import type { PDFRef } from '../core/pdf-ref.ts';
import type { LineCapStyle, LineJoinStyle } from './content-stream.ts';
import type { PDFContext } from './pdf-context.ts';
import { PDFResource } from './pdf-resource.ts';
/**
 * Blend mode names available in PDF.
 */
export type BlendMode = 'Normal' | 'Multiply' | 'Screen' | 'Overlay' | 'Darken' | 'Lighten' | 'ColorDodge' | 'ColorBurn' | 'HardLight' | 'SoftLight' | 'Difference' | 'Exclusion' | 'Hue' | 'Saturation' | 'Color' | 'Luminosity';
/**
 * Rendering intent names available in PDF.
 */
export type RenderingIntent = 'AbsoluteColorimetric' | 'RelativeColorimetric' | 'Saturation' | 'Perceptual';
/**
 * Options for creating an ExtGState (Graphics State Parameter
 * Dictionary). All properties are optional; only specified properties
 * will be included in the dictionary.
 */
export type ExtGStateOptions = {
    /**
     * Stroke opacity (alpha). Range: 0.0 (transparent) to 1.0 (opaque).
     *
     * PDF key: `CA`
     */
    strokeOpacity?: number;
    /**
     * Fill opacity (alpha). Range: 0.0 (transparent) to 1.0 (opaque).
     *
     * PDF key: `ca`
     */
    fillOpacity?: number;
    /**
     * Blend mode for transparency compositing.
     *
     * PDF key: `BM`
     */
    blendMode?: BlendMode;
    /**
     * Line width in user space units.
     *
     * PDF key: `LW`
     */
    lineWidth?: number;
    /**
     * Line cap style. Use values from `LineCapStyle` constant.
     *
     * PDF key: `LC`
     */
    lineCap?: LineCapStyle;
    /**
     * Line join style. Use values from `LineJoinStyle` constant.
     *
     * PDF key: `LJ`
     */
    lineJoin?: LineJoinStyle;
    /**
     * Miter limit for line joins.
     *
     * PDF key: `ML`
     */
    miterLimit?: number;
    /**
     * Dash pattern as [dashArray, dashPhase].
     *
     * PDF key: `D`
     */
    dashPattern?: [number[], number];
    /**
     * Rendering intent for color conversions.
     *
     * PDF key: `RI`
     */
    renderingIntent?: RenderingIntent;
    /**
     * Overprint mode for stroke operations.
     *
     * PDF key: `OP`
     */
    strokeOverprint?: boolean;
    /**
     * Overprint mode for fill operations.
     *
     * PDF key: `op`
     */
    fillOverprint?: boolean;
    /**
     * Overprint mode (0 or 1).
     *
     * PDF key: `OPM`
     */
    overprintMode?: 0 | 1;
    /**
     * Flatness tolerance for curve rendering.
     *
     * PDF key: `FL`
     */
    flatness?: number;
    /**
     * Smoothness tolerance for shading.
     *
     * PDF key: `SM`
     */
    smoothness?: number;
    /**
     * Stroke adjustment flag.
     *
     * PDF key: `SA`
     */
    strokeAdjustment?: boolean;
    /**
     * Alpha source flag (whether to use shape or opacity for alpha).
     *
     * PDF key: `AIS`
     */
    alphaIsShape?: boolean;
    /**
     * Text knockout flag.
     *
     * PDF key: `TK`
     */
    textKnockout?: boolean;
};
/**
 * Represents an Extended Graphics State (ExtGState) resource within a PDF document.
 * ExtGState dictionaries allow setting graphics state parameters that cannot be
 * set directly with operators in the content stream.
 *
 * See PDF 1.7, Section 4.3.4
 */
export declare class ExtGState extends PDFResource {
    readonly key: string;
    private readonly _options;
    constructor(options: ExtGStateOptions);
    get options(): Readonly<ExtGStateOptions>;
    register(context: PDFContext): PDFRef;
    /**
     * Computes a unique key based on the options for deduplication.
     */
    private computeKey;
}