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https://github.com/excalidraw/excalidraw.git
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Type refactor
Signed-off-by: Mark Tolmacs <mark@lazycat.hu>
This commit is contained in:
Mark Tolmacs
parent
47064a3662
commit
2137f2b806
6 changed files with 63 additions and 262 deletions
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@ -1,5 +1,5 @@
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import { isPoint, pointFrom, pointRotateRads } from "./point";
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import type { CubicBezier, Curve, GenericPoint, Radians } from "./types";
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import { isPoint, pointRotateRads } from "./point";
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import type { Curve, GenericPoint, Radians } from "./types";
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/**
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*
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@ -10,12 +10,12 @@ import type { CubicBezier, Curve, GenericPoint, Radians } from "./types";
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* @returns
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*/
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export function curve<Point extends GenericPoint>(
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a: Point,
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b: Point,
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c: Point,
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d: Point,
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start: Point,
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control1: Point,
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control2: Point,
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end: Point,
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) {
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return [a, b, c, d] as Curve<Point>;
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return [start, control1, control2, end] as Curve<Point>;
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}
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export const curveRotate = <Point extends GenericPoint>(
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@ -26,215 +26,16 @@ export const curveRotate = <Point extends GenericPoint>(
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return curve.map((p) => pointRotateRads(p, origin, angle));
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};
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/**
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*
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* @param pointsIn
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* @param curveTightness
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* @returns
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*/
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export function curveToBezier<Point extends GenericPoint>(
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pointsIn: readonly Point[],
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curveTightness = 0,
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): Point[] {
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const len = pointsIn.length;
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if (len < 3) {
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throw new Error("A curve must have at least three points.");
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}
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const out: Point[] = [];
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if (len === 3) {
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out.push(
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pointFrom(pointsIn[0][0], pointsIn[0][1]), // Points need to be cloned
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pointFrom(pointsIn[1][0], pointsIn[1][1]), // Points need to be cloned
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pointFrom(pointsIn[2][0], pointsIn[2][1]), // Points need to be cloned
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pointFrom(pointsIn[2][0], pointsIn[2][1]), // Points need to be cloned
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);
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} else {
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const points: Point[] = [];
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points.push(pointsIn[0], pointsIn[0]);
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for (let i = 1; i < pointsIn.length; i++) {
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points.push(pointsIn[i]);
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if (i === pointsIn.length - 1) {
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points.push(pointsIn[i]);
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}
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}
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const b: Point[] = [];
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const s = 1 - curveTightness;
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out.push(pointFrom(points[0][0], points[0][1]));
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for (let i = 1; i + 2 < points.length; i++) {
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const cachedVertArray = points[i];
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b[0] = pointFrom(cachedVertArray[0], cachedVertArray[1]);
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b[1] = pointFrom(
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cachedVertArray[0] + (s * points[i + 1][0] - s * points[i - 1][0]) / 6,
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cachedVertArray[1] + (s * points[i + 1][1] - s * points[i - 1][1]) / 6,
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);
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b[2] = pointFrom(
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points[i + 1][0] + (s * points[i][0] - s * points[i + 2][0]) / 6,
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points[i + 1][1] + (s * points[i][1] - s * points[i + 2][1]) / 6,
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);
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b[3] = pointFrom(points[i + 1][0], points[i + 1][1]);
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out.push(b[1], b[2], b[3]);
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}
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}
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return out;
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}
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/**
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*
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* @param t
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* @param controlPoints
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* @returns
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*/
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export const cubicBezierPoint = <Point extends GenericPoint>(
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t: number,
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controlPoints: Curve<Point>,
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): Point => {
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const [p0, p1, p2, p3] = controlPoints;
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const x =
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Math.pow(1 - t, 3) * p0[0] +
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3 * Math.pow(1 - t, 2) * t * p1[0] +
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3 * (1 - t) * Math.pow(t, 2) * p2[0] +
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Math.pow(t, 3) * p3[0];
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const y =
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Math.pow(1 - t, 3) * p0[1] +
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3 * Math.pow(1 - t, 2) * t * p1[1] +
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3 * (1 - t) * Math.pow(t, 2) * p2[1] +
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Math.pow(t, 3) * p3[1];
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return pointFrom(x, y);
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};
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/**
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*
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* @param point
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* @param controlPoints
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* @returns
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*/
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export const cubicBezierDistance = <Point extends GenericPoint>(
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point: Point,
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controlPoints: Curve<Point>,
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) => {
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// Calculate the closest point on the Bezier curve to the given point
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const t = findClosestParameter(point, controlPoints);
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// Calculate the coordinates of the closest point on the curve
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const [closestX, closestY] = cubicBezierPoint(t, controlPoints);
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// Calculate the distance between the given point and the closest point on the curve
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const distance = Math.sqrt(
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(point[0] - closestX) ** 2 + (point[1] - closestY) ** 2,
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);
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return distance;
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};
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const solveCubic = (a: number, b: number, c: number, d: number) => {
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// This function solves the cubic equation ax^3 + bx^2 + cx + d = 0
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const roots: number[] = [];
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const discriminant =
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18 * a * b * c * d -
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4 * Math.pow(b, 3) * d +
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Math.pow(b, 2) * Math.pow(c, 2) -
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4 * a * Math.pow(c, 3) -
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27 * Math.pow(a, 2) * Math.pow(d, 2);
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if (discriminant >= 0) {
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const C = Math.cbrt((discriminant + Math.sqrt(discriminant)) / 2);
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const D = Math.cbrt((discriminant - Math.sqrt(discriminant)) / 2);
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const root1 = (-b - C - D) / (3 * a);
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const root2 = (-b + (C + D) / 2) / (3 * a);
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const root3 = (-b + (C + D) / 2) / (3 * a);
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roots.push(root1, root2, root3);
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} else {
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const realPart = -b / (3 * a);
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const root1 =
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2 * Math.sqrt(-b / (3 * a)) * Math.cos(Math.acos(realPart) / 3);
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const root2 =
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2 *
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Math.sqrt(-b / (3 * a)) *
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Math.cos((Math.acos(realPart) + 2 * Math.PI) / 3);
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const root3 =
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2 *
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Math.sqrt(-b / (3 * a)) *
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Math.cos((Math.acos(realPart) + 4 * Math.PI) / 3);
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roots.push(root1, root2, root3);
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}
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return roots;
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};
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const findClosestParameter = <Point extends GenericPoint>(
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point: Point,
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controlPoints: Curve<Point>,
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) => {
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// This function finds the parameter t that minimizes the distance between the point
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// and any point on the cubic Bezier curve.
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const [p0, p1, p2, p3] = controlPoints;
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// Use the direct formula to find the parameter t
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const a = p3[0] - 3 * p2[0] + 3 * p1[0] - p0[0];
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const b = 3 * p2[0] - 6 * p1[0] + 3 * p0[0];
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const c = 3 * p1[0] - 3 * p0[0];
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const d = p0[0] - point[0];
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const rootsX = solveCubic(a, b, c, d);
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// Do the same for the y-coordinate
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const e = p3[1] - 3 * p2[1] + 3 * p1[1] - p0[1];
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const f = 3 * p2[1] - 6 * p1[1] + 3 * p0[1];
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const g = 3 * p1[1] - 3 * p0[1];
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const h = p0[1] - point[1];
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const rootsY = solveCubic(e, f, g, h);
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// Select the real root that is between 0 and 1 (inclusive)
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const validRootsX = rootsX.filter((root) => root >= 0 && root <= 1);
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const validRootsY = rootsY.filter((root) => root >= 0 && root <= 1);
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if (validRootsX.length === 0 || validRootsY.length === 0) {
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// No valid roots found, use the midpoint as a fallback
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return 0.5;
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}
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// Choose the parameter t that minimizes the distance
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let minDistance = Infinity;
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let closestT = 0;
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for (const rootX of validRootsX) {
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for (const rootY of validRootsY) {
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const distance = Math.sqrt(
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(rootX - point[0]) ** 2 + (rootY - point[1]) ** 2,
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);
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if (distance < minDistance) {
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minDistance = distance;
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closestT = (rootX + rootY) / 2; // Use the average for a smoother result
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}
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}
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}
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return closestT;
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};
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export const isBezier = <Point extends GenericPoint>(
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export const isCurve = <Point extends GenericPoint>(
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c: unknown,
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): c is CubicBezier<Point> => {
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): c is Curve<Point> => {
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return (
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c != null &&
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typeof c === "object" &&
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Object.hasOwn(c, "start") &&
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Object.hasOwn(c, "end") &&
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Object.hasOwn(c, "control1") &&
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Object.hasOwn(c, "control2") &&
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isPoint((c as CubicBezier<Point>).start) &&
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isPoint((c as CubicBezier<Point>).end) &&
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isPoint((c as CubicBezier<Point>).control1) &&
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isPoint((c as CubicBezier<Point>).control2)
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Array.isArray(c) &&
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c.length === 4 &&
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isPoint((c as Curve<Point>)[0]) &&
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isPoint((c as Curve<Point>)[1]) &&
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isPoint((c as Curve<Point>)[2]) &&
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isPoint((c as Curve<Point>)[3])
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);
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};
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@ -101,9 +101,22 @@ export type Polygon<Point extends GenericPoint> = Point[] & {
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};
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/**
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* Cubic bezier curve with four control points
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* Cubic bezier curve where the start and end points are at the 0 and 3 index
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* respectively, and the control points are at the 1 and 2 index respectively.
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*
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* It conveniently maps into the following code:
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*
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* ```javascript
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* canvasCtx.moveTo(start);
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* canvasCtx.bezierCurveTo(control1, control2, end);
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* ```
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*/
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export type Curve<Point extends GenericPoint> = [Point, Point, Point, Point] & {
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export type Curve<Point extends GenericPoint> = [
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start: Point,
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control1: Point,
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control2: Point,
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end: Point,
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] & {
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_brand: "excalimath_curve";
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};
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@ -144,14 +157,3 @@ export type Ellipse<Point extends GenericPoint> = {
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} & {
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_brand: "excalimath_ellipse";
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};
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/**
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* Represents a cubic bezier with 2 control points on the point space of your
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* choosing.
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*/
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export type CubicBezier<P extends GenericPoint> = {
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start: P;
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end: P;
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control1: P;
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control2: P;
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};
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