Class 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.

Inheritance

System.Object

Context

Implements

System.IDisposable

Inherited Members

System.Object.Equals(System.Object)

System.Object.Equals(System.Object, System.Object)

System.Object.GetHashCode()

System.Object.GetType()

System.Object.MemberwiseClone()

System.Object.ToString()

System.Object.ReferenceEquals(System.Object, System.Object)

Namespace: pdftron.PDF.OCG

Assembly: PDFNetiOS.dll

Syntax

public class Context : IDisposable

Constructors

Context(Config)

Create a context object that represents an optional-content state of the document from a given configuration.

Declaration

public Context(Config config)

Parameters

Type	Name	Description
Config	config	A configuration from which to take initial OCG states.

Exceptions

Type	Condition
PDFNetException	PDFNetException the PDFNet exception

Context(Context)

Copy constructor.

Declaration

public Context(Context context)

Parameters

Type	Name	Description
Context	context	Another context from which to take initial OCG states.

Exceptions

Type	Condition
PDFNetException	PDFNetException the PDFNet exception

Methods

Destroy()

Declaration

public void Destroy()

Dispose()

Declaration

public void Dispose()

Dispose(Boolean)

Declaration

protected virtual void Dispose(bool disposing)

Parameters

Type	Name	Description
System.Boolean	disposing

Finalize()

Releases all resources used by the Context

Declaration

protected void Finalize()

GetNonOCDrawing()

Gets the non oc drawing.

Declaration

public bool GetNonOCDrawing()

Returns

Type	Description
System.Boolean	the non-OC status for this context. The flag indicates whether the content that is not marked as optional should be treated as visible. For more information, please see SetNonOCDrawing().

Exceptions

Type	Condition
PDFNetException	PDFNetException the PDFNet exception

GetOCMode()

Gets OC drawing mode

Declaration

public Context.OCDrawMode GetOCMode()

Returns

Type	Description
Context.OCDrawMode	OC drawing mode

GetState(Group)

Gets the state.

Declaration

public bool GetState(Group group)

Parameters

Type	Name	Description
Group	group	The optional-content group (OCG) that is queried.

Returns

Type	Description
System.Boolean	the ON-OFF states (true or false) for the given optional-content group (OCG) in this OC context.

Exceptions

Type	Condition
PDFNetException	PDFNetException the PDFNet exception

ResetStates(Boolean)

Sets the sates of all OCGs in the context to ON or OFF.

Declaration

public void ResetStates(bool all_on)

Parameters

Type	Name	Description
System.Boolean	all_on	A flag used to specify whether the OCG states should be set to ON (if true), or OFF (if false).

Exceptions

Type	Condition
PDFNetException	PDFNetException the PDFNet exception

SetNonOCDrawing(Boolean)

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.

Declaration

public void SetNonOCDrawing(bool draw_non_OC)

Parameters

Type	Name	Description
System.Boolean	draw_non_OC	draw_non_OC A flag specifying whether the content that is not marked as optional should be treated as visible.

Exceptions

Type	Condition
PDFNetException	PDFNetException the PDFNet exception

SetOCDrawMode(Context.OCDrawMode)

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.

Declaration

public void SetOCDrawMode(Context.OCDrawMode oc_draw_mode)

Parameters

Type	Name	Description
Context.OCDrawMode	oc_draw_mode	A flag specifying the visibility of optional content.

Exceptions

Type	Condition
PDFNetException	PDFNetException the PDFNet exception

SetState(Group, Boolean)

Sets the ON-OFF states for the given optional-content group (OCG) in this context.

Declaration

public void SetState(Group group, bool state)

Parameters

Type	Name	Description
Group	group	The optional-content group (OCG) that is queried.
System.Boolean	state	true for 'ON' and false for 'OFF'.

Exceptions

Type	Condition
PDFNetException	PDFNetException the PDFNet exception

Implements

System.IDisposable