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pdftron::PDF::OCG::Context Class Reference

`#include <Context.h>`

## Public Types
enum | OCDrawMode { e_VisibleOC , e_AllOC , e_NoOC }

## Public Member Functions
| Context (const Context &context)
Context & | operator= (const Context &g)
| Context (const class Config &config)
| ~Context ()
bool | IsValid () const
bool | GetState (const class Group &group) const
void | SetState (const class Group &group, bool state)
void | ResetStates (bool all_on)
void | SetNonOCDrawing (bool draw_non_OC)
bool | GetNonOCDrawing () const
void | SetOCDrawMode (OCDrawMode oc_draw_mode)
OCDrawMode | GetOCMode () const
void | Destroy ()
ptrdiff_t | GetHandleInternal ()
| Context (TRN_OCGContext ctx)

## Static Public Member Functions
static Context * | CreateInternal (ptrdiff_t impl)

## Public Attributes
TRN_OCGContext | mp_obj

## Detailed Description

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 PDFView class to render PDF pages use PDFDraw::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.

Definition at line 41 of file Context.h.

## Member Enumeration Documentation

## ◆ OCDrawMode

enum pdftron::PDF::OCG::Context::OCDrawMode

OCDrawMode controls drawing or enumerating the page with respect to optional content. Together with the value of SetNonOCDrawing this mode controls drawing or enumerating content on a page with optional content:

- Content that is marked as optional content is drawn or not drawn according to the OCDrawMode and the visibility state as determined by the Optional Content Groups (OCGs) and OCMDs.
- Content that is not marked as optional content is drawn when GetNonOCDrawing() is true, and not drawn when GetNonOCDrawing() is false.

Enumerator
e_VisibleOC | Draw or enumerate optional content that is visible, according to the current state of Optional Content Groups (OCGs) and Optional Content Membership Dictionaries (OCMDs). This is the default mode.
e_AllOC | Draw or enumerate all optional content, regardless of its visibility state. If the context's 'SetNonOCDrawing' is enabled, all contents of document are shown.
e_NoOC | Draw or enumerate no optional content, regardless of its visibility state. If the context's 'SetNonOCDrawing' is not enabled, nothing is drawn, resulting in a blank page.

Definition at line 124 of file Context.h.

## Constructor & Destructor Documentation

## ◆ Context() [1/3]

pdftron::PDF::OCG::Context::Context | ( | const Context & | context | ) |

Copy constructor.

Parameters

  context | Another context from which to take initial OCG states.

## ◆ Context() [2/3]

pdftron::PDF::OCG::Context::Context | ( | const class Config & | config | ) |

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

Parameters

  config | A configuration from which to take initial OCG states.

## ◆ ~Context()

pdftron::PDF::OCG::Context::~Context | ( |  | ) |

Destructor

## ◆ Context() [3/3]

pdftron::PDF::OCG::Context::Context | ( | TRN_OCGContext | ctx | ) |

## Member Function Documentation

## ◆ CreateInternal()

Context * pdftron::PDF::OCG::Context::CreateInternal | ( | ptrdiff_t | impl | ) |
| static

## ◆ Destroy()

void pdftron::PDF::OCG::Context::Destroy | ( |  | ) |

Frees the native memory of the object.

## ◆ GetHandleInternal()

ptrdiff_t pdftron::PDF::OCG::Context::GetHandleInternal | ( |  | ) |

## ◆ GetNonOCDrawing()

bool pdftron::PDF::OCG::Context::GetNonOCDrawing | ( |  | ) | const

Returns
  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().

## ◆ GetOCMode()

OCDrawMode pdftron::PDF::OCG::Context::GetOCMode | ( |  | ) | const

Returns
  the drawing and enumeration type for this context. For more information, please see SetOCMode() and OCG::Context::OCDrawMode.

## ◆ GetState()

bool pdftron::PDF::OCG::Context::GetState | ( | const class Group & | group | ) | const

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

Parameters

  group | The optional-content group (OCG) that is queried.

## ◆ IsValid()

bool pdftron::PDF::OCG::Context::IsValid | ( |  | ) | const
| inline

Returns
  true is this is a valid (non-null) context, false otherwise.

Definition at line 68 of file Context.h.

## ◆ operator=()

Context & pdftron::PDF::OCG::Context::operator= | ( | const Context & | g | ) |

## ◆ ResetStates()

void pdftron::PDF::OCG::Context::ResetStates | ( | bool | all_on | ) |

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

Parameters

  all_on | A flag used to specify whether the OCG states should be set to ON (if true), or OFF (if false).

## ◆ SetNonOCDrawing()

void pdftron::PDF::OCG::Context::SetNonOCDrawing | ( | bool | draw_non_OC | ) |

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.

Parameters

  draw_non_OC | A flag specifying whether the content that is not marked as optional should be treated as visible.

## ◆ SetOCDrawMode()

void pdftron::PDF::OCG::Context::SetOCDrawMode | ( | OCDrawMode | oc_draw_mode | ) |

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.

Parameters

  oc_draw_mode | A flag specifying the visibility of optional content.

## ◆ SetState()

void pdftron::PDF::OCG::Context::SetState | ( | const class Group & | group,
|  | bool | state )

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

Parameters

  group | The optional-content group (OCG) that is queried.
  state | true for 'ON' and false for 'OFF'.

## Member Data Documentation

## ◆ mp_obj

TRN_OCGContext pdftron::PDF::OCG::Context::mp_obj

Definition at line 172 of file Context.h.

The documentation for this class was generated from the following file:

- PDF/OCG/Context.h