1 /* 2 * libexif example program to extract an EXIF thumbnail from an image 3 * and save it into a new file. 4 * 5 * Placed into the public domain by Dan Fandrich 6 */ 7 8 #include <stdio.h> 9 #include <libexif/exif-loader.h> 10 11 int main(int argc, char **argv) 12 { 13 int rc = 1; 14 ExifLoader *l; 15 16 if (argc < 2) { 17 printf("Usage: %s image.jpg\n", argv[0]); 18 printf("Extracts a thumbnail from the given EXIF image.\n"); 19 return rc; 20 } 21 22 /* Create an ExifLoader object to manage the EXIF loading process */ 23 l = exif_loader_new(); 24 if (l) { 25 ExifData *ed; 26 27 /* Load the EXIF data from the image file */ 28 exif_loader_write_file(l, argv[1]); 29 30 /* Get a pointer to the EXIF data */ 31 ed = exif_loader_get_data(l); 32 33 /* The loader is no longer needed--free it */ 34 exif_loader_unref(l); 35 l = NULL; 36 if (ed) { 37 /* Make sure the image had a thumbnail before trying to write it */ 38 if (ed->data && ed->size) { 39 FILE *thumb; 40 char thumb_name[1024]; 41 42 /* Try to create a unique name for the thumbnail file */ 43 snprintf(thumb_name, sizeof(thumb_name), 44 "%s_thumb.jpg", argv[1]); 45 46 thumb = fopen(thumb_name, "wb"); 47 if (thumb) { 48 /* Write the thumbnail image to the file */ 49 fwrite(ed->data, 1, ed->size, thumb); 50 fclose(thumb); 51 printf("Wrote thumbnail to %s\n", thumb_name); 52 rc = 0; 53 } else { 54 printf("Could not create file %s\n", thumb_name); 55 rc = 2; 56 } 57 } else { 58 printf("No EXIF thumbnail in file %s\n", argv[1]); 59 rc = 1; 60 } 61 /* Free the EXIF data */ 62 exif_data_unref(ed); 63 } 64 } 65 return rc; 66 } 67
