comparison Meerwald-dir/wm_cox_e.c @ 24:9f20bce6184e v0.7

move directories, support netpbm 11
author Peter Meerwald-Stadler <pmeerw@pmeerw.net>
date Fri, 20 Dec 2024 13:08:59 +0100
parents Meerwald/wm_cox_e.c@4987db85cfae
children
comparison
equal deleted inserted replaced
23:71dd4b96221b 24:9f20bce6184e
1 #include "wm.h"
2 #include "dct.h"
3 #include "netpbm/pgm.h"
4 #include "sort.h"
5
6 char *progname;
7
8 void usage(void) {
9 fprintf(stderr, "usage: %s [-a n] [-h] [-o file] -s file file\n\n", progname);
10 fprintf(stderr, "\t-a n\t\talpha factor/embedding strength\n");
11 fprintf(stderr, "\t-h\t\tprint usage\n");
12 fprintf(stderr, "\t-o file\t\toutput (watermarked) file\n");
13 fprintf(stderr, "\t-s file\t\tsignature to embed in input image\n");
14 exit(0);
15 }
16
17 int main(int argc, char *argv[]) {
18
19 FILE *in = stdin;
20 FILE *out = stdout;
21 FILE *sig = NULL;
22
23 char output_name[MAXPATHLEN] = "(stdout)";
24 char input_name[MAXPATHLEN] = "(stdin)";
25 char signature_name[MAXPATHLEN];
26
27 int c;
28 int row;
29 int i,j;
30
31 int n;
32
33 double alpha = 0.0;
34 double threshold;
35
36 double *largest;
37 gray **input_image;
38 gray **output_image;
39 double **dcts;
40
41 gray maxval;
42 int rows, cols, format;
43
44 progname = argv[0];
45
46 pgm_init(&argc, argv); wm_init();
47
48 while ((c = getopt(argc, argv, "a:h?o:s:")) != EOF) {
49 switch (c) {
50 case 'a':
51 alpha = atof(optarg);
52 if (alpha <= 0.0) {
53 fprintf(stderr, "%s: alpha factor %f out of range\n", progname, alpha);
54 exit(1);
55 }
56 break;
57 case 'h':
58 case '?':
59 usage();
60 break;
61 case 'o':
62 if ((out = fopen(optarg, "wb")) == NULL) {
63 fprintf(stderr, "%s: unable to open output file %s\n", progname, optarg);
64 exit(1);
65 }
66 strcpy(output_name, optarg);
67 break;
68 case 's':
69 if ((sig = fopen(optarg, "r")) == NULL) {
70 fprintf(stderr, "%s: unable to open signature file %s\n", progname, optarg);
71 exit(1);
72 }
73 strcpy(signature_name, optarg);
74 break;
75 }
76 }
77
78 argc -= optind;
79 argv += optind;
80
81 if (argc > 1) {
82 usage();
83 exit(1);
84 }
85
86 if (argc == 1 && *argv[0] != '-') {
87 if ((in = fopen(argv[0], "rb")) == NULL) {
88 fprintf(stderr, "%s: unable to open input file %s\n", progname, argv[0]);
89 exit(1);
90 }
91 else
92 strcpy(input_name, argv[0]);
93 }
94
95 if (sig) {
96 char line[32];
97 fgets(line, sizeof(line), sig);
98 if (strspn(line, "CXSG") >= 4) {
99 fscanf(sig, "%d\n", &n);
100 if (alpha == 0.0)
101 fscanf(sig, "%lf\n", &alpha);
102 else
103 fscanf(sig, "%*f\n");
104 fscanf(sig, "%*f\n");
105 fscanf(sig, "%*f\n");
106 }
107 else {
108 fprintf(stderr, "%s: invalid signature file %s\n", progname, signature_name);
109 exit(1);
110 }
111 }
112 else {
113 fprintf(stderr, "%s: signature file not specified, use -s file option\n", progname);
114 exit(1);
115 }
116
117 pgm_readpgminit(in, &cols, &rows, &maxval, &format);
118
119 init_dct_NxN(cols, rows);
120
121 dcts = alloc_coeffs(cols, rows);
122 input_image = pgm_allocarray(cols, rows);
123
124 for (row = 0; row < rows; row++)
125 pgm_readpgmrow(in, input_image[row], cols, maxval, format);
126
127 fclose(in);
128
129 output_image = pgm_allocarray(cols, rows);
130
131 fdct_NxN(input_image, dcts);
132
133 largest = malloc((n + 1) * sizeof(double));
134 select_largest_coeffs(dcts[0], cols * rows, n+1, largest);
135 threshold = largest[0];
136 free(largest);
137
138 j = 0;
139 for (i = 0; i < n; i++) {
140 double v;
141
142 while (dcts[j / cols][j % cols] < threshold) j++;
143
144 fscanf(sig, "%lf\n", &v);
145 dcts[j / cols][j % cols] *= (1.0 + alpha * v);
146 j++;
147 }
148
149 idct_NxN(dcts, output_image);
150 free_coeffs(dcts);
151
152 pgm_writepgminit(out, cols, rows, maxval, 0);
153
154 for (row = 0; row < rows; row++)
155 pgm_writepgmrow(out, output_image[row], cols, maxval, 0);
156
157 fclose(out);
158
159 fclose(sig);
160
161 pgm_freearray(output_image, rows);
162 pgm_freearray(input_image, rows);
163
164 exit(0);
165 }

Repositories maintained by Peter Meerwald, pmeerw@pmeerw.net.