@antv/path-util/esm/is-polygons-intersect.js

A common util collection for antv projects

import isPointInPolygon from './point-in-polygon';
import getLineIntersect from './get-line-intersect';
import { each } from 'lodash-es';
function parseToLines(points) {
    var lines = [];
    var count = points.length;
    for (var i = 0; i < count - 1; i++) {
        var point = points[i];
        var next = points[i + 1];
        lines.push({
            from: {
                x: point[0],
                y: point[1],
            },
            to: {
                x: next[0],
                y: next[1],
            },
        });
    }
    if (lines.length > 1) {
        var first = points[0];
        var last = points[count - 1];
        lines.push({
            from: {
                x: last[0],
                y: last[1],
            },
            to: {
                x: first[0],
                y: first[1],
            },
        });
    }
    return lines;
}
function lineIntersectPolygon(lines, line) {
    var isIntersect = false;
    each(lines, function (l) {
        if (getLineIntersect(l.from, l.to, line.from, line.to)) {
            isIntersect = true;
            return false;
        }
    });
    return isIntersect;
}
function getBBox(points) {
    var xArr = points.map(function (p) { return p[0]; });
    var yArr = points.map(function (p) { return p[1]; });
    return {
        minX: Math.min.apply(null, xArr),
        maxX: Math.max.apply(null, xArr),
        minY: Math.min.apply(null, yArr),
        maxY: Math.max.apply(null, yArr),
    };
}
function intersectBBox(box1, box2) {
    return !(box2.minX > box1.maxX || box2.maxX < box1.minX || box2.minY > box1.maxY || box2.maxY < box1.minY);
}
export default function isPolygonsIntersect(points1, points2) {
    // 空数组，或者一个点返回 false
    if (points1.length < 2 || points2.length < 2) {
        return false;
    }
    var bbox1 = getBBox(points1);
    var bbox2 = getBBox(points2);
    // 判定包围盒是否相交，比判定点是否在多边形内要快的多，可以筛选掉大多数情况
    if (!intersectBBox(bbox1, bbox2)) {
        return false;
    }
    var isIn = false;
    // 判定点是否在多边形内部，一旦有一个点在另一个多边形内，则返回
    each(points2, function (point) {
        if (isPointInPolygon(points1, point[0], point[1])) {
            isIn = true;
            return false;
        }
    });
    if (isIn) {
        return true;
    }
    // 两个多边形都需要判定
    each(points1, function (point) {
        if (isPointInPolygon(points2, point[0], point[1])) {
            isIn = true;
            return false;
        }
    });
    if (isIn) {
        return true;
    }
    var lines1 = parseToLines(points1);
    var lines2 = parseToLines(points2);
    var isIntersect = false;
    each(lines2, function (line) {
        if (lineIntersectPolygon(lines1, line)) {
            isIntersect = true;
            return false;
        }
    });
    return isIntersect;
}
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