You can use properties of C1PrintDocument:
/// Gets the current generating area of page, returns null if document in not generating state.
public PageAreaBase CurrentPageArea { get; }
/// An amount of available vertical space in the block flow in the currently
/// generating page area, value specified in the ResolvedUnit units.
/// Returns -1 if document in not generating state.
public double AvailableBlockFlowHeight { get; }
/// An amount of available horizontal space in the block flow in the currently
/// generating page area, value specified in the ResolvedUnit units.
/// Returns -1 if document in not generating state.
public double AvailableBlockFlowWidth { get; }
I have attached small sample