bool OEAddDepictionHydrogens(OEChem::OEMolBase &mol)

Adds explicit “depiction” hydrogens to the specified OEMolBase. Depiction hydrogens are hydrogens that need to be explicitly drawn in a 2D depiction to faithfully represent tetrahedral atom stereochemistry or cis/trans bond stereochemistry.

The OEAddDepictionHydrogens function identifies all implicit depiction hydrogens (using the OEHasDepictionHydrogens function), and converts them into explicit hydrogens using the OEAddExplicitHydrogens function. This function returns true if any depiction hydrogens were converted into explicit atoms.