/// <summary>
/// Clones the given <see cref="IProjection{TSource, TResult}"/>
/// if the projection is sensitive to the viewport; otherwise, the
/// projection itself is returned unmodified.
/// </summary>
/// <typeparam name="TSource">
/// The <see cref="System.Type"/> of argument to the projection.
/// </typeparam>
/// <typeparam name="TResult">
/// The <see cref="System.Type"/> of the result of the projection.
/// </typeparam>
/// <param name="self">
/// The projection being cloned.
/// </param>
/// <returns>
/// A clone of the specified projection, if possible;
/// <paramref name="self"/> otherwise.
/// </returns>
public static IProjection <TSource, TResult> CloneIfViewportSensitive <TSource, TResult>(
this IProjection <TSource, TResult> self)
{
if (self.DependsOnViewport())
{
return((IProjection <TSource, TResult>)((IViewportSensitiveProjection)self).Clone());
}
return(self);
}