/**
 * Each skeleton vertex is represented by x, y and time. Time can be used to calculate z coordinate.
 */
export declare type Vertex = [number, number, number];
/**
 * Each polygon is represented by an array of vertex indices.
 */
export declare type Polygon = number[];
/**
 * Straight skeleton calculation result.
 */
export interface Skeleton {
    vertices: Vertex[];
    polygons: Polygon[];
}
export declare class SkeletonBuilder {
    private static module;
    /**
     * Initializes the WebAssembly module. Must be called before any other method.
     */
    static init(): Promise<void>;
    /**
     * Builds a skeleton from a GeoJSON polygon.
     * The polygon must have at least one ring. The first ring is always the outer ring, and the rest are inner rings.
     * Outer rings must be counter-clockwise oriented and inner rings must be clockwise oriented.
     * All rings must be weakly simple.
     * Each ring must have a duplicate of the first vertex at the end.
     * @param polygon The GeoJSON polygon.
     */
    static buildFromGeoJSONPolygon(polygon: GeoJSON.Polygon): Skeleton | null;
    /**
     * Builds a skeleton from a polygon represented as an array of rings.
     * The polygon must have at least one ring. The first ring is always the outer ring, and the rest are inner rings.
     * Outer rings must be counter-clockwise oriented and inner rings must be clockwise oriented.
     * All rings must be weakly simple.
     * Each ring must have a duplicate of the first vertex at the end.
     * @param coordinates The polygon represented as an array of rings.
     */
    static buildFromPolygon(coordinates: number[][][]): Skeleton | null;
    private static checkModule;
    private static serializeInput;
}