+ printf ("Last-Modified: %s\n", time_buffer);
+ }
+
+ /* Print Expires header. */
+ if (data->end >= data->now)
+ {
+ /* The end of the timespan can be seen. */
+ long secs_per_pixel;
+
+ /* FIXME: Handle graphs with width != 400. */
+ secs_per_pixel = (data->end - data->begin) / 400;
+
+ expires = (time_t) (data->now + secs_per_pixel);
+ }
+ else /* if (data->end < data->now) */
+ {
+ expires = (time_t) (data->now + 86400);