Mark Tolmacs 4ba1bdaead
State
2025-05-15 18:20:47 +02:00

99 lines
2.6 KiB
TypeScript

import { simplify } from "points-on-curve";
import {
polygonFromPoints,
lineSegment,
lineSegmentIntersectionPoints,
polygonIncludesPointNonZero,
} from "@excalidraw/math";
import type {
ElementsSegmentsMap,
GlobalPoint,
LineSegment,
} from "@excalidraw/math/types";
import type { ExcalidrawElement } from "@excalidraw/element/types";
import { intersectElementWithLineSegment } from "@excalidraw/element";
import App from "../components/App";
export const getLassoSelectedElementIds = (input: {
lassoPath: GlobalPoint[];
elements: readonly ExcalidrawElement[];
intersectedElements: Set<ExcalidrawElement["id"]>;
enclosedElements: Set<ExcalidrawElement["id"]>;
simplifyDistance?: number;
}): {
selectedElementIds: string[];
} => {
const {
lassoPath,
elements,
intersectedElements,
enclosedElements,
simplifyDistance,
} = input;
// simplify the path to reduce the number of points
let path: GlobalPoint[] = lassoPath;
if (simplifyDistance) {
path = simplify(lassoPath, simplifyDistance) as GlobalPoint[];
}
// as the path might not enclose a shape anymore, clear before checking
enclosedElements.clear();
for (const element of elements) {
if (
!intersectedElements.has(element.id) &&
!enclosedElements.has(element.id)
) {
const enclosed = enclosureTest(path, element, elementsSegments);
if (enclosed) {
enclosedElements.add(element.id);
} else {
const intersects = intersectionTest(path, element, app);
if (intersects) {
intersectedElements.add(element.id);
}
}
}
}
const results = [...intersectedElements, ...enclosedElements];
return {
selectedElementIds: results,
};
};
const enclosureTest = (
lassoPath: GlobalPoint[],
element: ExcalidrawElement,
app: App,
): boolean => {
const lassoSegments = lassoPath
.slice(1)
.map((point, index) => lineSegment(lassoPath[index], point))
.concat(lineSegment(lassoPath[lassoPath.length - 1], lassoPath[0]));
const offset = app.getElementHitThreshold();
return segments.some((segment) => {
return segment.some((point) =>
polygonIncludesPointNonZero(point, lassoPolygon),
);
});
};
const intersectionTest = (
lassoPath: GlobalPoint[],
element: ExcalidrawElement,
app: App,
): boolean => {
const lassoSegments = lassoPath
.slice(1)
.map((point, index) => lineSegment(lassoPath[index], point))
.concat(lineSegment(lassoPath[lassoPath.length - 1], lassoPath[0]));
const offset = app.getElementHitThreshold();
return lassoSegments.some((lassoSegment) =>
intersectElementWithLineSegment(element, lassoSegment, offset),
);
};