@davepagurek/flo-mat/src/find-mat/find-mats.ts

Medial / Scale Axis Transform (MAT/SAT) Library.

/** @internal */
declare const _debug_: Debug; 

import { beziersToSvgPathStr, simplifyPaths } from 'flo-boolean';
import { Debug } from '../debug/debug.js';
import { Mat } from '../mat/mat.js';
import { findMat  } from './find-mat.js';
import { getSizeParams } from './get-size-params.js';


/**
 * Finds and returns the Medial Axis Transforms (MATs) from the given array of 
 * bezier loops representing shape boundaries.
 * 
 * @param bezierLoops An array of (possibly intersecting) loops with each loop 
 * representing one or more piecewise smooth closed curves (i.e. shapes). Each 
 * loop consists of an array of beziers represented by an array of control 
 * points with 2,3 or 4 elements corresponding to linear, quadratic and cubic 
 * beziers respectively. Each point is a two-element array (ordered pair), the
 * first of which is the x-coordinate and the second the y-coordinate.
 * 
 * @param maxCurviness The maximum value the 'curviness' of a curve can have 
 * before an additional MAT point is inserted in between. Defaults to 0.4. 
 * (Curviness is measured as the total angle in radians between the consecutive 
 * vectors formed by the ordered control points of th bezier curve). The value
 * is clipped in the range `[0.05,3]`.
 * @param maxLength The maximum length a curve can have before an additional MAT 
 * point is inserted. This value is scaled to a reference 1024 x 1024 
 * grid (e.g. if the shape fits in a 512 x 512 axis-aligned box the value will be 
 * halved, e.g. from 10 to 5). Together with maxCurviness it represents a 
 * tolerance for the accuracy of the MAT. Defaults to 4. The value is clipped 
 * in [1,100].
 */
function findMats(
		bezierLoops: number[][][][], 
		maxCurviness = 0.4,
        maxLength = 4): Mat[] {

	// if (typeof _debug_ !== 'undefined') { var timingStart = performance.now(); }

	let maxCoordinate: number;
	let minBezLength: number;
	({ maxCurviness, maxLength, maxCoordinate, minBezLength } = 
		getSizeParams(bezierLoops, maxCurviness, maxLength));

	const loopss = simplifyPaths(bezierLoops);
	// console.log(loopsToSvgPathStr(bezierLoops.map(v => v.map(v => v.map(v => v.map(v => v*2**4))))));
	// console.log(loopsToSvgPathStr(loopss[0].map(loop => loop.beziers)));

	const mats: Mat[] = [];
	for (const loops of loopss) {
		const mat = findMat(
			loops, 
			minBezLength, 
			maxCurviness, 
			maxLength,
			maxCoordinate
		);
		if (mat) { mats.push(mat); }
	}

	return mats;
}


/**
 * Returns an SVG path string representation of the given bezier loops.
 * @param loops An array of loops having an array of bezier curves each given as 
 * an array of control points.
 */
function loopsToSvgPathStr(
		loops: number[][][][]) {

	let str = '';
	for (const loop of loops) {
		str = str + beziersToSvgPathStr(loop) + '\n';
	}

	return str;
}


export { findMats }