import { PdfDocument } from '../pdf-document';
import { PdfLayer } from './layer';
/**
 * The class provides methods and properties to handle the collection of `PdfLayer`.
 * ```typescript
 * // Load an existing PDF document
 * let document: PdfDocument = new PdfDocument(data);
 * // Access the collection of layers in the document
 * let layers: PdfLayerCollection = document.layers;
 * // Save the document
 * document.save('output.pdf');
 * // Destroy the document
 * document.destroy();
 * ```
 */
export declare class PdfLayerCollection {
    /**
     * Whether this collection represents sub-layers.
     *
     * @private
     * @type {boolean}
     */
    _subLayer: boolean;
    /**
     * Internal flag indicating whether resources for layers are present.
     *
     * @private
     * @type {boolean}
     */
    private _isLayerContainsResource;
    /**
     * Document that owns this collection.
     *
     * @private
     * @type {PdfDocument}
     */
    private _document;
    /**
     * Parent layer when this collection represents sublayers.
     *
     * @private
     * @type {PdfLayer}
     */
    private _parent;
    /**
     * Map from reference to PdfLayer for quick lookup.
     *
     * @private
     * @type {Map<_PdfReference, PdfLayer>}
     */
    private _layerDictionary;
    /**
     * Internal counter used when processing BDC/EMC markers.
     *
     * @private
     * @type {number}
     */
    private _bdcCount;
    /**
     * Internal ordered list of layers.
     *
     * @private
     * @type {PdfLayer[]}
     */
    private _list;
    /**
     * Cross-reference used for object resolution.
     *
     * @private
     * @type {_PdfCrossReference}
     */
    private _crossReference;
    /**
     * Catalog associated with the document.
     *
     * @private
     * @type {_PdfCatalog}
     */
    private _catalog;
    /**
     * Initializes a new instance of the `PdfLayerCollection` class with document.
     *
     * @private
     * @param {PdfDocument} document Document.
     */
    constructor(document: PdfDocument);
    /**
     * Initializes a new instance of the `PdfLayerCollection` class with document and layer.
     *
     * @private
     * @param {PdfDocument} document Document.
     * @param {PdfLayer} layer PDF layer.
     */
    constructor(document: PdfDocument, layer: PdfLayer);
    /**
     * Gets the value indicating whether the skip state is active for the internal element.
     *
     * @private
     * @returns {boolean} True if the current BDC count is greater than zero; otherwise, false.
     */
    readonly _isSkip: boolean;
    /**
     * Gets the layer count.
     *
     * @returns {number} Number of layers.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Retrieve layer counts from the layers collection
     * let count: number = layers.count;
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     */
    readonly count: number;
    /**
     * Gets the `PdfLayer` at the specified index.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Retrieve the first layer from the layers collection
     * let layer: PdfLayer = layers.at(0);
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {number} index Layer index.
     * @returns {PdfLayer} Layer at the specified index.
     */
    at(index: number): PdfLayer;
    /**
     * Create a new `PdfLayer` with name
     * add it to the end of the collection.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Add a new layer to the document with the name 'Layer1'
     * let layer: PdfLayer = layers.add('Layer1');
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {string} name Name of the layer.
     * @returns {PdfLayer} Layer with the name specified.
     */
    add(name: string): PdfLayer;
    /**
     * Create a new `PdfLayer` with name and Boolean flag to set the visibility of layer
     * add it to the end of the collection.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Add a new layer to the document with the name 'Layer1' and set visibility to be true
     * let layer: PdfLayer = layers.add('Layer1', true);
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {string} name Name of the layer.
     * @param {boolean} visible Visibility of the layer.
     * @returns {PdfLayer} Layer with the name specified.
     */
    add(name: string, visible: boolean): PdfLayer;
    /**
     * Boolean indicating whether the specified layer exists or not.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Add a new layer to the document with the name 'Layer1'
     * let layer: PdfLayer = layers.add('Layer1');
     * // Check if the layer is present in the layers collection
     * let isPresent: boolean = layers.contains(layer);
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {PdfLayer} layer The layer to be checked.
     * @returns {boolean} Returns true, if the layer exists. Otherwise, false
     */
    contains(layer: PdfLayer): boolean;
    /**
     * Boolean indicating whether the specified layer name exists or not.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Add a new layer to the document with the name 'Layer1'
     * let layer: PdfLayer = layers.add('Layer1');
     * // Check if the layer is present in the layers collection
     * let isPresent: boolean = layers.contains('Layer1');
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {string} name The layer name to be checked.
     * @returns {boolean} Returns true, if the layer exists. Otherwise, false
     */
    contains(name: string): boolean;
    /**
     * Remove all the layers.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Removes all layers from the collection
     * layers.clear();
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @returns {void} Returns nothing.
     */
    clear(): void;
    /**
     * Index of the specified layer.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Add a new layer to the document with the name 'Layer1'
     * let layer: PdfLayer = layers.add('Layer1');
     * // Find the index of the layer in the layers collection
     * let index: number = layers.indexOf(layer);
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {PdfLayer} layer The layer to be checked.
     * @returns {number} Index of the layer.
     */
    indexOf(layer: PdfLayer): number;
    /**
     * Move the `PdfLayer` into the collection at specified index.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Add a new layer to the document with the name 'Layer1'
     * let layer: PdfLayer = layers.add('Layer1');
     * // Add a new layer to the document with the name 'Layer2'
     * let layer1: PdfLayer = layers.add('Layer2');
     * // Move 'layer2' to the first position (index 0)
     * layers.move(0, layer2);
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {number} index Index of the layer.
     * @param {PdfLayer} layer Layer to move.
     * @returns {void} Returns nothing.
     */
    move(index: number, layer: PdfLayer): void;
    /**
     * Remove the `PdfLayer` at the specified index from the collection.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Remove the layer at index 0 (the first layer)
     * layers.removeAt(0);
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {number} index The index of the layer to be removed.
     * @returns {void} Returns nothing.
     */
    removeAt(index: number): void;
    /**
     * Remove the `PdfLayer` at the specified index from the collection.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Remove the layer at index 0 (the first layer) with graphics on page
     * layers.removeAt(0, true);
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {number} index The index of the layer to be removed.
     * @param {boolean} removeGraphicalContent Remove graphical content, if true.
     * @returns {void} Returns nothing.
     */
    removeAt(index: number, removeGraphicalContent: boolean): void;
    /**
     * Remove the `PdfLayer` with layer instance from the collection.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Add a new layer to the document with the name 'Layer1'
     * let layer: PdfLayer = layers.add('Layer1');
     * // Remove the layer from layer collection with instance
     * layers.remove(layer);
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {PdfLayer} layer Layer to remove.
     * @returns {void} Returns nothing.
     */
    remove(layer: PdfLayer): void;
    /**
     * Remove the `PdfLayer` with layer instance from the collection.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Add a new layer to the document with the name 'Layer1'
     * let layer: PdfLayer = layers.add('Layer1');
     * // Remove the layer from layer collection with instance and graphics on page
     * layers.remove(layer, true);
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {PdfLayer} layer Layer to remove.
     * @param {boolean} removeGraphicalContent Remove graphical content, if true.
     * @returns {void} Returns nothing.
     */
    remove(layer: PdfLayer, removeGraphicalContent: boolean): void;
    /**
     * Remove the `PdfLayer` at the layer name from the collection.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Add a new layer to the document with the name 'Layer1'
     * let layer: PdfLayer = layers.add('Layer1');
     * // Remove the layer with name
     * layers.remove('Layer1');
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {string} name Layer name to remove.
     * @returns {void} Returns nothing.
     */
    remove(name: string): void;
    /**
     * Remove the `PdfLayer` at the layer name from the collection.
     *
     * ```typescript
     * // Load an existing PDF document
     * let document: PdfDocument = new PdfDocument(data);
     * // Access the collection of layers in the document
     * let layers: PdfLayerCollection = document.layers;
     * // Add a new layer to the document with the name 'Layer1'
     * let layer: PdfLayer = layers.add('Layer1');
     * // Remove the layer with name and graphics on page
     * layers.remove('Layer1', true);
     * // Save the document
     * document.save('output.pdf');
     * // Destroy the document
     * document.destroy();
     * ```
     *
     * @param {string} name Layer name to remove.
     * @param {boolean} removeGraphicalContent Remove graphical content, if true.
     * @returns {void} Returns nothing.
     */
    remove(name: string, removeGraphicalContent: boolean): void;
    /**
     * Reads print state from a dictionary and applies it to the layer.
     *
     * @private
     * @param {_PdfDictionary} printOption The print option dictionary.
     * @param {PdfLayer} layer The target layer.
     * @returns {void} nothing.
     */
    private _setPrintState;
    /**
     * Adds a layer to the internal list and creates backend objects if required.
     *
     * @private
     * @param {PdfLayer} layer The layer to add.
     * @returns {number} The index of the added layer.
     */
    private _addLayer;
    /**
     * Creates PDF objects for a layer and updates document OCProperties.
     *
     * @private
     * @param {PdfLayer} layer The layer to create.
     * @returns {void} nothing.
     */
    private _createLayer;
    /**
     * Creates the optional content dictionary entries for a layer.
     *
     * @private
     * @param {PdfLayer} layer The layer to create the dictionary for.
     * @returns {Array<_PdfReference>} Array of references added.
     */
    private _createOptionalContentDictionary;
    /**
     * Builds the optional content views dictionary for the document.
     *
     * @private
     * @returns {_PdfDictionary} The created views dictionary.
     */
    private _createOptionalContentViews;
    /**
     * Creates and links print option dictionaries for the specified layer.
     *
     * @private
     * @param {PdfLayer} layer The layer to create print options for.
     * @returns {_PdfReference} Reference to the created usage dictionary.
     */
    private _setPrintOption;
    /**
     * Registers a sublayer and updates document ordering structures.
     *
     * @private
     * @param {_PdfDictionary} ocProperties The OCProperties dictionary.
     * @param {_PdfReference} reference The reference for the layer.
     * @param {PdfLayer} layer The layer instance.
     * @returns {void} nothing.
     */
    private _createSublayer;
    /**
     * Applies locked state to layers based on OCProperties.
     *
     * @private
     * @param {_PdfDictionary} ocProperties The OCProperties dictionary.
     * @returns {void} nothing.
     */
    private _checkLayerLock;
    /**
     * Updates visibility of layers based on OCProperties 'OFF' list.
     *
     * @private
     * @param {_PdfDictionary} ocProperties The OCProperties dictionary.
     * @returns {void} nothing.
     */
    private _checkLayerVisible;
    /**
     * Parses parent/child relationships for layers from OCProperties.
     *
     * @private
     * @param {_PdfDictionary} ocProperties The OCProperties dictionary.
     * @returns {void} nothing.
     */
    private _checkParentLayer;
    /**
     * Recursively parses a layer order array to build parent-child relationships.
     *
     * @private
     * @param {PdfLayer} parent The parent layer in recursion.
     * @param {(_PdfReference | _PdfReference[])[]} array The order array.
     * @param {Map<_PdfReference, PdfLayer>} layerDictionary Map of references to layers.
     * @returns {void} nothing.
     */
    private _parsingLayerOrder;
    /**
     * Reorders internal list to reflect hierarchical layer order from OCProperties.
     *
     * @private
     * @param {_PdfDictionary} ocProperties The OCProperties dictionary.
     * @returns {void} nothing.
     */
    private _createLayerHierarchical;
    /**
     * Adds child layers of a parent into the parent's `layers` collection.
     *
     * @private
     * @param {PdfLayer} layer Parent layer whose children will be added.
     * @returns {void} nothing.
     */
    private _addChildLayer;
    /**
     * Adds a nested layer into the internal list without creating resources.
     *
     * @private
     * @param {PdfLayer} layer The nested layer to add.
     * @returns {number} The index of the added nested layer.
     */
    private _addNestedLayer;
    /**
     * Removes a layer and associated metadata from the document catalog.
     *
     * @private
     * @param {PdfLayer} layer The layer to remove.
     * @param {boolean} removeGraphicalContent Whether to remove graphical content.
     * @returns {void} nothing.
     */
    private _removeLayer;
    /**
     * Removes a layer reference from the OCG group array.
     *
     * @private
     * @param {PdfLayer} layer The layer to remove.
     * @param {_PdfReference[]} ocGroup The OCG reference array.
     * @returns {void} nothing.
     */
    private _removeOCG;
    /**
     * Removes usage references for a layer from usage dictionaries.
     *
     * @private
     * @param {PdfLayer} layer The target layer.
     * @param {_PdfReference[]} _usage Array of usage references.
     * @returns {void} nothing.
     */
    private _removeUsage;
    /**
     * Removes references to a layer from order arrays recursively.
     *
     * @private
     * @param {PdfLayer} layer The layer to remove.
     * @param {(_PdfReference[] | _PdfReference)[]} order The order array to update.
     * @param {(_PdfReference | _PdfReference[])[]} arrayList Helper array used during recursion.
     * @returns {void} nothing.
     */
    private _removeOrder;
    /**
     * Removes layer reference from ON/OFF visibility arrays.
     *
     * @private
     * @param {PdfLayer} layer The layer to remove.
     * @param {_PdfReference[]} on ON references array.
     * @param {_PdfReference[]} off OFF references array.
     * @returns {void} nothing.
     */
    private _removeVisible;
    /**
     * Removes layer reference from locked array.
     *
     * @private
     * @param {PdfLayer} layer The layer to remove.
     * @param {_PdfReference[]} locked Locked references array.
     * @returns {void} nothing.
     */
    private _removeLocked;
    /**
     * Removes graphical content associated with a layer from pages.
     *
     * @private
     * @param {PdfLayer} layer The layer whose content should be removed.
     * @returns {void} nothing.
     */
    private _removeLayerContent;
    /**
     * Processes begin marked content operators and filters out layer content.
     *
     * @private
     * @param {PdfLayer} parser The parser/layer instance.
     * @param {string} operator The content operator.
     * @param {string[]} operands Operator operands.
     * @param {_PdfContentStream} data Output content stream.
     * @param {string} [id] Optional object id string.
     * @returns {void} nothing.
     */
    private _processBeginMarkContent;
    /**
     * Writes an operator and its operands into a content stream, optionally skipping.
     *
     * @private
     * @param {string[]} operands The operands to write.
     * @param {string} operator The operator to write.
     * @param {boolean} skip Whether writing should be skipped based on state.
     * @param {_PdfContentStream} data The target content stream.
     * @returns {void} nothing.
     */
    private _streamWrite;
    /**
     * Inserts a layer reference into the document order at the specified index.
     *
     * @private
     * @param {number} index The insertion index.
     * @param {PdfLayer} layer The layer to insert.
     * @returns {void} nothing.
     */
    private _insertLayer;
}