swap endianness to BE */
outrow[i] = htons(outrow[i]);
}
if (fwrite(outrow, sizeof(uint16_t), outrowlen,
stdout) != outrowlen)
goto writerr;
}
break;
default:
fprintf(stderr, "%s: invalid bit-depth\n", argv0);
return 1;
}
png_destroy_read_struct(&pngs, &pngi, NULL);
return 0;
writerr:
fprintf(stderr, "%s: fwrite: ", argv0);
perror(NULL);
return 1;
lcmserr:
fprintf(stderr, "%s: lcms error\n", argv0);
return 1;
}
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