PageSource

PageSource

Abstract bridge between a viewer and the underlying page provider.

Subclasses provide page count, metadata, preview bitmaps, and high resolution bitmaps. Sources emit pagechanged and pagecountchanged when those values change.

Constructor

new PageSource()

Source:

Classes

PageSource

Methods

dispose() → {void}

Description:

  • Releases source-owned resources.

Source:
Returns:
Type
void

emit(event, …args) → {void}

Description:

  • Emits a source event.

Source:
Parameters:
Name Type Attributes Description
event string

Event name.
args * <repeatable>

Event arguments.
Returns:
Type
void

(abstract) getPageCount() → {number}

Description:

  • Returns the number of pages exposed by this source.

Source:
Returns:

Page count.

Type
number

(async, abstract) getPageHighRes(_index, _targetEdgePx) → {Promise.<(CanvasImageSource|null)>}

Description:

  • Returns a high-resolution bitmap for a page.

Source:
Parameters:
Name Type Description
_index number

Page index.
_targetEdgePx number

Requested maximum edge in pixels.
Returns:

High-resolution bitmap.

Type
Promise.<(CanvasImageSource|null)>

(abstract) getPageMetadata(_index) → {PageMetadata|null}

Description:

  • Returns metadata for a page.

Source:
Parameters:
Name Type Description
_index number

Page index.
Returns:

Page metadata.

Type
PageMetadata | null

(async, abstract) getPagePreview(_index) → {Promise.<(CanvasImageSource|null)>}

Description:

  • Returns a preview bitmap for a page.

Source:
Parameters:
Name Type Description
_index number

Page index.
Returns:

Preview bitmap.

Type
Promise.<(CanvasImageSource|null)>

notifyPageChanged(index) → {void}

Description:

  • Emits pagechanged for a page index.

Source:
Parameters:
Name Type Description
index number

Page index.
Returns:
Type
void

notifyPageCountChanged() → {void}

Description:

  • Emits pagecountchanged.

Source:
Returns:
Type
void

off(event, fn) → {void}

Description:

  • Removes a source event listener.

Source:
Parameters:
Name Type Description
event string

Event name.
fn function

Listener callback.
Returns:
Type
void

on(event, fn) → {function}

Description:

  • Subscribes to a source event.

Source:
Parameters:
Name Type Description
event string

Event name.
fn function

Listener callback.
Returns:

Unsubscribe function.

Type
function