Class CPDFAnnotationHistoryManager

Manages the undo and redo history for PDF annotation actions within a viewer component.

This class extends CPDFHistoryManagerBase and provides methods to interact with the annotation history, including checking if undo/redo actions are available and performing those actions. It also allows registering a listener to monitor changes in the annotation history state.

Usage:

Instantiate with a reference to the PDF viewer component.
Use canUndo() and canRedo() to check if undo/redo actions are available.
Call undo() and redo() to perform undo/redo operations.
Register a listener with setOnHistoryStateChangedListener() to be notified when the history state changes.

Example

const historyManager = pdfReader._annotationsHistoryManager;
historyManager.setOnHistoryStateChangedListener((canUndo, canRedo) => {
  // Update UI based on undo/redo availability
});

Hierarchy

CPDFHistoryManagerBase
- CPDFAnnotationHistoryManager

Index

Constructors

constructor

Methods

handle setOnHistoryStateChangedListener canUndo canRedo undo redo

Constructors

constructor

new CPDFAnnotationHistoryManager(viewerRef: any): CPDFAnnotationHistoryManager
Parameters
- viewerRef: any
Returns CPDFAnnotationHistoryManager
Overrides CPDFHistoryManagerBase.constructor

Methods

handle

handle(event: any): void
Parameters
- event: any
Returns void

setOnHistoryStateChangedListener

setOnHistoryStateChangedListener(
listener: (canUndo: boolean, canRedo: boolean) => void,
): void
Sets a listener to monitor changes in annotation history state. This should be called during annotation operations to indicate whether undo or redo actions are available.
Parameters
- listener: (canUndo: boolean, canRedo: boolean) => void
  A callback function with two parameters: canUndo (whether undo is available) and canRedo (whether redo is available).
Returns void
Example
```
const historyManager = pdfReader._annotationsHistoryManager;
historyManager.setOnHistoryStateChangedListener((canUndo, canRedo) => {
  // Update UI based on undo/redo availability
});
```

canUndo

canUndo(): Promise<boolean>
Checks if an undo operation is possible.

Returns Promise<boolean>
A promise that resolves to true if an undo operation is possible, otherwise false.
Example
```
const manager = pdfReader._annotationsHistoryManager
await manager.canUndo();
```
Overrides CPDFHistoryManagerBase.canUndo

canRedo

canRedo(): Promise<boolean>
Checks if an undo operation is possible.

Returns Promise<boolean>
A promise that resolves to true if a redo operation is possible, otherwise false.
Example
```
const manager = pdfReader._annotationsHistoryManager
await manager.canRedo();
```
Overrides CPDFHistoryManagerBase.canRedo

undo

undo(): Promise<void>
Checks if a redo operation is possible.

Returns Promise<void>
A promise that resolves when the undo operation is complete.
Example
```
const manager = pdfReader._annotationsHistoryManager
await manager.redo();
```
Overrides CPDFHistoryManagerBase.undo

redo

redo(): Promise<void>
Performs a redo operation on the annotation history.

Returns Promise<void>
A promise that resolves when the redo operation is complete.
Example
```
const manager = pdfReader._annotationsHistoryManager
await manager.redo();
```
Overrides CPDFHistoryManagerBase.redo

Class CPDFAnnotationHistoryManager

Example

Hierarchy

Index

Constructors

Methods

Constructors

constructor

Parameters

Returns CPDFAnnotationHistoryManager

Methods

handle

Parameters

Returns void

setOnHistoryStateChangedListener

Parameters

Returns void

Example

canUndo

Returns Promise<boolean>

Example

canRedo

Returns Promise<boolean>

Example

undo

Returns Promise<void>

Example

redo

Returns Promise<void>

Example

Settings

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