Optionalcolor?: stringColor, blck by default
Optionalhidden?: booleantrue to get the created circle masked
OptionallineStyle?: stringLine style (line|-|dot|.|dashdash|--|dashdotdot|-..|dashdotdotdot|-...|dashdashdash|---)
Name (or tag if name is empty) of the center
Optionalopacity?: numberopacity (0 to 1), 1 by default
Radius of the circle or string giving a valid formula for the radius
Optionaltag?: stringTag to be applied on the created circle (if present)
Optionalthickness?: numberStroke thickness
The created circle if isPromiseMode is false or promise that will be resolved when the circle is displayed
Adds the circle of center o and radius r The figure must have a unity length syntaxes
addCircleOr(o, r),addCircleOr(o, r, color),addCircleOr(o, r, color, lineStyle)andaddCircleOr(o, r, color, lineStyle, thickness)are allowed too