import { _XmlWriter } from './xml-writer';
import { PdfDocument } from './../pdf-document';
import { PdfPage } from './../pdf-page';
import { PdfAnnotation } from './../annotations/annotation';
import { PdfAnnotationCollection } from './../annotations/annotation-collection';
import { _PdfAnnotationType } from './../enumerator';
import { _PdfDictionary, _PdfName, _PdfReference } from './../pdf-primitives';
import { _PdfContentStream } from './../base-stream';
import { _PdfCrossReference } from './../pdf-cross-reference';
import { PdfCheckBoxField, PdfField } from './../form/field';
/**
 * Provides common helpers for exporting and importing annotations and form fields across formats and manages shared state.
 *
 * @private
 */
export declare abstract class _ExportHelper {
    exportAppearance: boolean;
    /**
     * Determines whether export logic should strictly follow the PDF
     * specification for field and annotation serialization.
     *
     * @private
     */
    _asPerSpecification: boolean;
    /**
     * When true, follow specification-specific export behaviors
     *
     * @private
     */
    _skipBorderStyle: boolean;
    /**
     * File name used during export operations.
     *
     * @private
     */
    _fileName: string;
    /**
     * The active PDF document being processed.
     *
     * @private
     */
    _document: PdfDocument;
    /**
     * Cross-reference table for resolving indirect objects.
     *
     * @private
     */
    _crossReference: _PdfCrossReference;
    /**
     * True when performing an annotation export.
     *
     * @private
     */
    _isAnnotationExport: boolean;
    /**
     * True when performing an annotation import.
     *
     * @private
     */
    _isAnnotationImport: boolean;
    /**
     * Internal random key used for some export modes.
     *
     * @private
     */
    _key: string;
    /**
     * Auxiliary form key appended to rich text values.
     *
     * @private
     */
    _formKey: string;
    /**
     * When true, export fields even when empty.
     *
     * @private
     */
    _exportEmptyFields: boolean;
    /**
     * Group name to reference mapping used during export/import.
     *
     * @private
     */
    _groupReferences: Map<string, _PdfReference>;
    /**
     * Holders for grouped dictionaries queued during processing.
     *
     * @private
     */
    _groupHolders: Array<_PdfDictionary>;
    /**
     * Encoding dictionary used for text encoding decisions.
     *
     * @private
     */
    _encodeDictionary: _PdfDictionary;
    /**
     * Requested annotation types for filtered export/import.
     *
     * @private
     */
    _annotationTypes: Array<_PdfAnnotationType>;
    /**
     * Attributes to include when serializing annotations.
     *
     * @private
     */
    _annotationAttributes: Array<string>;
    /**
     * Parsed XML document used during import operations.
     *
     * @private
     */
    _xmlDocument: Document;
    /**
     * Prefix used for embedding rich text payloads.
     *
     * @private
     */
    _richTextPrefix: string;
    /**
     * DOM parser used to parse incoming XML.
     *
     * @private
     */
    _parser: DOMParser;
    /**
     * Temporary table mapping field names to exported values.
     *
     * @private
     */
    _table: Map<any, any>;
    /**
     * Internal map of field name to value arrays gathered during export.
     *
     * @private
     */
    _fields: Map<string, string[]>;
    /**
     * Rich text values keyed by field name.
     *
     * @private
     */
    _richTextValues: Map<string, string>;
    /**
     * Working JSON data buffer used during conversion.
     *
     * @private
     */
    _jsonData: number[];
    /**
     * ASCII code for '{'
     *
     * @private
     */
    _openingBrace: number;
    /**
     * ASCII code for '['
     *
     * @private
     */
    _openingBracket: number;
    /**
     * ASCII code for '}'
     *
     * @private
     */
    _closingBrace: number;
    /**
     * ASCII code for ']'
     *
     * @private
     */
    _closingBracket: number;
    /**
     * ASCII code for ':'
     *
     * @private
     */
    _colon: number;
    /**
     * ASCII code for '"'
     *
     * @private
     */
    _doubleQuotes: number;
    /**
     * ASCII code for ','
     *
     * @private
     */
    _comma: number;
    /**
     * ASCII code for space
     *
     * @private
     */
    _space: number;
    /**
     * Current serialization format (e.g., 'XFDF' or 'FDF').
     *
     * @private
     */
    _format: string;
    /**
     * Current annotation identifier being processed.
     *
     * @private
     */
    _annotationID: string;
    fdfString: string;
    /**
     * True when parsing XFDF into the document.
     *
     * @private
     */
    _xmlImport: boolean;
    /**
     * Exports annotations using the configured format and returns the serialized bytes.
     *
     * @private
     * @param {PdfDocument} [document] Source PDF document to read annotations.
     * @returns {Uint8Array} Serialized annotation payload.
     */
    abstract _exportAnnotations(document?: PdfDocument): Uint8Array;
    /**
     * Exports form fields using the configured format and returns the serialized bytes.
     *
     * @private
     * @param {PdfDocument} document Source PDF document to read form fields.
     * @returns {Uint8Array} Serialized form field payload.
     */
    abstract _exportFormFields(document: PdfDocument): Uint8Array;
    /**
     * Finalizes the current export operation and returns the serialized bytes.
     *
     * @private
     * @returns {Uint8Array} Serialized output for the active format.
     */
    abstract _save(): Uint8Array;
    /**
     * Reads a form field value and stores it in the table using the field name key.
     *
     * @private
     * @param {PdfField} field Field to export.
     * @returns {string | string[]} Exported value as string or list of strings.
     */
    _exportFormFieldsData(field: PdfField): string | string[];
    /**
     * Exports a single form field and writes its value into the table honoring format rules.
     *
     * @private
     * @param {PdfField} field Field to export.
     * @returns {void}
     */
    _exportFormFieldData(field: PdfField): void;
    /**
     * Gets the annotation subtype name from a dictionary.
     *
     * @private
     * @param {_PdfDictionary} dictionary Annotation dictionary to inspect.
     * @returns {string} Subtype name or empty string.
     */
    _getAnnotationType(dictionary: _PdfDictionary): string;
    /**
     * Converts a PDF primitive into a string suitable for attribute or JSON output.
     *
     * @private
     * @param {any} primitive Primitive to convert.
     * @param {boolean} [isJson=false] When true emits boolean as true or false otherwise yes or no.
     * @returns {string} Converted text.
     */
    _getValue(primitive: any, isJson?: boolean): string;
    /**
     * Converts an RGB array into a hex color string.
     *
     * @private
     * @param {any} primitive Source color array with three numeric components in the zero to one range.
     * @returns {string} Hex color string or empty string.
     */
    _getColor(primitive: any): string;
    /**
     * Escapes newline and carriage return characters for safe text output.
     *
     * @private
     * @param {string} value Input string to sanitize.
     * @returns {string} Sanitized string.
     */
    _getValidString(value: string): string;
    /**
     * Attempts to resolve a font dictionary used by an annotation appearance for encoding decisions.
     *
     * @private
     * @param {_PdfDictionary} source Source dictionary that may contain appearance resources.
     * @returns {_PdfDictionary} Font dictionary when found otherwise undefined.
     */
    _getEncodedFontDictionary(source: _PdfDictionary): _PdfDictionary;
    /**
     * Encodes a text value using font encoding or document level PDFDocEncoding when available.
     *
     * @private
     * @param {string} value Text to encode.
     * @param {_PdfDictionary} [dictionary] Optional font resource dictionary to guide encoding.
     * @returns {string} Encoded text or original text.
     */
    _getEncodedValue(value: string, dictionary?: _PdfDictionary): string;
    /**
     * Replaces characters based on differences mapping and font traits to preserve intended glyphs.
     *
     * @private
     * @param {string} input Input text to process.
     * @param {_FontStructure} structure Font structure containing differences and encoding info.
     * @returns {string} Updated text after replacement.
     */
    _replaceNotUsedCharacters(input: string, structure: _FontStructure): string;
    /**
     * Extracts export value from a primitive or array and adapts it for radio or checkbox fields.
     *
     * @private
     * @param {any} primitive Source primitive to read.
     * @param {PdfField} [field] Optional field for context such as radio button selection.
     * @returns {string | string[]} Export value as string or list of strings.
     */
    _getExportValue(primitive: any, field?: PdfField): string | string[];
    /**
     * Registers a reference under a named group and wires reply chains using the NM and IRT entries.
     *
     * @private
     * @param {_PdfReference} reference Reference assigned to the current annotation.
     * @param {_PdfDictionary} dictionary Annotation dictionary providing NM or IRT entries.
     * @returns {void}
     */
    _addReferenceToGroup(reference: _PdfReference, dictionary: _PdfDictionary): void;
    /**
     * Ensures popup annotations are linked to their parent annotation and updates page collections.
     *
     * @private
     * @param {PdfAnnotationCollection} annotations Annotation collection of the page.
     * @param {_PdfReference} reference Reference of the parent annotation.
     * @param {_PdfDictionary} annotationDictionary Parent annotation dictionary.
     * @param {_PdfDictionary} pageDictionary Page dictionary to update.
     * @returns {void}
     */
    _handlePopup(annotations: PdfAnnotationCollection, reference: _PdfReference, annotationDictionary: _PdfDictionary, pageDictionary: _PdfDictionary): void;
    /**
     * Applies collected field values into the document form fields and writes rich text when present.
     *
     * @private
     * @returns {void}
     */
    _importField(): void;
    /**
     * Imports a single form field value or list of values into the target field.
     *
     * @private
     * @param {PdfField} field Target field to update.
     * @param {string[]} values Values to apply to the field.
     * @returns {void}
     */
    _importFieldData(field: PdfField, values: string[]): void;
    /**
     * Checks whether a checkbox field contains a matching export value.
     *
     * @private
     * @param {string} value Value to test against the field export states.
     * @param {PdfCheckBoxField} field Target checkbox field.
     * @returns {boolean} True when the export value is present.
     */
    _containsExportValue(value: string, field: PdfCheckBoxField): boolean;
    /**
     * Checks whether a widget dictionary has an appearance state matching the given value.
     *
     * @private
     * @param {_PdfDictionary} dictionary Widget or field dictionary with appearance states.
     * @param {string} value Appearance state name to test.
     * @returns {boolean} True when a matching state exists.
     */
    _checkSelected(dictionary: _PdfDictionary, value: string): boolean;
    /**
     * Clears all temporary export and import state objects and resets helper properties.
     *
     * @private
     * @returns {void} Clears internal fields used during processing.
     */
    _dispose(): void;
}
/**
 * Provides XFDF based export and import utilities for annotations and form fields with XML serialization.
 *
 * @private
 */
export declare class _XfdfDocument extends _ExportHelper {
    /**
     * Indicates whether color-space values are included or processed
     * in the XFDF structure.
     *
     * @private
     */
    _isColoSpace: boolean;
    /**
     * Initializes the XFDF helper with optional file name for export context.
     *
     * @private
     * @param {string} [fileName] Source or target file name used in XFDF payload.
     */
    constructor(fileName?: string);
    /**
     * Prepares and exports annotations from the document as an XFDF byte array.
     *
     * @private
     * @param {PdfDocument} document Source PDF document to read annotations.
     * @returns {Uint8Array} Generated XFDF payload containing exported annotations.
     */
    _exportAnnotations(document: PdfDocument): Uint8Array;
    /**
     * Prepares and exports form fields from the document as an XFDF byte array.
     *
     * @private
     * @param {PdfDocument} document Source PDF document to read form fields.
     * @returns {Uint8Array} Generated XFDF payload containing exported form fields.
     */
    _exportFormFields(document: PdfDocument): Uint8Array;
    /**
     * Serializes the current XFDF document into bytes writing annotations or fields as configured.
     *
     * @private
     * @returns {Uint8Array} Serialized XFDF data.
     */
    _save(): Uint8Array;
    /**
     * Writes form field entries into the XML writer honoring Acrobat specification mode.
     *
     * @private
     * @param {_XmlWriter} writer Target XML writer.
     * @param {boolean} [isAcrobat=false] Indicates Acrobat specific structure should be used.
     * @returns {void}
     */
    _writeFormFieldData(writer: _XmlWriter, isAcrobat?: boolean): void;
    /**
     * Recursively writes nested field elements and their values into the XML writer.
     *
     * @private
     * @param {Map<any, any>} value Nested field map to serialize.
     * @param {_XmlWriter} writer Target XML writer.
     * @returns {void}
     */
    _writeFieldName(value: Map<any, any>, writer: _XmlWriter): void;
    /**
     * Builds a hierarchical representation of dot separated field names.
     *
     * @private
     * @param {Map<any, any>} table Flat table of field names to values.
     * @returns {Map<any, any>} Nested map of field groups and values.
     */
    _getElements(table: Map<any, any>): Map<any, any>;
    /**
     * Checks whether an annotation matches any requested annotation types.
     *
     * @private
     * @param {PdfAnnotation} annotation Annotation to check.
     * @returns {boolean} True when the annotation type is allowed.
     */
    _checkAnnotationType(annotation: PdfAnnotation): boolean;
    /**
     * Exports a single annotation if it is supported and not a link or uri type.
     *
     * @private
     * @param {PdfAnnotation} annotation Source annotation to export.
     * @param {_XmlWriter} writer Target XML writer.
     * @param {number} pageIndex Page index of the annotation.
     * @returns {void}
     */
    _exportAnnotationData(annotation: PdfAnnotation, writer: _XmlWriter, pageIndex: number): void;
    /**
     * Writes annotation data and attributes into XML using either an annotation or its dictionary.
     *
     * @private
     * @param {_XmlWriter} writer Target XML writer.
     * @param {number} pageIndex Page index of the annotation.
     * @param {PdfAnnotation|_PdfDictionary} source Annotation instance or annotation dictionary.
     * @returns {void}
     */
    _writeAnnotationData(writer: _XmlWriter, pageIndex: number, annotation: PdfAnnotation): void;
    _writeAnnotationData(writer: _XmlWriter, pageIndex: number, dictionary: _PdfDictionary): void;
    /**
     * Writes supported dictionary attributes and nested structures into XML for the current annotation.
     *
     * @private
     * @param {_PdfDictionary} dictionary Annotation dictionary to serialize.
     * @param {number} pageIndex Page index of the annotation.
     * @param {_XmlWriter} writer Target XML writer.
     * @param {boolean} hasAppearance Indicates whether appearance streams should be included.
     * @returns {void}
     */
    _writeDictionary(dictionary: _PdfDictionary, pageIndex: number, writer: _XmlWriter, hasAppearance: boolean): void;
    /**
     * Serializes the AP dictionary as a compact XML buffer for embedding in XFDF.
     *
     * @private
     * @param {_PdfDictionary} appearance Appearance dictionary to serialize.
     * @returns {Uint8Array} XML bytes representing the appearance content.
     */
    _getAppearanceString(appearance: _PdfDictionary): Uint8Array;
    /**
     * Traverses an appearance dictionary and writes its content into the XML writer.
     *
     * @private
     * @param {_XmlWriter} writer Target XML writer.
     * @param {_PdfDictionary} dictionary Appearance dictionary to traverse.
     * @returns {void}
     */
    _writeAppearanceDictionary(writer: _XmlWriter, dictionary: _PdfDictionary): void;
    /**
     * Writes a PDF primitive as a typed XML node handling arrays dictionaries streams names numbers strings and booleans.
     *
     * @private
     * @param {_XmlWriter} writer Target XML writer.
     * @param {any} primitive Primitive value to serialize.
     * @param {_PdfDictionary} dictionary Context dictionary for resolving references.
     * @param {string} [key] Optional key associated with the primitive.
     * @param {boolean} [isNewReference] Indicates a newly created reference for stream handling.
     * @returns {void}
     */
    _writeObject(writer: _XmlWriter, primitive: any, dictionary: _PdfDictionary, key?: string, isNewReference?: boolean): void;
    /**
     * Starts an XML element for a typed primitive and emits the KEY attribute when present.
     *
     * @private
     * @param {_XmlWriter} writer Target XML writer.
     * @param {string} name Element name that represents the primitive type.
     * @param {string} [key] Optional key attribute to write.
     * @returns {void}
     */
    _writePrefix(writer: _XmlWriter, name: string, key?: string): void;
    /**
     * Writes an array of primitives as typed XML nodes.
     *
     * @private
     * @param {_XmlWriter} writer Target XML writer.
     * @param {any[]} array Source array of primitives.
     * @param {_PdfDictionary} dictionary Context dictionary for resolving references.
     * @returns {void}
     */
    _writeArray(writer: _XmlWriter, array: any[], dictionary: _PdfDictionary): void;
    /**
     * Normalizes special characters for XML content depending on direction of conversion.
     *
     * @private
     * @param {string} value Input string to normalize.
     * @param {boolean} [isParsing=false] True when normalizing from XML to plain text.
     * @returns {string} Normalized string with suitable entity substitutions.
     */
    _getFormatedString(value: string, isParsing?: boolean): string;
    /**
     * Maps a dictionary entry into XML attributes writing known keys and formats.
     *
     * @private
     * @param {_XmlWriter} writer Target XML writer.
     * @param {string} key Dictionary key to process.
     * @param {any} primitive Source primitive value.
     * @returns {void}
     */
    _writeAttribute(writer: _XmlWriter, key: string, primitive: any): void;
    /**
     * Writes a single attribute with string conversion and optional lowercase normalization.
     *
     * @private
     * @param {_XmlWriter} writer Target XML writer.
     * @param {string} attribute Attribute name to write.
     * @param {any} primitive Source primitive value.
     * @param {boolean} [isLowerCase=false] When true writes value in lowercase.
     * @returns {void}
     */
    _writeAttributeString(writer: _XmlWriter, attribute: string, primitive: any, isLowerCase?: boolean): void;
    /**
     * Writes an element with raw XML content when value is already formatted.
     *
     * @private
     * @param {_XmlWriter} writer Target XML writer.
     * @param {string} name Element name to create.
     * @param {string} value Raw XML content to inject.
     * @returns {void}
     */
    _writeRawData(writer: _XmlWriter, name: string, value: string): void;
    /**
     * Writes color attributes and optional numeric component into the XML writer.
     *
     * @private
     * @param {_XmlWriter} writer Target XML writer.
     * @param {any} primitive Source color primitive array number or name.
     * @param {string} attribute Attribute name for color output.
     * @param {string} [tag] Optional attribute for numeric component.
     * @returns {void}
     */
    _writeColor(writer: _XmlWriter, primitive: any, attribute: string, tag?: string): void;
    /**
     * Exports measurement dictionary properties and writes formatted sub dictionaries to XML.
     *
     * @private
     * @param {_PdfDictionary} dictionary Source measure dictionary to export.
     * @param {_XmlWriter} writer Target XML writer.
     * @returns {void}
     */
    _exportMeasureDictionary(dictionary: _PdfDictionary, writer: _XmlWriter): void;
    /**
     * Writes a single measurement sub dictionary as attribute set into the XML writer.
     *
     * @private
     * @param {_PdfDictionary} measurementDetails Measurement dictionary to serialize.
     * @param {_XmlWriter} writer Target XML writer.
     * @returns {void}
     */
    _exportMeasureFormatDetails(measurementDetails: _PdfDictionary, writer: _XmlWriter): void;
    /**
     * Imports annotations from XFDF bytes and appends them to the document.
     *
     * @private
     * @param {PdfDocument} document Target PDF document to receive annotations.
     * @param {Uint8Array} data UTF8 encoded XFDF bytes.
     * @returns {void}
     */
    _importAnnotations(document: PdfDocument, data: Uint8Array): void;
    /**
     * Imports form field values from XFDF bytes and applies them to the document form.
     *
     * @private
     * @param {PdfDocument} document Target PDF document to receive form values.
     * @param {Uint8Array} data UTF8 encoded XFDF bytes.
     * @returns {void}
     */
    _importFormData(document: PdfDocument, data: Uint8Array): void;
    /**
     * Reads the root XML element and routes to annotation or form import handlers.
     *
     * @private
     * @param {HTMLElement} root Root element of the XFDF document.
     * @returns {void}
     */
    _readXmlData(root: HTMLElement): void;
    /**
     * Validates the root XFDF element name.
     *
     * @private
     * @param {HTMLElement} element Root element to validate.
     * @returns {void}
     * @throws {Error} When the file is not a valid XFDF document.
     */
    _checkXfdf(element: HTMLElement): void;
    /**
     * Parses XFDF form data section and populates the internal fields table.
     *
     * @private
     * @param {HTMLElement} root Root element containing form fields.
     * @returns {void}
     */
    _parseFormData(root: HTMLElement): void;
    /**
     * Flattens a list of nested field elements into the internal fields table with full names.
     *
     * @private
     * @param {Element[]} list List of field elements to parse.
     * @returns {void}
     */
    _importFormNodes(list: Element[]): void;
    /**
     * Builds the fully qualified field name by walking up the form field hierarchy.
     *
     * @private
     * @param {Element} node Field element from which to derive the full name.
     * @returns {string} Fully qualified field name (e.g., "parent.child.subchild").
     */
    _getFieldName(node: Element): string;
    /**
     * Parses a single annotation element and adds it to the corresponding page.
     *
     * @private
     * @param {Element} element Annotation element to parse.
     * @returns {void}
     */
    _parseAnnotationData(element: Element): void;
    /**
     * Builds an annotation dictionary from an XML element and its attributes and children.
     *
     * @private
     * @param {PdfPage} page Page that will host the annotation.
     * @param {Element} element Annotation element to convert.
     * @returns {_PdfDictionary} Constructed annotation dictionary or empty on unsupported type.
     */
    _getAnnotationDictionary(page: PdfPage, element: Element): _PdfDictionary;
    /**
     * Adds general annotation attributes border style inner elements and measure data to a dictionary.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination dictionary to update.
     * @param {Element} element Source annotation element.
     * @param {PdfPage} page Page that will host the annotation.
     * @returns {void}
     */
    _addAnnotationData(dictionary: _PdfDictionary, element: Element, page: PdfPage): void;
    /**
     * Applies border style attributes from an element to the annotation dictionary.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination annotation dictionary.
     * @param {Element} element Source annotation element with style attributes.
     * @returns {void}
     */
    _addBorderStyle(dictionary: _PdfDictionary, element: Element): void;
    /**
     * Converts element attributes into corresponding dictionary entries for supported keys.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination annotation dictionary.
     * @param {NamedNodeMap} attributes Attribute collection from the source element.
     * @returns {void}
     */
    _applyAttributeValues(dictionary: _PdfDictionary, attributes: NamedNodeMap): void;
    /**
     * Parses a comma separated numeric list into an array of numbers.
     *
     * @private
     * @param {string} value Comma separated numeric list.
     * @returns {number[]} Parsed numeric array.
     */
    _obtainPoints(value: string): number[];
    /**
     * Parses child nodes like popup contents appearance inklist vertices and embedded data.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination annotation dictionary.
     * @param {Element} element Source annotation element to inspect.
     * @param {PdfPage} page Page context used for nested annotation parsing.
     * @returns {void}
     */
    _parseInnerElements(dictionary: _PdfDictionary, element: Element, page: PdfPage): void;
    /**
     * Adds embedded stream data for sound or file attachment annotations.
     *
     * @private
     * @param {Node} child Data node that contains stream bytes.
     * @param {_PdfDictionary} dictionary Destination annotation dictionary.
     * @param {Element} parent Parent annotation element for attribute context.
     * @returns {void}
     */
    _addStreamData(child: Node, dictionary: _PdfDictionary, parent: Element): void;
    /**
     * Creates a sound stream and links it to the annotation dictionary using provided attributes.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination annotation dictionary.
     * @param {Element} element Data element with sound attributes.
     * @param {number[]} raw Raw byte array for sound data.
     * @returns {void}
     */
    _addSound(dictionary: _PdfDictionary, element: Element, raw: number[]): void;
    /**
     * Creates an embedded file stream and filespec dictionary and links them to the annotation.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination annotation dictionary.
     * @param {Element} element Data element with file attributes.
     * @param {number[]} raw Raw byte array for file data.
     * @returns {void}
     */
    _addFileAttachment(dictionary: _PdfDictionary, element: Element, raw: number[]): void;
    /**
     * Decodes appearance XML from base64 and assigns it to the annotation AP dictionary.
     *
     * @private
     * @param {Node} element * @param {Node} element Appearance element containing encoded XML.
     * @param {_PdfDictionary} dictionary Destination annotation dictionary.
     * @returns {void}
     */
    _addAppearanceData(element: Node, dictionary: _PdfDictionary): void;
    /**
     * Parses a typed appearance node and adds the resulting primitive to the target dictionary or stream.
     *
     * @private
     * @param {_PdfDictionary|_PdfContentStream} source Destination dictionary or content stream.
     * @param {Node} child Typed node to parse such as STREAM DICT ARRAY DATA or scalar.
     * @returns {void}
     */
    _getAppearance(source: _PdfDictionary | _PdfContentStream, child: Node): void;
    /**
     * Creates an empty content stream and populates it with parsed appearance entries.
     *
     * @private
     * @param {Element} element Stream element to parse.
     * @returns {_PdfContentStream} Constructed content stream.
     */
    _getStream(element: Element): _PdfContentStream;
    /**
     * Creates a dictionary and populates it with parsed appearance entries.
     *
     * @private
     * @param {Element} element Dictionary element to parse.
     * @returns {_PdfDictionary} Constructed dictionary.
     */
    _getDictionary(element: Element): _PdfDictionary;
    /**
     * Parses an ARRAY node into a JavaScript array of primitives and references.
     *
     * @private
     * @param {Element} element Array element to parse.
     * @returns {any} Parsed array value.
     */
    _getArray(element: Element): any;
    /**
     * Parses a DATA node into a raw byte array based on declared mode and encoding.
     *
     * @private
     * @param {Element} element Data node with MODE and ENCODING attributes.
     * @returns {number[]} Parsed byte array.
     */
    _getData(element: Element): number[];
    /**
     * Appends a typed child element value into the given array.
     *
     * @private
     * @param {any} array Destination array for parsed items.
     * @param {Node} child Typed node to parse and append.
     * @returns {void}
     */
    _addArrayElements(array: any, child: Node): void;
    /**
     * Reads a FIXED element into a number.
     *
     * @private
     * @param {Element} element Fixed element with VAL attribute.
     * @returns {number} Parsed floating point value.
     */
    _getFixed(element: Element): number;
    /**
     * Reads an INT element into a number.
     *
     * @private
     * @param {Element} element Int element with VAL attribute.
     * @returns {number} Parsed integer value.
     */
    _getInt(element: Element): number;
    /**
     * Reads a STRING element into a text value.
     *
     * @private
     * @param {Element} element String element with VAL attribute.
     * @returns {string} Parsed string value.
     */
    _getString(element: Element): string;
    /**
     * Reads a NAME element into a PDF name object.
     *
     * @private
     * @param {Element} element Name element with VAL attribute.
     * @returns {_PdfName} Parsed name object.
     */
    _getName(element: Element): _PdfName;
    /**
     * Reads a BOOL element into a boolean value.
     *
     * @private
     * @param {Element} element Bool element with VAL attribute.
     * @returns {boolean} Parsed boolean value.
     */
    _getBoolean(element: Element): boolean;
    /**
     * Builds and attaches the Measure dictionary to the annotation based on nested measure elements.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination annotation dictionary.
     * @param {Element} element Annotation element containing measure data.
     * @returns {void}
     */
    _addMeasureDictionary(dictionary: _PdfDictionary, element: Element): void;
    /**
     * Copies supported measurement attributes from an element into a measurement dictionary.
     *
     * @private
     * @param {Element} element Measurement element containing attributes.
     * @param {_PdfDictionary} dictionary Destination measurement dictionary.
     * @returns {void}
     */
    _addElements(element: Element, dictionary: _PdfDictionary): void;
    /**
     * Updates a dictionary with a string value when present.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination dictionary to update.
     * @param {string} key Entry key to set.
     * @param {string} value String value to store.
     * @returns {void}
     */
    _addString(dictionary: _PdfDictionary, key: string, value: string): void;
    /**
     * Updates a dictionary with an integer value when present.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination dictionary to update.
     * @param {string} key Entry key to set.
     * @param {string} value String numeric text to convert.
     * @returns {void}
     */
    _addInt(dictionary: _PdfDictionary, key: string, value: string): void;
    /**
     * Updates a dictionary with a floating point value when present.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination dictionary to update.
     * @param {string} key Entry key to set.
     * @param {string} value String numeric text to convert.
     * @returns {void}
     */
    _addFloat(dictionary: _PdfDictionary, key: string, value: string): void;
    /**
     * Updates a dictionary with an array of numbers when present.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination dictionary to update.
     * @param {number[]} points Numeric array to store.
     * @param {string} key Entry key to set.
     * @returns {void}
     */
    _addFloatPoints(dictionary: _PdfDictionary, points: number[], key: string): void;
    /**
     * Adds a parsed primitive to a dictionary using the KEY attribute of the XML element.
     *
     * @private
     * @param {any} primitive Parsed primitive to store.
     * @param {_PdfDictionary} dictionary Destination dictionary to update.
     * @param {Element} element Source element containing the KEY attribute.
     * @returns {void}
     */
    _addKey(primitive: any, dictionary: _PdfDictionary, element: Element): void;
    /**
     * Applies line ending styles from attributes head and tail to the annotation dictionary.
     *
     * @private
     * @param {_PdfDictionary} dictionary Destination annotation dictionary.
     * @param {Element} element Source annotation element with head and tail.
     * @returns {void}
     */
    _addLineEndStyle(dictionary: _PdfDictionary, element: Element): void;
}
/**
 * Extracts font metadata and encoding details from a font dictionary and provides convenient accessors.
 *
 * @private
 */
export declare class _FontStructure {
    /**
     * Source font dictionary backing this helper.
     *
     * @private
     */
    _dictionary: _PdfDictionary;
    /**
     * Cached mapping of character code differences to glyph names.
     *
     * @private
     */
    _differencesDictionary: Map<string, string>;
    /**
     * Resolved font subtype (e.g., 'Type1', 'TrueType').
     *
     * @private
     */
    _fontType: string;
    /**
     * Base encoding name when present on the font's encoding dictionary.
     *
     * @private
     */
    _baseFontEncoding: string;
    /**
     * Computed font encoding name normalized for processing.
     *
     * @private
     */
    _fontEncoding: string;
    /**
     * Resolved internal font name used for lookups.
     *
     * @private
     */
    _fontName: string;
    /**
     * Creates a font structure helper bound to a font dictionary.
     *
     * @private
     *
     * @param {_PdfDictionary} dictionary Source font dictionary.
     */
    constructor(dictionary: _PdfDictionary);
    readonly differencesDictionary: Map<string, string>;
    readonly baseFontEncoding: string;
    readonly fontEncoding: string;
    readonly fontName: string;
    /**
     * Resolves the font encoding from the font dictionary and normalizes identity encodings.
     *
     * @private
     * @returns {string} Resolved encoding name.
     */
    _getFontEncoding(): string;
    /**
     * Builds a differences dictionary mapping character codes to characters using the font encoding.
     *
     * @private
     * @returns {Map<string, string>} Differences dictionary.
     */
    _getDifferencesDictionary(): Map<string, string>;
    /**
     * Extracts and normalizes the font name by removing subsets styles and hex sequences.
     *
     * @private
     * @returns {string} Normalized font name.
     */
    _getFontName(): string;
    /**
     * Decodes hex escape sequences in a font name into unicode characters.
     *
     * @private
     * @param {string} fontName Encoded font name containing hash based hex sequences.
     * @returns {string} Decoded font name.
     */
    _decodeHexFontName(fontName: string): string;
}