import Curve from 'fit-curve'
import { bezierCurveTo } from './bezierCurveTo'
/**
* Calculate points for smooth bezier curves passing through a series of points
* uses https://github.com/soswow/fit-curve/blob/master/src/fit-curve.js
* uses ShapePoints.curveError=50 for error value
* @module shape-points/bezierCurveThrough
* @param {(number|number[])} x1 - starting point or array of points [x1, y1, x2, y2, ... xn, yn]
* @param {number} [y1]
* @param {number} [x2]
* @param {number} [y2]
* @param {number} [xn] - ending point
* @param {number} [yn]
* @param {object} [options]
* @param {number} [options.pointsInArc=5]
* @param {number} [options.curveError=50]
* @returns {number[]} [x1, y1, x2, y2, ... xn, yn]
*/
export function bezierCurveThrough()
{
let pointsInArc = 5, curveError = 50
const points = []
if (Array.isArray(arguments[0]))
{
const array = arguments[0]
for (let i = 0; i < array.length; i += 2)
{
points.push([array[i], array[i + 1]])
}
if (arguments.length === 2)
{
pointsInArc = arguments[1].pointsInArc
curveError = arguments[1].curveError
}
}
else
{
let length = arguments.length
if (arguments.length % 2 === 1)
{
length--
pointsInArc = arguments[length].pointsInArc
curveError = arguments[length].curveError
}
for (let i = 0; i < length; i += 2)
{
points.push([arguments[i], arguments[i + 1]])
}
}
// two points creates a line
if (points.length === 2)
{
return [points[0][0], points[0][1], points[1][0], points[1][1]]
}
// not enough points
if (points.length < 4)
{
return []
}
const results = []
const curves = Curve(points, curveError)
for (let i = 0; i < curves.length; i++)
{
const c = curves[i]
results.push(...bezierCurveTo(c[0][0], c[0][1], c[1][0], c[1][1], c[2][0], c[2][1], c[3][0], c[3][1], pointsInArc))
}
return results
}