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Practical Algorithms for Image Analysis
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Practical Algorithms for Image Analysis.iso
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GD
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GD1.2
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WEBGIF.C
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C/C++ Source or Header
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1999-09-11
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4KB
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166 lines
/* Bring in the gd library functions */
#include "gd.h"
/* Bring in standard I/O and string manipulation functions */
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main(int argc, char **argv)
{
FILE *in;
FILE *out;
/* Declare our image pointer */
gdImagePtr im = 0;
int i;
/* We'll clear 'no' once we know the user has made a
reasonable request. */
int no = 1;
/* We'll set 'write' once we know the user's request
requires that the image be written back to disk. */
int write = 0;
/* C programs always get at least one argument; we want at
least one more (the image), more in practice. */
if (argc < 2) {
no = 1;
goto usage;
}
/* The last argument should be the image. Open the file. */
in = fopen(argv[argc-1], "rb");
if (!in) {
fprintf(stderr,
"Error: can't open file %s.\n", argv[argc-1]);
}
/* Now load the image. */
im = gdImageCreateFromGif(in);
fclose(in);
/* If the load failed, it must not be a GIF file. */
if (!im) {
fprintf(stderr,
"Error: %s is not a valid gif file.\n", argv[1]);
exit(1);
}
/* Consider each argument in turn. */
for (i=1; (i < (argc-1)); i++) {
/* -i turns on and off interlacing. */
if (!strcmp(argv[i], "-i")) {
if (i == (argc-2)) {
fprintf(stderr,
"Error: -i specified without y or n.\n");
no = 1;
goto usage;
}
if (!strcmp(argv[i+1], "y")) {
/* Set interlace. */
gdImageInterlace(im, 1);
} else if (!strcmp(argv[i+1], "n")) {
/* Clear interlace. */
gdImageInterlace(im, 0);
} else {
fprintf(stderr,
"Error: -i specified without y or n.\n");
no = 1;
goto usage;
}
i++;
no = 0;
write = 1;
} else if (!strcmp(argv[i], "-t")) {
/* Set transparent index (or none). */
int index;
if (i == (argc-2)) {
fprintf(stderr,
"Error: -t specified without a color table index.\n");
no = 1;
goto usage;
}
if (!strcmp(argv[i+1], "none")) {
/* -1 means not transparent. */
gdImageColorTransparent(im, -1);
} else {
/* OK, get an integer and set the index. */
index = atoi(argv[i+1]);
gdImageColorTransparent(im, index);
}
i++;
write = 1;
no = 0;
} else if (!strcmp(argv[i], "-l")) {
/* List the colors in the color table. */
int j;
/* Tabs used below. */
printf("Index Red Green Blue\n");
for (j=0; (j < gdImageColorsTotal(im)); j++) {
/* Use access macros to learn colors. */
printf("%d %d %d %d\n",
j,
gdImageRed(im, j),
gdImageGreen(im, j),
gdImageBlue(im, j));
}
no = 0;
} else if (!strcmp(argv[i], "-d")) {
/* Output dimensions, etc. */
int t;
printf("Width: %d Height: %d Colors: %d\n",
gdImageSX(im), gdImageSY(im),
gdImageColorsTotal(im));
t = gdImageGetTransparent(im);
if (t != (-1)) {
printf("Transparent index: %d\n", t);
} else {
/* -1 means the image is not transparent. */
printf("Transparent index: none\n");
}
if (gdImageGetInterlaced(im)) {
printf("Interlaced: yes\n");
} else {
printf("Interlaced: no\n");
}
no = 0;
} else {
fprintf(stderr, "Unknown argument: %s\n", argv[i]);
break;
}
}
usage:
if (no) {
/* If the command failed, output an explanation. */
fprintf(stderr,
"Usage: webgif [-i y|n ] [-l] [-t index|off ] [-d] gifname.gif\n");
fprintf(stderr,
"Where -i controls interlace (specify y or n for yes or no),\n");
fprintf(stderr,
"-l outputs a table of color indexes, -t sets the specified\n");
fprintf(stderr,
"color index (0-255 or none) to be the transparent color, and\n");
fprintf(stderr,
"-d reports the dimensions and other characteristics of the image.\n");
fprintf(stderr,
"Note: you may wish to pipe to \"more\" when using the -l option.\n");
}
if (write) {
/* Open a temporary file. */
out = fopen("temp.tmp", "wb");
if (!out) {
fprintf(stderr,
"Unable to write to temp.tmp -- exiting\n");
exit(1);
}
/* Write the new gif. */
gdImageGif(im, out);
fclose(out);
/* Erase the old gif. */
unlink(argv[argc-1]);
/* Rename the new to the old. */
rename("temp.tmp", argv[argc-1]);
}
/* Delete the image from memory. */
if (im) {
gdImageDestroy(im);
}
/* All's well that ends well. */
return 0;
}