+ if (refp == this)
+ return 0.0;
+
+ /*
+ We catch PARENT_L_ == nil case with this, but we crash if we did
+ not ask for the absolute coordinate (ie. REFP == nil.)
+
+ */
+ if (refp == parent_l_)
+ return offset_;
+ else
+ return offset_ + parent_l_->relative_coordinate (refp);