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)