NAME

       Picture - composite structured graphic

SYNOPSIS

       #include <Unidraw/Graphic/picture.h>

DESCRIPTION

       A Picture defines a composition of graphic objects.  A picture has its own graphics state,
       which it concatenates with its children's state when  it  is  drawn  or  erased.   Picture
       adopts  the  default  concatenation  semantics  supported  by  the Graphic base class: The
       picture's graphics state effectively overrides its children's so that they are drawn  with
       the  picture's  state  information substituted for their own.  A child's attribute is used
       only when the picture does not already define it.  Moreover, each child's  transformer  is
       postmultiplied  by  the picture's transformer when the picture is drawn; thus children are
       drawn relative to the picture's coordinate system.

PUBLIC OPERATIONS

       Picture(Graphic* = nil)
              Construct a new picture, optionally supply a graphic from which to copy an  initial
              set of graphics state.  Picture is derived from FullGraphic and therefore defines a
              full set of graphics state.

       virtual ~Picture()
              The picture deletes its children when it is deleted.

       boolean IsEmpty()
              Picture defines IsEmpty  in  addition  to  the  standard  Graphic  child  traversal
              operations to provide a convenient way to check if the picture has any children.

PROTECTED OPERATIONS

       Graphic* graphic(UList*)
       UList* Elem(Iterator)
              Convenience  functions  for  extracting  a graphic from a UList element and a UList
              from an iterator.

SEE ALSO

       Graphic(3U), Iterator(3U), Transformer(3I), UList(3U), pspaint(3U)