Context Class

Begin processing a page.

Begin processing given content stream. The content stream may be a Form XObject, Type3 glyph stream, pattern stream or any other content stream.

Sets the Optional Content Group (OCG) context that should be used when rendering the page. This function can be used to selectively render optional content (such as PDF layers) based on the states of optional content groups in the given context.

Gets the current state.

Sets the current ON-OFF state of the optional-content group (OCG) object in a given context.

The OCG::Context object represents an optional-content context in a document, within which document objects such as words or annotations are visible or hidden. The context keeps track of the ON-OFF states of all of the optional-content groups (OCGs) in a document. Content is or is not visible with respect to the OCG states stored in a specific context. Unlike other objects in OCG namespace, the OCG::Context does not correspond to any explicit PDF structure.

Each PDFView has a default context (PDF::GetOCGContext()) that it uses for on-screen drawing and that determines the default state for any drawing. The context has flags that control whether to draw content that is marked as optional, and whether to draw content that is not marked as optional.

When enumerating page content, OCG::Context can be passed as a parameter in ElementReader.Begin() method. When using PDFDraw, PDFRasterizer, or PDFViewCtrl class to render PDF pages use SetOCGContext() method to select an OC context.

There can be more than one Context object, representing different combinations of OCG states. You can change the states of OCGs within any context. You can build contexts with your own combination of OCG states, and issue drawing or enumeration commands using that context. For example, you can pass an optional-content context to ElementReader.Begin(). You can save the resulting state information as part of the configuration (e.g. using Config::SetInit methods), but the context itself has no corresponding PDF representation, and is not saved.

Sets the Optional Content Group (OCG) context that should be used when viewing the document. This function can be used to change the current OCG context. Optional content, such as PDF layers will be selectively rendered based on the states of optional content groups in the given context.

Gets the Optional Content Group (OCG) context associated with this PDFViewCtrl

Inheritance Hierarchy

SystemObject
pdftron.PDF.OCGContext

Namespace: pdftron.PDF.OCG
Assembly: pdftron (in pdftron.dll) Version: 255.255.255.255

Syntax

C++

JavaScript

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public sealed class Context : IClosable

Public NotInheritable Class Context
	Implements IClosable

public ref class Context sealed : IClosable

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

Type.createClass(
	'pdftron.PDF.OCG.Context',
	null,
	Windows.Foundation.IClosable);

Return Value

Type:
true if this OCG object is in the ON state in a given context, false otherwise.

Return Value

Type:
the Optional Content Group (OCG) context associated with this PDFViewCtrl, or NULL (i.e. context.IsValid()==false) if there is no OCG context associated with the view. If an OCG context associated with the view, optional content, such as PDF layers will be selectively rendered based on the states of optional content groups in the given context.

The Context type exposes the following members.

Constructors

	Name	Description
	Context(Config)	Create a context object that represents an optional-content state of the document from a given configuration.
	Context(Context)	Copy constructor.

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Methods

	Name	Description
	Close
	Equals	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetNonOCDrawing	Gets the non oc drawing.
	GetOCMode	Gets OC drawing mode
	GetState	Gets the state.
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	ResetStates	Sets the sates of all OCGs in the context to ON or OFF.
	SetNonOCDrawing	Sets the non-OC status for this context. Content that is not marked as optional content is drawn (or element.IsOCVisible()) when 'draw_non_OC' is true, and not drawn/visible otherwise.
	SetOCDrawMode	Sets the drawing and enumeration type for this context. This type, together with the visibility determined by the OCG and OCMD states, controls whether content that is marked as optional content is drawn or enumerated.
	SetState	Sets the ON-OFF states for the given optional-content group (OCG) in this context.
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Remarks

When page processing is completed, make sure to call ElementReader.End().

Remarks

When page processing is completed, make sure to call ElementReader.End().

Remarks

Unlike PDFDraw.SetOCGContext() this method copies the given context. As a result, in order to modify the state of OCG groups in the current context use GetOCGContext() to obtain the currently selected content and then modify states.

Reference

pdftron.PDF.OCG Namespace