Mercurial > resize-gd

comparison resize-gd.c @ 1:7a8f72b27dc3

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added keep aspect ratio; validated size
author meillo@localhost.localdomain
date Sat, 14 Jun 2008 09:08:05 +0200
parents 8c94239b3b3f
children 8e71b54b6e1e
comparison
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0:8c94239b3b3f 1:7a8f72b27dc3
1 /* compile with: gcc -lgd -lpng -lz -ljpeg -lm resize-gd.c */ 1 /*
2 * compile with: gcc -lgd -lpng -lz -ljpeg -lm resize-gd.c
3 * build-depends: libgd2-noxpm-dev | libgd2-dev
4 * depends: libgd2-noxpm | libgd2-xpm
5 *
6 *
7 *
8 * http://www.libgd.org/ImageCreation
9 * http://cpan.uwinnipeg.ca/htdocs/Image-Resize/Image/Resize.pm.html
10 * http://netpbm.sourceforge.net/
11 *
12 */
2 13
3 #include <stdio.h> 14 #include <stdio.h>
4 #include <stdlib.h> /* for atoi() */ 15 #include <stdlib.h> /* for atoi() */
5 #include <string.h> 16 #include <string.h>
17 #include <ctype.h>
6 #include "gd.h" /* Bring in the gd library functions */ 18 #include "gd.h" /* Bring in the gd library functions */
7 19
8 20
9 enum { 21 enum {
10 Png, 22 Png,
13 25
14 26
15 int main(int argc, char* argv[]) { 27 int main(int argc, char* argv[]) {
16 int i; 28 int i;
17 int w, h; 29 int w, h;
30 int width, height;
18 int x, y; 31 int x, y;
19 int type; 32 int type;
20 gdImagePtr im_in; 33 gdImagePtr im_in;
21 gdImagePtr im_out; 34 gdImagePtr im_out;
22 FILE* in; 35 FILE* in;
23 FILE* out; 36 FILE* out;
37 char* sep;
24 38
25 if (argc < 3) { 39 if (argc < 3) {
26 puts("usage: resize-gd <width>x<height> <imagefiles>"); 40 puts("usage: resize-gd <width>x<height> <imagefiles>\n\
41 resize-gd <size> <imagefiles> (keeps aspect ratio)\n");
27 exit(1); 42 exit(1);
28 } 43 }
29 44
30 /* parse width and height */ 45 /* parse width and height */
31 w = atoi(argv[1]); 46 sep = argv[1];
32 h = atoi(strstr(argv[1], "x") + 1); 47 while (isdigit(*sep)) {
33 printf("w: %d h: %d\n", w, h); 48 sep++;
49 }
50 if (*sep == 'x' && isdigit(*(sep+1))) {
51 sep++;
52 while (isdigit(*sep)) {
53 sep++;
54 }
55 }
56 if (*sep != '\0') {
57 fprintf(stderr, "Invalid form of size. Has to be <size> or <width>x<height>.\n");
58 exit(3);
59 }
60
61 width = atoi(argv[1]);
62 sep = strstr(argv[1], "x");
63 if (sep && sep[1] != '\0') {
64 height = atoi(sep + 1);
65 } else {
66 height = -1; /* keep aspect ratio */
67 }
68
34 69
35 /* process images */ 70 /* process images */
36 for (i = 2; i < argc; i++) { 71 for (i = 2; i < argc; i++) {
37 printf("processing file '%s'\n", argv[i]); 72 printf("processing file '%s'\n", argv[i]);
38 73
39 if (strcmp(&(argv[i][strlen(argv[i])-4]), ".png") == 0) { 74 if (strcmp(argv[i]+strlen(argv[i])-4, ".png") == 0) {
40 type = Png; 75 type = Png;
41 } else if (strcmp(&(argv[i][strlen(argv[i])-4]), ".jpg") == 0) { 76 } else if (strcmp(argv[i]+strlen(argv[i])-4, ".jpg") == 0) {
42 type = Jpg; 77 type = Jpg;
43 } else { 78 } else {
44 fprintf(stderr, "unknown filetype\n"); 79 fprintf(stderr, "'%s' has unknown filetype. Filename must end with (lowercase) '.png' or '.jpg'.\n", argv[i]);
45 exit(2); 80 continue;
46 } 81 }
82 /* load image */
83 in = fopen(argv[i], "rb");
47 84
48 /* Load a large png to shrink in the smaller one */
49 in = fopen(argv[i], "rb");
50 if (type == Png) { 85 if (type == Png) {
51 im_in = gdImageCreateFromPng(in); 86 im_in = gdImageCreateFromPng(in);
52 } else if (type == Jpg) { 87 } else if (type == Jpg) {
53 im_in = gdImageCreateFromJpeg(in); 88 im_in = gdImageCreateFromJpeg(in);
54 } 89 }
90 /*
91 if ((im_in = gdImageCreateFromPng(in)) != NULL) {
92 type = Png;
93 } else if ((im_in = gdImageCreateFromJpeg(in)) != NULL) {
94 type = Jpg;
95 } else {
96 fprintf(stderr, "'%s' has unknown filetype. Filename must end with (lowercase) '.png' or '.jpg'.\n", argv[i]);
97 continue;
98 }
99 */
100
55 fclose(in); 101 fclose(in);
56 102
103 /* for keeping aspect ratio */
104 if (height <= 0) {
105 if (im_in->sx > im_in->sy) {
106 w = width;
107 h = width * (1.0 * im_in->sy / im_in->sx);
108 } else {
109 h = width;
110 w = width * (1.0 * im_in->sx / im_in->sy);
111 }
112 } else {
113 w = width;
114 h = height;
115 }
116
117 /* copy-resize the image */
57 im_out = gdImageCreateTrueColor(w, h); 118 im_out = gdImageCreateTrueColor(w, h);
58
59 /* Now copy the large image */
60 gdImageCopyResampled(im_out, im_in, 0, 0, 0, 0, im_out->sx, im_out->sy, im_in->sx, im_in->sy); 119 gdImageCopyResampled(im_out, im_in, 0, 0, 0, 0, im_out->sx, im_out->sy, im_in->sx, im_in->sy);
61 120
62 /* write out */ 121 /* write image */
63 out = fopen(argv[i], "wb"); 122 out = fopen(argv[i], "wb");
64 if (type == Png) { 123 if (type == Png) {
65 gdImagePng(im_out, out); 124 gdImagePng(im_out, out);
66 } else if (type == Jpg) { 125 } else if (type == Jpg) {
67 gdImageJpeg(im_out, out, -1); 126 gdImageJpeg(im_out, out, -1);