@thi.ng/geom-subdiv-curve/kernels.d.ts

Freely customizable, iterative nD subdivision curves for open / closed geometries

import type { ReadonlyVec } from "@thi.ng/vectors";
import type { SubdivKernel } from "./api.js";
/**
 * HOF subdiv kernel function for computing 2 split points from 2 source
 * points, using weighted summation (thi.ng/vectors/addW2)
 *
 * @param u - split coeffs
 * @param v - split coeffs
 */
export declare const kernel2: ([ua, ub]: number[], [va, vb]: number[]) => ([a, b]: ReadonlyVec[]) => import("@thi.ng/vectors").Vec<number>[];
/**
 * HOF subdiv kernel function for computing 2 split points from 3 source
 * points, using weighted summation (thi.ng/vectors/addW3)
 *
 * @param u - split coeffs
 * @param v - split coeffs
 */
export declare const kernel3: ([ua, ub, uc]: number[], [va, vb, vc]: number[]) => ([a, b, c]: ReadonlyVec[]) => import("@thi.ng/vectors").Vec<number>[];
/**
 * HOF subdiv kernel function for computing 2 split points from 5 source
 * points, using weighted summation (thi.ng/vectors/addW5)
 *
 * @param u - split coeffs
 * @param v - split coeffs
 */
export declare const kernel5: ([ua, ub, uc, ud, ue]: number[], [va, vb, vc, vd, ve]: number[]) => ([a, b, c, d, e]: ReadonlyVec[]) => import("@thi.ng/vectors").Vec<number>[];
/**
 * Splits each curve / line segment into halves at midpoint.
 */
export declare const SUBDIV_MID: SubdivKernel;
/**
 * Splits each curve / line segment into 3 parts at 1/3 and 2/3.
 */
export declare const SUBDIV_THIRDS: SubdivKernel;
/**
 * Chaikin subdivision scheme for open curves.
 */
export declare const SUBDIV_CHAIKIN: SubdivKernel;
/**
 * Cubic bezier subdivision scheme. Currently ONLY supported for closed curves.
 */
export declare const SUBDIV_CUBIC: SubdivKernel;
/**
 * Subdivision kernel for Dyn-Levin-Gregory subdivision. Currently ONLY
 * supported for closed curves.
 *
 * @remarks
 * Reference:
 * https://web.archive.org/web/20060816003547/https://algorithmicbotany.org/papers/subgpu.sig2003.pdf
 */
export declare const SUBDIV_DLG: SubdivKernel;
/**
 * Higher-order 2D only subdiv kernel. Takes an array of 2-tuples of `[t,x]`
 * where `t` is the normalized split position (along each edge) and `x` is the
 * normalized displacement amount (relative to edge length). The `closed` flag
 * indicates if to be used for open/closed curves. Returns a
 * {@link SubdivKernel} which results in `displace.length` points for each
 * original edge and displaces each point by `displace[i][1] * edgeLength` units
 * along the normal of the edge.
 *
 * @remarks
 * The original edge end points are always remaining in place. The normalized
 * split positions `t` must be in the open `(0,1)` interval.
 *
 * @example
 * ```ts tangle:../export/subdiv-displace.ts
 * import { subdivide, SUBDIV_DISPLACE } from "@thi.ng/geom-subdiv-curve";
 *
 * // define subdiv kernel w/ custom displacements
 * const kernel = SUBDIV_DISPLACE([[0.25, 0.25], [0.75, -0.25]]);
 *
 * // subdivide polyline with the kernel
 * console.log(
 *   subdivide([[0,0], [100, 100], [200, 0]], [kernel])
 * );
 * // [
 * //   [ 0, 0 ], [ 50, 0 ], [ 50, 100 ], [ 100, 100 ],
 * //   [100, 50 ], [ 200, 50 ], [ 200, 0 ]
 * // ]
 * ```
 *
 * @param displace
 */
export declare const SUBDIV_DISPLACE: (displace: number[][]) => SubdivKernel;
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