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Inverted polygon now works just as well for hit testing

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Signed-off-by: Mark Tolmacs <mark@lazycat.hu>
This commit is contained in:
Mark Tolmacs 2025-05-09 21:25:35 +02:00
parent e1b81480ac
commit d08414c2a9
No known key found for this signature in database
6 changed files with 136 additions and 197 deletions
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102
packages/element/src/Shape.ts
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@ -1,10 +1,17 @@
import { simplify } from "points-on-curve";
import { pointFrom, pointDistance, type LocalPoint } from "@excalidraw/math";
import {
pointFrom,
pointDistance,
type LocalPoint,
pointRotateRads,
} from "@excalidraw/math";
import { ROUGHNESS, isTransparent, assertNever } from "@excalidraw/common";
import { RoughGenerator } from "roughjs/bin/generator";
import type { GlobalPoint, Radians } from "@excalidraw/math";
import type { Mutable } from "@excalidraw/common/utility-types";
import type { EmbedsValidationStatus } from "@excalidraw/excalidraw/types";
@ -22,7 +29,11 @@ import { headingForPointIsHorizontal } from "./heading";
import { canChangeRoundness } from "./comparisons";
import { generateFreeDrawShape } from "./renderElement";
import { getArrowheadPoints, getDiamondPoints } from "./bounds";
import {
getArrowheadPoints,
getDiamondPoints,
getElementBounds,
} from "./bounds";
import type {
ExcalidrawElement,
@ -320,33 +331,92 @@ export const generateLinearCollisionShape = (
switch (element.type) {
case "line":
case "arrow": {
let shape: any;
// points array can be empty in the beginning, so it is important to add
// initial position to it
const points = element.points.length
? element.points
: [pointFrom<LocalPoint>(0, 0)];
const [x1, y1, x2, y2] = getElementBounds(
{
...element,
angle: 0 as Radians,
},
new Map(),
);
const center = pointFrom<GlobalPoint>((x1 + x2) / 2, (y1 + y2) / 2);
if (isElbowArrow(element)) {
shape = generator.path(generateElbowArrowShape(points, 16), options)
return generator.path(generateElbowArrowShape(points, 16), options)
.sets[0].ops;
} else if (!element.roundness) {
shape = points.map((point, idx) => {
return idx === 0
? { op: "move", data: point }
: {
op: "lineTo",
data: [point[0], point[1]],
return points.map((point, idx) => {
const p = pointRotateRads(
pointFrom<GlobalPoint>(element.x + point[0], element.y + point[1]),
center,
element.angle,
);
return {
op: idx === 0 ? "move" : "lineTo",
data: pointFrom<LocalPoint>(p[0] - element.x, p[1] - element.y),
};
});
} else {
shape = generator
.curve(points as unknown as RoughPoint[], options)
.sets[0].ops.slice(0, element.points.length);
}
return shape;
return generator
.curve(points as unknown as RoughPoint[], options)
.sets[0].ops.slice(0, element.points.length)
.map((op, i, arr) => {
if (i === 0) {
const p = pointRotateRads<GlobalPoint>(
pointFrom<GlobalPoint>(
element.x + op.data[0],
element.y + op.data[1],
),
center,
element.angle,
);
return {
op: "move",
data: pointFrom<LocalPoint>(p[0] - element.x, p[1] - element.y),
};
}
return {
op: "bcurveTo",
data: [
pointRotateRads(
pointFrom<GlobalPoint>(
element.x + op.data[0],
element.y + op.data[1],
),
center,
element.angle,
),
pointRotateRads(
pointFrom<GlobalPoint>(
element.x + op.data[2],
element.y + op.data[3],
),
center,
element.angle,
),
pointRotateRads(
pointFrom<GlobalPoint>(
element.x + op.data[4],
element.y + op.data[5],
),
center,
element.angle,
),
]
.map((p) =>
pointFrom<LocalPoint>(p[0] - element.x, p[1] - element.y),
)
.flat(),
};
});
}
case "freedraw": {
const simplifiedPoints = simplify(

49
packages/element/src/collision.ts
View File

@ -11,8 +11,12 @@ import {
lineSegment,
lineSegmentIntersectionPoints,
pointFrom,
pointFromVector,
pointRotateRads,
pointsEqual,
vectorFromPoint,
vectorNormalize,
vectorScale,
} from "@excalidraw/math";
import {
@ -20,8 +24,6 @@ import {
ellipseSegmentInterceptPoints,
} from "@excalidraw/math/ellipse";
import { isPointInShape, isPointOnShape } from "@excalidraw/utils/collision";
import type {
Curve,
GlobalPoint,
@ -35,6 +37,7 @@ import { isPathALoop } from "./shapes";
import { getElementBounds } from "./bounds";
import {
hasBoundTextElement,
isFreeDrawElement,
isIframeLikeElement,
isImageElement,
isLinearElement,
@ -50,6 +53,8 @@ import { getBoundTextElement } from "./textElement";
import { LinearElementEditor } from "./linearElementEditor";
import { distanceToElement } from "./distance";
import type {
ElementsMap,
ExcalidrawDiamondElement,
@ -219,11 +224,13 @@ const intersectLinearOrFreeDrawWithLineSegment = (
for (const shape of shapes) {
switch (true) {
case isCurve(shape):
//debugDrawCubicBezier(shape);
intersections.push(
...curveIntersectLineSegment(shape as Curve<GlobalPoint>, segment),
);
continue;
case isLineSegment(shape):
//debugDrawLine(shape);
const point = lineSegmentIntersectionPoints(
segment,
shape as LineSegment<GlobalPoint>,
@ -362,3 +369,41 @@ const intersectEllipseWithLineSegment = (
lineSegment(rotatedA, rotatedB),
).map((p) => pointRotateRads(p, center, element.angle));
};
// check if the given point is considered on the given shape's border
const isPointOnShape = (
point: GlobalPoint,
element: ExcalidrawElement,
tolerance = 1,
) => distanceToElement(element, point) <= tolerance;
// check if the given point is considered inside the element's border
export const isPointInShape = (
point: GlobalPoint,
element: ExcalidrawElement,
) => {
if (
(isLinearElement(element) || isFreeDrawElement(element)) &&
!isPathALoop(element.points)
) {
// There isn't any "inside" for a non-looping path
return false;
}
const [x1, y1, x2, y2] = getElementBounds(element, new Map());
const center = pointFrom<GlobalPoint>((x1 + x2) / 2, (y1 + y2) / 2);
const otherPoint = pointFromVector(
vectorScale(
vectorNormalize(vectorFromPoint(point, center, 0.1)),
Math.max(element.width, element.height) * 2,
),
center,
);
const intersector = lineSegment(point, otherPoint);
const intersections = intersectElementWithLineSegment(
element,
intersector,
).filter((item, pos, arr) => arr.indexOf(item) === pos);
return intersections.length % 2 === 1;
};

2
packages/excalidraw/components/App.tsx
View File

@ -17,7 +17,7 @@ import {
vectorDot,
vectorNormalize,
} from "@excalidraw/math";
import { isPointInShape } from "@excalidraw/utils/collision";
import { isPointInShape } from "@excalidraw/element/collision";
import {
COLOR_PALETTE,

3
packages/excalidraw/eraser/index.ts
View File

@ -1,5 +1,5 @@
import { arrayToMap, easeOut, THEME } from "@excalidraw/common";
import { getElementLineSegments } from "@excalidraw/element";
import { getElementLineSegments, isPointInShape } from "@excalidraw/element";
import {
lineSegment,
lineSegmentIntersectionPoints,
@ -9,7 +9,6 @@ import {
import { getElementsInGroup } from "@excalidraw/element";
import { shouldTestInside } from "@excalidraw/element";
import { isPointInShape } from "@excalidraw/utils/collision";
import { hasBoundTextElement, isBoundToContainer } from "@excalidraw/element";
import { getBoundTextElementId } from "@excalidraw/element";

85
packages/utils/src/collision.ts
View File

@ -1,85 +0,0 @@
import {
lineSegment,
pointFrom,
type GlobalPoint,
vectorFromPoint,
vectorNormalize,
vectorScale,
pointFromVector,
} from "@excalidraw/math";
import { intersectElementWithLineSegment } from "@excalidraw/element/collision";
import { elementCenterPoint } from "@excalidraw/common";
import { distanceToElement } from "@excalidraw/element/distance";
import { getCommonBounds, isLinearElement } from "@excalidraw/excalidraw";
import { isFreeDrawElement } from "@excalidraw/element/typeChecks";
import { isPathALoop } from "@excalidraw/element/shapes";
import {
debugDrawLine,
debugDrawPoint,
} from "@excalidraw/excalidraw/visualdebug";
import type { ExcalidrawElement } from "@excalidraw/element/types";
// check if the given point is considered on the given shape's border
export const isPointOnShape = (
point: GlobalPoint,
element: ExcalidrawElement,
tolerance = 1,
) => {
const distance = distanceToElement(element, point);
return distance <= tolerance;
};
// check if the given point is considered inside the element's border
export const isPointInShape = (
point: GlobalPoint,
element: ExcalidrawElement,
) => {
if (isLinearElement(element) || isFreeDrawElement(element)) {
if (isPathALoop(element.points)) {
const [minX, minY, maxX, maxY] = getCommonBounds([element]);
const center = pointFrom<GlobalPoint>(
(maxX + minX) / 2,
(maxY + minY) / 2,
);
const otherPoint = pointFromVector(
vectorScale(
vectorNormalize(vectorFromPoint(point, center, 0.1)),
Math.max(element.width, element.height) * 2,
),
center,
);
const intersector = lineSegment(point, otherPoint);
// What about being on the center exactly?
const intersections = intersectElementWithLineSegment(
element,
intersector,
);
const hit = intersections.length % 2 === 1;
debugDrawLine(intersector, { color: hit ? "green" : "red" });
debugDrawPoint(point, { color: "black" });
debugDrawPoint(otherPoint, { color: "blue" });
return hit;
}
// There isn't any "inside" for a non-looping path
return false;
}
const intersections = intersectElementWithLineSegment(
element,
lineSegment(elementCenterPoint(element), point),
);
return intersections.length === 0;
};

90
packages/utils/tests/collision.test.ts
View File

@ -1,90 +0,0 @@
import {
curve,
degreesToRadians,
lineSegment,
lineSegmentRotate,
pointFrom,
pointRotateDegs,
} from "@excalidraw/math";
import type { Curve, Degrees, GlobalPoint } from "@excalidraw/math";
import { pointOnCurve, pointOnPolyline } from "../src/collision";
import type { Polyline } from "../src/shape";
describe("point and curve", () => {
const c: Curve<GlobalPoint> = curve(
pointFrom(1.4, 1.65),
pointFrom(1.9, 7.9),
pointFrom(5.9, 1.65),
pointFrom(6.44, 4.84),
);
it("point on curve", () => {
expect(pointOnCurve(c[0], c, 10e-5)).toBe(true);
expect(pointOnCurve(c[3], c, 10e-5)).toBe(true);
expect(pointOnCurve(pointFrom(2, 4), c, 0.1)).toBe(true);
expect(pointOnCurve(pointFrom(4, 4.4), c, 0.1)).toBe(true);
expect(pointOnCurve(pointFrom(5.6, 3.85), c, 0.1)).toBe(true);
expect(pointOnCurve(pointFrom(5.6, 4), c, 0.1)).toBe(false);
expect(pointOnCurve(c[1], c, 0.1)).toBe(false);
expect(pointOnCurve(c[2], c, 0.1)).toBe(false);
});
});
describe("point and polylines", () => {
const polyline: Polyline<GlobalPoint> = [
lineSegment(pointFrom(1, 0), pointFrom(1, 2)),
lineSegment(pointFrom(1, 2), pointFrom(2, 2)),
lineSegment(pointFrom(2, 2), pointFrom(2, 1)),
lineSegment(pointFrom(2, 1), pointFrom(3, 1)),
];
it("point on the line", () => {
expect(pointOnPolyline(pointFrom(1, 0), polyline)).toBe(true);
expect(pointOnPolyline(pointFrom(1, 2), polyline)).toBe(true);
expect(pointOnPolyline(pointFrom(2, 2), polyline)).toBe(true);
expect(pointOnPolyline(pointFrom(2, 1), polyline)).toBe(true);
expect(pointOnPolyline(pointFrom(3, 1), polyline)).toBe(true);
expect(pointOnPolyline(pointFrom(1, 1), polyline)).toBe(true);
expect(pointOnPolyline(pointFrom(2, 1.5), polyline)).toBe(true);
expect(pointOnPolyline(pointFrom(2.5, 1), polyline)).toBe(true);
expect(pointOnPolyline(pointFrom(0, 1), polyline)).toBe(false);
expect(pointOnPolyline(pointFrom(2.1, 1.5), polyline)).toBe(false);
});
it("point on the line with rotation", () => {
const truePoints = [
pointFrom(1, 0),
pointFrom(1, 2),
pointFrom(2, 2),
pointFrom(2, 1),
pointFrom(3, 1),
];
truePoints.forEach((p) => {
const rotation = (Math.random() * 360) as Degrees;
const rotatedPoint = pointRotateDegs(p, pointFrom(0, 0), rotation);
const rotatedPolyline = polyline.map((line) =>
lineSegmentRotate(line, degreesToRadians(rotation), pointFrom(0, 0)),
);
expect(pointOnPolyline(rotatedPoint, rotatedPolyline)).toBe(true);
});
const falsePoints = [pointFrom(0, 1), pointFrom(2.1, 1.5)];
falsePoints.forEach((p) => {
const rotation = (Math.random() * 360) as Degrees;
const rotatedPoint = pointRotateDegs(p, pointFrom(0, 0), rotation);
const rotatedPolyline = polyline.map((line) =>
lineSegmentRotate(line, degreesToRadians(rotation), pointFrom(0, 0)),
);
expect(pointOnPolyline(rotatedPoint, rotatedPolyline)).toBe(false);
});
});
});