code: public double getWidthForBond(IBond bond, RendererModel model) {
          double scale = model.getParameter(Scale.class).getValue();
          if (this.overrideBondWidth != -1) {
              return this.overrideBondWidth / scale;
          } else {
              return model.getParameter(BondWidth.class).getValue() / scale;
          }
      }
docs: Determine the width of a bond, returning either the width defined
  in the model, or the override width. Note that this will be scaled
  to the space of the model.
  
  @param bond the bond to determine the width for
  @param model the renderer model
  @return a double in chem-model space