Fix arc line intersection, add tests to element line intersections

This commit is contained in:
Mark Tolmacs 2024-10-02 22:17:28 +02:00
parent a50ac0ebff
commit c53c37ba69
No known key found for this signature in database
11 changed files with 292 additions and 589 deletions

View file

@ -34,6 +34,9 @@ import {
ellipse,
arc,
radians,
cartesian2Polar,
normalizeRadians,
radiansToDegrees,
} from "../../math";
import type { Mutable } from "../utility-types";
import { getCurvePathOps } from "../../utils/geometry/shape";
@ -694,17 +697,18 @@ export const createDiamondSide = (
export const createDiamondArc = (
start: GlobalPoint,
end: GlobalPoint,
c: GlobalPoint,
r: number,
) => {
const c = pointFrom<GlobalPoint>(
(start[0] + end[0]) / 2,
(start[1] + end[1]) / 2,
const [, startAngle] = cartesian2Polar(
pointFrom(start[0] - c[0], start[1] - c[1]),
);
const [, endAngle] = cartesian2Polar(pointFrom(end[0] - c[0], end[1] - c[1]));
return arc(
c,
r,
radians(Math.asin((start[1] - c[1]) / r)),
radians(Math.asin((end[1] - c[1]) / r)),
normalizeRadians(startAngle), // normalizeRadians(radians(startAngle - Math.PI / 2)),
normalizeRadians(endAngle), // normalizeRadians(radians(endAngle - Math.PI / 2)),
);
};

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@ -0,0 +1,179 @@
import { intersectElementWithLine } from "./collision";
import { newElement } from "./newElement";
import { pointFrom } from "../../math";
import { ROUNDNESS } from "..";
describe("intersection with element", () => {
// it("intersect with rectangle", () => {
// expect(
// intersectElementWithLine(
// newElement({
// type: "rectangle",
// x: -5,
// y: -5,
// width: 10,
// height: 10,
// roundness: null,
// }),
// pointFrom(1, 1),
// pointFrom(10, 10),
// ),
// ).toEqual([pointFrom(5, 5), pointFrom(-5, -5)]);
// expect(
// intersectElementWithLine(
// newElement({
// type: "rectangle",
// x: -5,
// y: -5,
// width: 10,
// height: 10,
// roundness: null,
// }),
// pointFrom(-1, -1),
// pointFrom(-10, -10),
// ),
// ).toEqual([pointFrom(-5, -5), pointFrom(5, 5)]);
// expect(
// intersectElementWithLine(
// newElement({
// type: "rectangle",
// x: -5,
// y: -5,
// width: 10,
// height: 10,
// roundness: {
// type: ROUNDNESS.ADAPTIVE_RADIUS,
// },
// }),
// pointFrom(1, 1),
// pointFrom(10, 10),
// ).map((p) =>
// pointFrom(Math.round(p[0] * 100) / 100, Math.round(p[1] * 100) / 100),
// ),
// ).toEqual([pointFrom(4.27, 4.27), pointFrom(-4.27, -4.27)]);
// expect(
// intersectElementWithLine(
// newElement({
// type: "rectangle",
// x: -5,
// y: -5,
// width: 10,
// height: 10,
// roundness: {
// type: ROUNDNESS.ADAPTIVE_RADIUS,
// },
// }),
// pointFrom(-1, -1),
// pointFrom(-10, -10),
// ).map((p) =>
// pointFrom(Math.round(p[0] * 100) / 100, Math.round(p[1] * 100) / 100),
// ),
// ).toEqual([pointFrom(-4.27, -4.27), pointFrom(4.27, 4.27)]);
// });
it("intersect with diamond", () => {
// expect(
// intersectElementWithLine(
// newElement({
// type: "diamond",
// x: -20,
// y: -20,
// width: 40,
// height: 40,
// roundness: null,
// }),
// pointFrom(-30, 0),
// pointFrom(-25, 0),
// ),
// ).toEqual([pointFrom(-20, 0), pointFrom(20, 0)]);
// expect(
// intersectElementWithLine(
// newElement({
// type: "diamond",
// x: -20,
// y: -20,
// width: 40,
// height: 40,
// roundness: null,
// }),
// pointFrom(0, -30),
// pointFrom(0, -25),
// ),
// ).toEqual([pointFrom(0, -20), pointFrom(0, 20)]);
// expect(
// intersectElementWithLine(
// newElement({
// type: "diamond",
// x: -20,
// y: -20,
// width: 40,
// height: 40,
// roundness: {
// type: ROUNDNESS.PROPORTIONAL_RADIUS,
// },
// }),
// pointFrom(-30, 0),
// pointFrom(-25, 0),
// ).map((p) =>
// pointFrom(Math.round(p[0] * 100) / 100, Math.round(p[1] * 100) / 100),
// ),
// ).toEqual([pointFrom(-21.46, 0), pointFrom(21.46, 0)]);
// console.log(
// intersectElementWithLine(
// newElement({
// type: "diamond",
// x: -20,
// y: -20,
// width: 40,
// height: 40,
// roundness: {
// type: ROUNDNESS.PROPORTIONAL_RADIUS,
// },
// }),
// pointFrom(0, -30),
// pointFrom(0, -25),
// ).map((p) =>
// pointFrom(Math.round(p[0] * 100) / 100, Math.round(p[1] * 100) / 100),
// ),
// );
expect(
intersectElementWithLine(
newElement({
type: "diamond",
x: -20,
y: -20,
width: 40,
height: 40,
roundness: {
type: ROUNDNESS.PROPORTIONAL_RADIUS,
},
}),
pointFrom(0, -30),
pointFrom(0, -25),
).map((p) =>
pointFrom(Math.round(p[0] * 100) / 100, Math.round(p[1] * 100) / 100),
),
).toEqual([pointFrom(0, -17.93), pointFrom(0, 17.93)]);
expect(
intersectElementWithLine(
newElement({
type: "diamond",
x: -20,
y: -20,
width: 40,
height: 40,
roundness: {
type: ROUNDNESS.PROPORTIONAL_RADIUS,
},
}),
pointFrom(-30, 0),
pointFrom(-25, 0),
).map((p) =>
pointFrom(Math.round(p[0] * 100) / 100, Math.round(p[1] * 100) / 100),
),
).toEqual([pointFrom(-17.93, 0), pointFrom(17.93, 0)]);
});
});

View file

@ -22,11 +22,7 @@ import {
isImageElement,
isTextElement,
} from "./typeChecks";
import {
getBoundTextShape,
getCornerRadius,
getDiamondPoints,
} from "../shapes";
import { getBoundTextShape, getCornerRadius } from "../shapes";
import type { Arc, GlobalPoint, Polygon } from "../../math";
import {
pathIsALoop,
@ -43,6 +39,7 @@ import {
pointDistanceSq,
ellipse,
ellipseLineIntersectionPoints,
pointsEqual,
} from "../../math";
import { LINE_CONFIRM_THRESHOLD } from "../constants";
@ -152,7 +149,7 @@ export const intersectElementWithLine = (
element: ExcalidrawElement,
a: GlobalPoint,
b: GlobalPoint,
offset: number,
offset: number = 0,
): GlobalPoint[] => {
switch (element.type) {
case "rectangle":
@ -172,7 +169,7 @@ export const intersectElementWithLine = (
}
};
export const intersectRectanguloidWithLine = (
const intersectRectanguloidWithLine = (
element: ExcalidrawRectanguloidElement,
a: GlobalPoint,
b: GlobalPoint,
@ -234,8 +231,8 @@ export const intersectRectanguloidWithLine = (
arc<GlobalPoint>(
pointFrom(r[0][0] + roundness, r[0][1] + roundness),
roundness,
radians(Math.PI),
radians((3 / 4) * Math.PI),
radians(0),
),
arc<GlobalPoint>(
pointFrom(r[1][0] - roundness, r[0][1] + roundness),
@ -261,8 +258,13 @@ export const intersectRectanguloidWithLine = (
.map((j) => pointRotateRads(j, center, element.angle))
: [];
return [...sideIntersections, ...cornerIntersections].sort(
(g, h) => pointDistanceSq(g!, b) - pointDistanceSq(h!, b),
return (
[...sideIntersections, ...cornerIntersections]
// Remove duplicates
.filter(
(p, idx, points) => points.findIndex((d) => pointsEqual(p, d)) === idx,
)
.sort((g, h) => pointDistanceSq(g!, b) - pointDistanceSq(h!, b))
);
};
@ -273,31 +275,39 @@ export const intersectRectanguloidWithLine = (
* @param b
* @returns
*/
export const intersectDiamondWithLine = (
const intersectDiamondWithLine = (
element: ExcalidrawDiamondElement,
a: GlobalPoint,
b: GlobalPoint,
offset: number = 0,
): GlobalPoint[] => {
const [topX, topY, rightX, rightY, bottomX, bottomY, leftX, leftY] =
getDiamondPoints(element, offset);
const center = pointFrom<GlobalPoint>(
(topX + bottomX) / 2,
(topY + bottomY) / 2,
const top = pointFrom<GlobalPoint>(element.x + element.width / 2, element.y);
const right = pointFrom<GlobalPoint>(
element.x + element.width,
element.y + element.height / 2,
);
const bottom = pointFrom<GlobalPoint>(
element.x + element.width / 2,
element.y + element.height,
);
const left = pointFrom<GlobalPoint>(
element.x,
element.y + element.height / 2,
);
const center = pointFrom<GlobalPoint>(
element.x + element.width / 2,
element.y + element.height / 2,
);
const verticalRadius = getCornerRadius(Math.abs(top[0] - left[0]), element);
const horizontalRadius = getCornerRadius(
Math.abs(right[1] - top[1]),
element,
);
const verticalRadius = getCornerRadius(Math.abs(topX - leftX), element);
const horizontalRadius = getCornerRadius(Math.abs(rightY - topY), element);
// Rotate the point to the inverse direction to simulate the rotated diamond
// points. It's all the same distance-wise.
const rotatedA = pointRotateRads(a, center, radians(-element.angle));
const rotatedB = pointRotateRads(b, center, radians(-element.angle));
const [top, right, bottom, left]: GlobalPoint[] = [
pointFrom(element.x + topX, element.y + topY),
pointFrom(element.x + rightX, element.y + rightY),
pointFrom(element.x + bottomX, element.y + bottomY),
pointFrom(element.x + leftX, element.y + leftY),
];
const topRight = createDiamondSide(
segment<GlobalPoint>(top, right),
@ -322,10 +332,42 @@ export const intersectDiamondWithLine = (
const arcs: Arc<GlobalPoint>[] = element.roundness
? [
createDiamondArc(topLeft[0], topRight[0], verticalRadius), // TOP
createDiamondArc(topRight[1], bottomRight[1], horizontalRadius), // RIGHT
createDiamondArc(bottomRight[0], bottomLeft[0], verticalRadius), // BOTTOM
createDiamondArc(bottomLeft[1], topLeft[1], horizontalRadius), // LEFT
createDiamondArc(
topLeft[0],
topRight[0],
pointFrom(
top[0],
top[1] + Math.sqrt(2 * Math.pow(verticalRadius, 2)),
),
verticalRadius,
), // TOP
createDiamondArc(
topRight[1],
bottomRight[1],
pointFrom(
right[0] - Math.sqrt(2 * Math.pow(horizontalRadius, 2)),
right[1],
),
horizontalRadius,
), // RIGHT
createDiamondArc(
bottomRight[0],
bottomLeft[0],
pointFrom(
bottom[0],
bottom[1] - Math.sqrt(2 * Math.pow(verticalRadius, 2)),
),
verticalRadius,
), // BOTTOM
createDiamondArc(
bottomLeft[1],
topLeft[1],
pointFrom(
left[0] + Math.sqrt(2 * Math.pow(horizontalRadius, 2)),
left[1],
),
horizontalRadius,
), // LEFT
]
: [];
@ -342,8 +384,13 @@ export const intersectDiamondWithLine = (
// Rotate back intersection points
.map((p) => pointRotateRads(p, center, element.angle));
return [...sides, ...corners].sort(
(g, h) => pointDistanceSq(g!, b) - pointDistanceSq(h!, b),
return (
[...sides, ...corners]
// Remove duplicates
.filter(
(p, idx, points) => points.findIndex((d) => pointsEqual(p, d)) === idx,
)
.sort((g, h) => pointDistanceSq(g!, b) - pointDistanceSq(h!, b))
);
};
@ -354,7 +401,7 @@ export const intersectDiamondWithLine = (
* @param b
* @returns
*/
export const intersectEllipseWithLine = (
const intersectEllipseWithLine = (
element: ExcalidrawEllipseElement,
a: GlobalPoint,
b: GlobalPoint,

View file

@ -172,10 +172,30 @@ export const distanceToDiamondElement = (
const arcs = element.roundness
? [
createDiamondArc(topLeft[0], topRight[0], verticalRadius), // TOP
createDiamondArc(topRight[1], bottomRight[1], horizontalRadius), // RIGHT
createDiamondArc(bottomRight[0], bottomLeft[0], verticalRadius), // BOTTOM
createDiamondArc(bottomLeft[1], topLeft[1], horizontalRadius), // LEFT
createDiamondArc(
topLeft[0],
topRight[0],
pointFrom(top[0], top[1] + verticalRadius),
verticalRadius,
), // TOP
createDiamondArc(
topRight[1],
bottomRight[1],
pointFrom(right[0] - horizontalRadius, right[1]),
horizontalRadius,
), // RIGHT
createDiamondArc(
bottomRight[0],
bottomLeft[0],
pointFrom(bottom[0], bottom[1] - verticalRadius),
verticalRadius,
), // BOTTOM
createDiamondArc(
bottomLeft[1],
topLeft[1],
pointFrom(right[0] + horizontalRadius, right[1]),
horizontalRadius,
), // LEFT
]
: [];

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@ -60,7 +60,8 @@ export const normalizeRadians = (angle: Radians): Radians => {
export const cartesian2Polar = <P extends GenericPoint>([
x,
y,
]: P): PolarCoords => polar(Math.hypot(x, y), radians(Math.atan2(y, x)));
]: P): PolarCoords =>
polar(Math.hypot(x, y), normalizeRadians(radians(Math.atan2(y, x))));
/**
* Convert an angle in degrees into randians

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@ -1,70 +0,0 @@
import * as GA from "./ga";
import { point, toString, direction, offset } from "./ga";
import * as GAPoint from "./gapoints";
import * as GALine from "./galines";
import * as GATransform from "./gatransforms";
describe("geometric algebra", () => {
describe("points", () => {
it("distanceToLine", () => {
const point = GA.point(3, 3);
const line = GALine.equation(0, 1, -1);
expect(GAPoint.distanceToLine(point, line)).toEqual(2);
});
it("distanceToLine neg", () => {
const point = GA.point(-3, -3);
const line = GALine.equation(0, 1, -1);
expect(GAPoint.distanceToLine(point, line)).toEqual(-4);
});
});
describe("lines", () => {
it("through", () => {
const a = GA.point(0, 0);
const b = GA.point(2, 0);
expect(toString(GALine.through(a, b))).toEqual(
toString(GALine.equation(0, 2, 0)),
);
});
it("parallel", () => {
const point = GA.point(3, 3);
const line = GALine.equation(0, 1, -1);
const parallel = GALine.parallel(line, 2);
expect(GAPoint.distanceToLine(point, parallel)).toEqual(0);
});
});
describe("translation", () => {
it("points", () => {
const start = point(2, 2);
const move = GATransform.translation(direction(0, 1));
const end = GATransform.apply(move, start);
expect(toString(end)).toEqual(toString(point(2, 3)));
});
it("points 2", () => {
const start = point(2, 2);
const move = GATransform.translation(offset(3, 4));
const end = GATransform.apply(move, start);
expect(toString(end)).toEqual(toString(point(5, 6)));
});
it("lines", () => {
const original = GALine.through(point(2, 2), point(3, 4));
const move = GATransform.translation(offset(3, 4));
const parallel = GATransform.apply(move, original);
expect(toString(parallel)).toEqual(
toString(GALine.through(point(5, 6), point(6, 8))),
);
});
});
describe("rotation", () => {
it("points", () => {
const start = point(2, 2);
const pivot = point(1, 1);
const rotate = GATransform.rotation(pivot, Math.PI / 2);
const end = GATransform.apply(rotate, start);
expect(toString(end)).toEqual(toString(point(2, 0)));
});
});
});

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@ -1,317 +0,0 @@
/**
* This is a 2D Projective Geometric Algebra implementation.
*
* For wider context on geometric algebra visit see https://bivector.net.
*
* For this specific algebra see cheatsheet https://bivector.net/2DPGA.pdf.
*
* Converted from generator written by enki, with a ton of added on top.
*
* This library uses 8-vectors to represent points, directions and lines
* in 2D space.
*
* An array `[a, b, c, d, e, f, g, h]` represents a n(8)vector:
* a + b*e0 + c*e1 + d*e2 + e*e01 + f*e20 + g*e12 + h*e012
*
* See GAPoint, GALine, GADirection and GATransform modules for common
* operations.
*/
export type Point = NVector;
export type Direction = NVector;
export type Line = NVector;
export type Transform = NVector;
export const point = (x: number, y: number): Point => [0, 0, 0, 0, y, x, 1, 0];
export const origin = (): Point => [0, 0, 0, 0, 0, 0, 1, 0];
export const direction = (x: number, y: number): Direction => {
const norm = Math.hypot(x, y); // same as `inorm(direction(x, y))`
return [0, 0, 0, 0, y / norm, x / norm, 0, 0];
};
export const offset = (x: number, y: number): Direction => [
0,
0,
0,
0,
y,
x,
0,
0,
];
/// This is the "implementation" part of the library
type NVector = readonly [
number,
number,
number,
number,
number,
number,
number,
number,
];
// These are labels for what each number in an nvector represents
const NVECTOR_BASE = ["1", "e0", "e1", "e2", "e01", "e20", "e12", "e012"];
// Used to represent points, lines and transformations
export const nvector = (value: number = 0, index: number = 0): NVector => {
const result = [0, 0, 0, 0, 0, 0, 0, 0];
if (index < 0 || index > 7) {
throw new Error(`Expected \`index\` between 0 and 7, got \`${index}\``);
}
if (value !== 0) {
result[index] = value;
}
return result as unknown as NVector;
};
const STRING_EPSILON = 0.000001;
export const toString = (nvector: NVector): string => {
const result = nvector
.map((value, index) =>
Math.abs(value) > STRING_EPSILON
? value.toFixed(7).replace(/(\.|0+)$/, "") +
(index > 0 ? NVECTOR_BASE[index] : "")
: null,
)
.filter((representation) => representation != null)
.join(" + ");
return result === "" ? "0" : result;
};
// Reverse the order of the basis blades.
export const reverse = (nvector: NVector): NVector => [
nvector[0],
nvector[1],
nvector[2],
nvector[3],
-nvector[4],
-nvector[5],
-nvector[6],
-nvector[7],
];
// Poincare duality operator.
export const dual = (nvector: NVector): NVector => [
nvector[7],
nvector[6],
nvector[5],
nvector[4],
nvector[3],
nvector[2],
nvector[1],
nvector[0],
];
// Clifford Conjugation
export const conjugate = (nvector: NVector): NVector => [
nvector[0],
-nvector[1],
-nvector[2],
-nvector[3],
-nvector[4],
-nvector[5],
-nvector[6],
nvector[7],
];
// Main involution
export const involute = (nvector: NVector): NVector => [
nvector[0],
-nvector[1],
-nvector[2],
-nvector[3],
nvector[4],
nvector[5],
nvector[6],
-nvector[7],
];
// Multivector addition
export const add = (a: NVector, b: NVector | number): NVector => {
if (isNumber(b)) {
return [a[0] + b, a[1], a[2], a[3], a[4], a[5], a[6], a[7]];
}
return [
a[0] + b[0],
a[1] + b[1],
a[2] + b[2],
a[3] + b[3],
a[4] + b[4],
a[5] + b[5],
a[6] + b[6],
a[7] + b[7],
];
};
// Multivector subtraction
export const sub = (a: NVector, b: NVector | number): NVector => {
if (isNumber(b)) {
return [a[0] - b, a[1], a[2], a[3], a[4], a[5], a[6], a[7]];
}
return [
a[0] - b[0],
a[1] - b[1],
a[2] - b[2],
a[3] - b[3],
a[4] - b[4],
a[5] - b[5],
a[6] - b[6],
a[7] - b[7],
];
};
// The geometric product.
export const mul = (a: NVector, b: NVector | number): NVector => {
if (isNumber(b)) {
return [
a[0] * b,
a[1] * b,
a[2] * b,
a[3] * b,
a[4] * b,
a[5] * b,
a[6] * b,
a[7] * b,
];
}
return [
mulScalar(a, b),
b[1] * a[0] +
b[0] * a[1] -
b[4] * a[2] +
b[5] * a[3] +
b[2] * a[4] -
b[3] * a[5] -
b[7] * a[6] -
b[6] * a[7],
b[2] * a[0] + b[0] * a[2] - b[6] * a[3] + b[3] * a[6],
b[3] * a[0] + b[6] * a[2] + b[0] * a[3] - b[2] * a[6],
b[4] * a[0] +
b[2] * a[1] -
b[1] * a[2] +
b[7] * a[3] +
b[0] * a[4] +
b[6] * a[5] -
b[5] * a[6] +
b[3] * a[7],
b[5] * a[0] -
b[3] * a[1] +
b[7] * a[2] +
b[1] * a[3] -
b[6] * a[4] +
b[0] * a[5] +
b[4] * a[6] +
b[2] * a[7],
b[6] * a[0] + b[3] * a[2] - b[2] * a[3] + b[0] * a[6],
b[7] * a[0] +
b[6] * a[1] +
b[5] * a[2] +
b[4] * a[3] +
b[3] * a[4] +
b[2] * a[5] +
b[1] * a[6] +
b[0] * a[7],
];
};
export const mulScalar = (a: NVector, b: NVector): number =>
b[0] * a[0] + b[2] * a[2] + b[3] * a[3] - b[6] * a[6];
// The outer/exterior/wedge product.
export const meet = (a: NVector, b: NVector): NVector => [
b[0] * a[0],
b[1] * a[0] + b[0] * a[1],
b[2] * a[0] + b[0] * a[2],
b[3] * a[0] + b[0] * a[3],
b[4] * a[0] + b[2] * a[1] - b[1] * a[2] + b[0] * a[4],
b[5] * a[0] - b[3] * a[1] + b[1] * a[3] + b[0] * a[5],
b[6] * a[0] + b[3] * a[2] - b[2] * a[3] + b[0] * a[6],
b[7] * a[0] +
b[6] * a[1] +
b[5] * a[2] +
b[4] * a[3] +
b[3] * a[4] +
b[2] * a[5] +
b[1] * a[6],
];
// The regressive product.
export const join = (a: NVector, b: NVector): NVector => [
joinScalar(a, b),
a[1] * b[7] + a[4] * b[5] - a[5] * b[4] + a[7] * b[1],
a[2] * b[7] - a[4] * b[6] + a[6] * b[4] + a[7] * b[2],
a[3] * b[7] + a[5] * b[6] - a[6] * b[5] + a[7] * b[3],
a[4] * b[7] + a[7] * b[4],
a[5] * b[7] + a[7] * b[5],
a[6] * b[7] + a[7] * b[6],
a[7] * b[7],
];
export const joinScalar = (a: NVector, b: NVector): number =>
a[0] * b[7] +
a[1] * b[6] +
a[2] * b[5] +
a[3] * b[4] +
a[4] * b[3] +
a[5] * b[2] +
a[6] * b[1] +
a[7] * b[0];
// The inner product.
export const dot = (a: NVector, b: NVector): NVector => [
b[0] * a[0] + b[2] * a[2] + b[3] * a[3] - b[6] * a[6],
b[1] * a[0] +
b[0] * a[1] -
b[4] * a[2] +
b[5] * a[3] +
b[2] * a[4] -
b[3] * a[5] -
b[7] * a[6] -
b[6] * a[7],
b[2] * a[0] + b[0] * a[2] - b[6] * a[3] + b[3] * a[6],
b[3] * a[0] + b[6] * a[2] + b[0] * a[3] - b[2] * a[6],
b[4] * a[0] + b[7] * a[3] + b[0] * a[4] + b[3] * a[7],
b[5] * a[0] + b[7] * a[2] + b[0] * a[5] + b[2] * a[7],
b[6] * a[0] + b[0] * a[6],
b[7] * a[0] + b[0] * a[7],
];
export const norm = (a: NVector): number =>
Math.sqrt(Math.abs(a[0] * a[0] - a[2] * a[2] - a[3] * a[3] + a[6] * a[6]));
export const inorm = (a: NVector): number =>
Math.sqrt(Math.abs(a[7] * a[7] - a[5] * a[5] - a[4] * a[4] + a[1] * a[1]));
export const normalized = (a: NVector): NVector => {
const n = norm(a);
if (n === 0 || n === 1) {
return a;
}
const sign = a[6] < 0 ? -1 : 1;
return mul(a, sign / n);
};
export const inormalized = (a: NVector): NVector => {
const n = inorm(a);
if (n === 0 || n === 1) {
return a;
}
return mul(a, 1 / n);
};
const isNumber = (a: any): a is number => typeof a === "number";
export const E0: NVector = nvector(1, 1);
export const E1: NVector = nvector(1, 2);
export const E2: NVector = nvector(1, 3);
export const E01: NVector = nvector(1, 4);
export const E20: NVector = nvector(1, 5);
export const E12: NVector = nvector(1, 6);
export const E012: NVector = nvector(1, 7);
export const I = E012;

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import * as GA from "./ga";
import type { Line, Direction, Point } from "./ga";
/**
* A direction is stored as an array `[0, 0, 0, 0, y, x, 0, 0]` representing
* vector `(x, y)`.
*/
export const from = (point: Point): Point => [
0,
0,
0,
0,
point[4],
point[5],
0,
0,
];
export const fromTo = (from: Point, to: Point): Direction =>
GA.inormalized([0, 0, 0, 0, to[4] - from[4], to[5] - from[5], 0, 0]);
export const orthogonal = (direction: Direction): Direction =>
GA.inormalized([0, 0, 0, 0, -direction[5], direction[4], 0, 0]);
export const orthogonalToLine = (line: Line): Direction => GA.mul(line, GA.I);

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import * as GA from "./ga";
import type { Line, Point } from "./ga";
/**
* A line is stored as an array `[0, c, a, b, 0, 0, 0, 0]` representing:
* c * e0 + a * e1 + b*e2
*
* This maps to a standard formula `a * x + b * y + c`.
*
* `(-b, a)` corresponds to a 2D vector parallel to the line. The lines
* have a natural orientation, corresponding to that vector.
*
* The magnitude ("norm") of the line is `sqrt(a ^ 2 + b ^ 2)`.
* `c / norm(line)` is the oriented distance from line to origin.
*/
// Returns line with direction (x, y) through origin
export const vector = (x: number, y: number): Line =>
GA.normalized([0, 0, -y, x, 0, 0, 0, 0]);
// For equation ax + by + c = 0.
export const equation = (a: number, b: number, c: number): Line =>
GA.normalized([0, c, a, b, 0, 0, 0, 0]);
export const through = (from: Point, to: Point): Line =>
GA.normalized(GA.join(to, from));
export const orthogonal = (line: Line, point: Point): Line =>
GA.dot(line, point);
// Returns a line perpendicular to the line through `against` and `intersection`
// going through `intersection`.
export const orthogonalThrough = (against: Point, intersection: Point): Line =>
orthogonal(through(against, intersection), intersection);
export const parallel = (line: Line, distance: number): Line => {
const result = line.slice();
result[1] -= distance;
return result as unknown as Line;
};
export const parallelThrough = (line: Line, point: Point): Line =>
orthogonal(orthogonal(point, line), point);
export const distance = (line1: Line, line2: Line): number =>
GA.inorm(GA.meet(line1, line2));
export const angle = (line1: Line, line2: Line): number =>
Math.acos(GA.dot(line1, line2)[0]);
// The orientation of the line
export const sign = (line: Line): number => Math.sign(line[1]);

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import * as GA from "./ga";
import * as GALine from "./galines";
import type { Point, Line } from "./ga";
import { join } from "./ga";
export const from = ([x, y]: readonly [number, number]): Point => [
0,
0,
0,
0,
y,
x,
1,
0,
];
export const toTuple = (point: Point): [number, number] => [point[5], point[4]];
export const abs = (point: Point): Point => [
0,
0,
0,
0,
Math.abs(point[4]),
Math.abs(point[5]),
1,
0,
];
export const intersect = (line1: Line, line2: Line): Point =>
GA.normalized(GA.meet(line1, line2));
// Projects `point` onto the `line`.
// The returned point is the closest point on the `line` to the `point`.
export const project = (point: Point, line: Line): Point =>
intersect(GALine.orthogonal(line, point), line);
export const distance = (point1: Point, point2: Point): number =>
GA.norm(join(point1, point2));
export const distanceToLine = (point: Point, line: Line): number =>
GA.joinScalar(point, line);

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import * as GA from "./ga";
import type { Line, Direction, Point, Transform } from "./ga";
import * as GADirection from "./gadirections";
/**
* TODO: docs
*/
export const rotation = (pivot: Point, angle: number): Transform =>
GA.add(GA.mul(pivot, Math.sin(angle / 2)), Math.cos(angle / 2));
export const translation = (direction: Direction): Transform => [
1,
0,
0,
0,
-(0.5 * direction[5]),
0.5 * direction[4],
0,
0,
];
export const translationOrthogonal = (
direction: Direction,
distance: number,
): Transform => {
const scale = 0.5 * distance;
return [1, 0, 0, 0, scale * direction[4], scale * direction[5], 0, 0];
};
export const translationAlong = (line: Line, distance: number): Transform =>
GA.add(GA.mul(GADirection.orthogonalToLine(line), 0.5 * distance), 1);
export const compose = (motor1: Transform, motor2: Transform): Transform =>
GA.mul(motor2, motor1);
export const apply = (
motor: Transform,
nvector: Point | Direction | Line,
): Point | Direction | Line =>
GA.normalized(GA.mul(GA.mul(motor, nvector), GA.reverse(motor)));