7.4 Other Operations on Pictures

The picture defines several other operations to query and manipulate the graphical objects in the picture and the picture itself. The most important ones are listed below, see the interface description for the rest.

NoOfGOs.

Returns the number of graphical objects in the list.

IsEmpty.

Returns true if the list is empty.

IsMember.

Takes a graphical object as argument and returns true if the graphical object is in the list.