import { type DfPoint } from '../../../../../../ng-draw-flow.interfaces';
/**
 * Computes the geometric center between two endpoints **and**
 * returns the half-length (offset) on each axis.
 *
 * Tuple structure:
 *   [centerX, centerY, offsetX, offsetY]
 *
 * These values are later used for label placement and
 * “long-edge” detection in the renderer.
 */
export declare function getSmoothStepEdgeCenter({ source, target, }: {
    source: DfPoint;
    target: DfPoint;
}): [number, number, number, number];