#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
/* Bring in standard I/O and string manipulation functions */
#include <stdarg.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif
#include <stdio.h>
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef __clang__
/* Workaround broken clang behavior: https://llvm.org/bugs/show_bug.cgi?id=20144 */
#undef strcmp
#endif
/* Bring in the gd library functions */
#include "gd.h"
#define KEEP_TRANS (-100)
static const char argv0[] = "webpng";
static void usage(const char *msg)
{
/* If the command failed, output an explanation. */
fprintf(msg == NULL ? stdout : stderr,
"Usage: %s [-i y|n] [-l] [-t index|none] [-d] [-a] pngname.png\n"
" -i <y|n> Turns on/off interlace\n"
" -l Prints the table of color indexes\n"
" -t <index> Set the transparent color to the specified index (0-255 or \"none\")\n"
" -d Reports the dimensions and other characteristics of the image\n"
" -a Prints all alpha channels that are not 100%% opaque\n"
"\n"
"If you specify '-' as the input file, stdin/stdout will be used as input/output.\n",
argv0);
if (msg)
fprintf(stderr, "\nError: %s\n", msg);
exit(msg == NULL ? 0 : 1);
}
static void err(const char *fmt, ...)
{
va_list ap;
int e = errno;
fprintf(stderr, "%s: error: ", argv0);
va_start(ap, fmt);
vfprintf(stderr, fmt, ap);
va_end(ap);
if (e)
fprintf(stderr, ": %s", strerror(e));
fputs("\n", stderr);
exit(1);
}
int
main(int argc, char **argv)
{
FILE *in;
FILE *out;
const char *infile;
char *tmpfile;
int i;
int use_stdin_stdout = 0;
int interlace = -100;
int list_color_table = 0;
int trans_col = KEEP_TRANS;
int report_details = 0;
int print_alpha = 0;
/* Declare our image pointer */
gdImagePtr im = 0;
/* We'll set 'write' once we know the user's request
requires that the image be written back to disk. */
int write = 0;
int got_a_flag = 0;
/* Consider each argument in turn. */
opterr = 0;
while ((i = getopt(argc, argv, "i:lt:da")) != -1) {
got_a_flag = 1;
switch (i) {
case 'i':
/* -i turns on and off interlacing. */
if (strcmp(optarg, "y") == 0)
interlace = 1;
else if (strcmp(optarg, "n") == 0)
interlace = 0;
else
usage("-i specified without y or n");
write = 1;
break;
case 'l':
/* List the colors in the color table. */
list_color_table = 1;
break;
case 't':
/* Set transparent index (or none). */
if (strcmp(optarg, "none") == 0) {
/* -1 means not transparent. */
trans_col = -1;
} else {
/* XXX: Should check for errors. */
trans_col = atoi(optarg);
if (trans_col < 0 || trans_col > 255)
err("-t has to be in the range of 0 and 255 (inclusive)");
}
write = 1;
break;
case 'd':
/* Output dimensions, etc. */
report_details = 1;
break;
case 'a':
/* Alpha channel info -- thanks to Wez Furlong */
print_alpha = 1;
break;
case 'h':
usage(NULL);
break;
default:
case '?':
if (optind < argc && strcmp(argv[optind], "--help") == 0)
usage(NULL);
usage("unknown option");
break;
}
}
if (got_a_flag == 0)
usage("missing operation flag");
if (argc == optind)
usage("missing filename");
else if (argc != optind + 1)
usage("can only specify one file");
infile = argv[optind];
if (strcmp(infile, "-") == 0) {
/* - is synonymous with STDIN */
use_stdin_stdout = 1;
in = stdin;
} else
in = fopen(infile, "rb");
if (!in)
err("can't open file %s", infile);
/* Now load the image. */
im = gdImageCreateFromPng(in);
fclose(in);
/* If the load failed, it must not be a PNG file. */
if (!im)
err("%s is not a valid PNG file", infile);
if (list_color_table) {
/* List the colors in the color table. */
if (!im->trueColor) {
int j;
/* Tabs used below. */
printf("Index Red Green Blue Alpha\n");
for (j = 0; j < gdImageColorsTotal(im); ++j) {
/* Use access macros to learn colors. */
printf("%d %d %d %d %d\n", j,
gdImageRed(im, j),
gdImageGreen(im, j),
gdImageBlue(im, j),
gdImageAlpha(im, j));
}
} else
printf("Truecolor image, no palette entries to list.\n");
}
if (report_details) {
/* Output dimensions, etc. */
int t;
printf("Width: %d Height: %d Colors: %d\n",
gdImageSX(im),
gdImageSY(im),
gdImageColorsTotal(im));
/* -1 means the image is not transparent. */
t = gdImageGetTransparent(im);
if (t != -1)
printf("First 100%% transparent index: %d\n", t);
else
printf("First 100%% transparent index: none\n");
if (gdImageGetInterlaced(im))
printf("Interlaced: yes\n");
else
printf("Interlaced: no\n");
}
if (print_alpha) {
/* Alpha channel info -- thanks to Wez Furlong */
int maxx, maxy, x, y, alpha, pix, nalpha = 0;
maxx = gdImageSX(im);
maxy = gdImageSY(im);
printf("alpha channel information:\n");
if (im->trueColor) {
for (y = 0; y < maxy; y++) {
for (x = 0; x < maxx; x++) {
pix = gdImageGetPixel(im, x, y);
alpha = gdTrueColorGetAlpha(pix);
if (alpha > gdAlphaOpaque) {
/* Use access macros to learn colors. */
printf("%d %d %d %d\n",
gdTrueColorGetRed(pix),
gdTrueColorGetGreen(pix),
gdTrueColorGetBlue(pix),
alpha);
nalpha++;
}
}
}
} else
printf("NOT a true color image\n");
printf("%d alpha channels\n", nalpha);
}
/* If no modifications requested, break out. */
if (write == 0) {
gdImageDestroy(im);
return 0;
}
if (interlace == 1)
gdImageInterlace(im, 1);
else if (interlace == 0)
gdImageInterlace(im, 0);
if (trans_col != KEEP_TRANS)
gdImageColorTransparent(im, trans_col);
if (use_stdin_stdout) {
out = stdout;
} else {
/* Open a temporary file. */
size_t filelen = strlen(infile);
size_t len = filelen + 8;
int outfd;
tmpfile = malloc(len);
if (tmpfile == NULL)
err("could not create a tempfile");
memcpy(tmpfile, infile, filelen);
strcpy(tmpfile + filelen, ".XXXXXX");
outfd = mkstemp(tmpfile);
if (outfd == -1)
err("could not open %s", tmpfile);
out = fdopen(outfd, "wb");
if (!out)
err("could not open %s", tmpfile);
}
/* Write the new PNG. */
gdImagePng(im, out);
if (!use_stdin_stdout) {
fclose(out);
/* Erase the old PNG. */
unlink(infile);
/* Rename the new to the old. */
if (rename(tmpfile, infile) != 0)
err("unable to rename %s to %s", infile, tmpfile);
}
/* Delete the image from memory. */
gdImageDestroy(im);
/* All's well that ends well. */
return 0;
}