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- /**
- * @typedef {import('diagram-js/lib/util/Types').Point} Point
- */
- /**
- * Returns the intersection between two line segments a and b.
- *
- * @param {Point} l1s
- * @param {Point} l1e
- * @param {Point} l2s
- * @param {Point} l2e
- *
- * @return {Point}
- */
- export default function lineIntersect(l1s, l1e, l2s, l2e) {
- // if the lines intersect, the result contains the x and y of the
- // intersection (treating the lines as infinite) and booleans for
- // whether line segment 1 or line segment 2 contain the point
- var denominator, a, b, c, numerator;
- denominator = ((l2e.y - l2s.y) * (l1e.x - l1s.x)) - ((l2e.x - l2s.x) * (l1e.y - l1s.y));
- if (denominator == 0) {
- return null;
- }
- a = l1s.y - l2s.y;
- b = l1s.x - l2s.x;
- numerator = ((l2e.x - l2s.x) * a) - ((l2e.y - l2s.y) * b);
- c = numerator / denominator;
- // if we cast these lines infinitely in
- // both directions, they intersect here
- return {
- x: Math.round(l1s.x + (c * (l1e.x - l1s.x))),
- y: Math.round(l1s.y + (c * (l1e.y - l1s.y)))
- };
- }
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