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#include <png.h>
#include <stdio.h>
#include <stdlib.h>
#include <setjmp.h>
#include "pam.h"
#include "mallocvar.h"
struct cmdlineInfo {
const char * inputFileName;
};
static void
processCommandLine(int const argc,
char * const argv[],
struct cmdlineInfo * const cmdlineP) {
if (argc-1 < 1)
cmdlineP->inputFileName = "-";
else {
cmdlineP->inputFileName = argv[1];
if (argc-1 > 1)
pm_error("Too many arguments. "
"The only argument is the input file name.");
}
}
static void
convertPamToPng(const struct pam * const pamP,
const tuple * const tuplerow,
png_byte * const pngRow) {
unsigned int col;
for (col = 0; col < pamP->width; ++col) {
unsigned int plane;
for (plane = 0; plane < 4; ++plane)
pngRow[4 * col + plane] = tuplerow[col][plane];
}
}
static void
writeRaster(const struct pam * const pamP,
png_struct * const pngP) {
tuple * tupleRow;
png_byte * pngRow;
tupleRow = pnm_allocpamrow(pamP);
MALLOCARRAY(pngRow, pamP->width * 4);
if (pngRow == NULL)
pm_error("Unable to allocate space for PNG pixel row.");
else {
unsigned int row;
for (row = 0; row < pamP->height; ++row) {
pnm_readpamrow(pamP, tupleRow);
convertPamToPng(pamP, tupleRow, pngRow);
png_write_row(pngP, pngRow);
}
free(pngRow);
}
pnm_freepamrow(tupleRow);
}
static void
pngErrorHandler(png_struct * const pngP,
const char * const message) {
pm_error("Error generating PNG image. libpng says: %s", message);
}
static void
writePng(const struct pam * const pamP,
FILE * const ofP) {
png_struct * pngP;
png_info * infoP;
pngP = png_create_write_struct(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL);
if (!pngP)
pm_error("Could not allocate png struct.");
png_set_error_fn(pngP, NULL, &pngErrorHandler, NULL);
infoP = png_create_info_struct(pngP);
if (!infoP)
pm_error("Could not allocate PNG info structure");
else {
infoP->width = pamP->width;
infoP->height = pamP->height;
infoP->bit_depth = 8;
infoP->color_type = PNG_COLOR_TYPE_RGB_ALPHA;
png_init_io(pngP, ofP);
png_write_info(pngP, infoP);
writeRaster(pamP, pngP);
png_write_end(pngP, infoP);
png_destroy_write_struct(&pngP, &infoP);
}
}
int
main(int argc, char * argv[]) {
FILE * ifP;
struct cmdlineInfo cmdline;
struct pam pam;
pnm_init(&argc, argv);
processCommandLine(argc, argv, &cmdline);
ifP = pm_openr(cmdline.inputFileName);
pnm_readpaminit(ifP, &pam, PAM_STRUCT_SIZE(tuple_type));
if (pam.depth < 4)
pm_error("PAM must have depth at least 4 (red, green, blue, alpha). "
"This one has depth %u", pam.depth);
if (pam.maxval != 255)
pm_error("PAM must have maxval 255. This one has %lu", pam.maxval);
writePng(&pam, stdout);
pm_close(ifP);
return 0;
}
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