+
+/** @return Ratio corresponding to a given fractional ratio (+/- 0.01), or 0 */
+Ratio const *
+Ratio::from_ratio (float r)
+{
+ vector<Ratio const *>::iterator j = _ratios.begin ();
+ while (j != _ratios.end() && fabs ((*j)->ratio() - r) > 0.01) {
+ ++j;
+ }
+
+ if (j == _ratios.end ()) {
+ return 0;
+ }
+
+ return *j;
+}
+
+Ratio const *
+Ratio::nearest_from_ratio (float r)
+{
+ Ratio const * nearest = 0;
+ float distance = FLT_MAX;
+
+ for (vector<Ratio const *>::iterator i = _ratios.begin (); i != _ratios.end(); ++i) {
+ float const d = fabs ((*i)->ratio() - r);
+ if (d < distance) {
+ distance = d;
+ nearest = *i;
+ }
+ }
+
+ return nearest;
+}