\Header{validDetails}{Customising grid grob Validation}
\keyword{dplot}{validDetails}
\begin{Description}\relax
This generic hook function is called whenever a grid grob is created
or
edited
via \code{grob}, \code{gTree}, \code{grid.edit} or \code{editGrob}.
This provides an opportunity for customising the validation of a
new class derived from grob (or gTree).
\end{Description}
\begin{Usage}
\begin{verbatim}
validDetails(x)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x}] A grid grob. 
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
This function is called by \code{grob}, \code{gTree},
\code{grid.edit} and \code{editGrob}.
A method should be written for classes derived from grob or gTree
to validate the values of slots specific to the new class.
(e.g., see \code{grid:::validDetails.axis}).

Note that the standard slots for grobs and gTrees are automatically
validated (e.g., \code{vp}, \code{gp} slots for grobs and,
in addition, \code{children}, and \code{childrenvp} slots for
gTrees) so only slots specific to a new class need to be addressed.
\end{Details}
\begin{Value}
The function MUST return the validated grob.
\end{Value}
\begin{Author}\relax
Paul Murrell
\end{Author}
\begin{SeeAlso}\relax
\code{\Link{grid.edit}}
\end{SeeAlso}

