* Improve genethumb --help message.

git-svn-id: file:///srv/caca.zoy.org/var/lib/svn/libpipi/trunk@2601 92316355-f0b4-4df1-b90c-862c8a59935f

genethumb/genethumb.c

@@ -20,24 +20,31 @@
 #   define myoption option
 #endif
 
+#define DEFAULT_WIDTH 120
+#define DEFAULT_HEIGHT 90
+
 #define MOREINFO "Try `%s --help' for more information.\n"
 
+static void usage(void);
+
 int main(int argc, char *argv[])
 {
     char *srcname = NULL, *dstname = NULL;
     pipi_image_t *src, *dst;
 
-    int i, w = 0, h = 0, bpp = 24;
+    int i, w = DEFAULT_WIDTH, h = DEFAULT_HEIGHT, bpp = 24;
 
     for(;;)
     {
         int option_index = 0;
         static struct myoption long_options[] =
         {
-            { "geometry",    1, NULL, 'g' },
             { "bpp",         1, NULL, 'b' },
+            { "geometry",    1, NULL, 'g' },
+            { "help",        0, NULL, 'h' },
+            { NULL,          0, NULL, 0   },
         };
-        int c = mygetopt(argc, argv, "g:b:", long_options, &option_index);
+        int c = mygetopt(argc, argv, "b:g:h", long_options, &option_index);
 
         if(c == -1)
             break;
@@ -57,6 +64,9 @@ int main(int argc, char *argv[])
             if(strchr(myoptarg, 'x'))
                 h = atoi(strchr(myoptarg, 'x') + 1);
             break;
+        case 'h':
+            usage();
+            return EXIT_SUCCESS;
         default:
             fprintf(stderr, "%s: invalid option -- %c\n", argv[0], c);
             printf(MOREINFO, argv[0]);
@@ -96,3 +106,18 @@ int main(int argc, char *argv[])
     return 0;
 }
 
+static void usage(void)
+{
+    printf("Usage: genethumb [-b bpp] [-g geometry] SOURCE DESTINATION\n");
+    printf("       genethumb -h | --help\n");
+    printf("Create an image thumbnail.\n");
+    printf("\n");
+    printf("Mandatory arguments to long options are mandatory for short options too.\n");
+    printf("  -b, --bpp <bits>          bits per pixel (32 or 16)\n");
+    printf("  -g, --geometry <geometry> target geometry (default %ix%i)\n",
+           DEFAULT_WIDTH, DEFAULT_HEIGHT);
+    printf("  -h, --help                display this help and exit\n");
+    printf("\n");
+    printf("Written by Sam Hocevar. Report bugs to <sam@zoy.org>.\n");
+}
+