Group Class

The OCG::Group object represents an optional-content group. This corresponds to a PDF OCG dictionary representing a collection of graphic objects that can be made visible or invisible (Section 4.10.1 'Optional Content Groups' in PDF Reference). Any graphic content of the PDF can be made optional, including page contents, XObjects, and annotations. The specific content objects in the group have an OC entry in the PDF as part of the surrounding marked content or in the XObject dictionary. The group itself is a named object that can be typically manipulated through a Layers panel in a PDF viewer.

In the simplest case, the group's ON-OFF state makes the associated content visible or hidden. The ON-OFF state of a group can be toggled for a particular context (OCG::Context), and a set of states is kept in a configuration (OCG::Config). The visibility can depend on more than one group in an optional-content membership dictionary (OCG::OCMD), and can also be affected by the context's draw mode (OCGContext::OCDrawMode).

A group has an Intent entry, broadly describing the intended use. A group's content is considered to be optional (that is, the group's state is considered in its visibility) if any intent in its list matches an intent of the context. The intent list of the context is usually set from the intent list of the document configuration.

A Usage dictionary entry provides more specific intended usage information than an intent entry. Possible key values are: CreatorInfo, Language, Export, Zoom, Print, View, User, PageElement. The usage value can act as a kind of metadata, describing the sort of things that belong to the group, such as text in French, fine detail on a map, or a watermark. The usage values can also be used by the AutoState mechanism to make decisions about what groups should be on and what groups should be off. The AutoState mechanism considers the usage information in the OCGs, the AS Array of the configuration, and external factors; for example, the language the application is running in, the current zoom level on the page, or whether the page is being printed.

public sealed class Group

Public NotInheritable Class Group

public ref class Group sealed

pdftron.PDF.OCG.Group = function();

Type.createClass(
	'pdftron.PDF.OCG.Group');