@rxflow/manhattan/esm/geometry/collision.js

Manhattan routing algorithm for ReactFlow - generates orthogonal paths with obstacle avoidance

import { Point } from "./Point";
/**
 * Check if a line segment intersects with a rectangle
 */
export function lineSegmentIntersectsRect(p1, p2, rect) {
  // Check if either endpoint is inside the rectangle
  if (rect.containsPoint(p1) || rect.containsPoint(p2)) {
    return true;
  }

  // Check if line segment intersects any of the rectangle's edges
  var rectPoints = [new Point(rect.x, rect.y), new Point(rect.x + rect.width, rect.y), new Point(rect.x + rect.width, rect.y + rect.height), new Point(rect.x, rect.y + rect.height)];
  for (var i = 0; i < 4; i++) {
    var r1 = rectPoints[i];
    var r2 = rectPoints[(i + 1) % 4];
    if (lineSegmentsIntersect(p1, p2, r1, r2)) {
      return true;
    }
  }
  return false;
}

/**
 * Check if a line segment crosses through a rectangle (not just touching edges)
 */
export function lineSegmentCrossesRect(p1, p2, rect) {
  var tolerance = 1;

  // Check if segment passes through the interior of the rectangle
  // We sample points along the segment and check if any are strictly inside
  var steps = 10;
  for (var i = 1; i < steps; i++) {
    var t = i / steps;
    var x = p1.x + (p2.x - p1.x) * t;
    var y = p1.y + (p2.y - p1.y) * t;
    if (x > rect.x + tolerance && x < rect.x + rect.width - tolerance && y > rect.y + tolerance && y < rect.y + rect.height - tolerance) {
      return true;
    }
  }
  return false;
}

/**
 * Check if two line segments intersect
 */
export function lineSegmentsIntersect(p1, p2, p3, p4) {
  var d1 = direction(p3, p4, p1);
  var d2 = direction(p3, p4, p2);
  var d3 = direction(p1, p2, p3);
  var d4 = direction(p1, p2, p4);
  if ((d1 > 0 && d2 < 0 || d1 < 0 && d2 > 0) && (d3 > 0 && d4 < 0 || d3 < 0 && d4 > 0)) {
    return true;
  }
  if (d1 === 0 && onSegment(p3, p1, p4)) return true;
  if (d2 === 0 && onSegment(p3, p2, p4)) return true;
  if (d3 === 0 && onSegment(p1, p3, p2)) return true;
  if (d4 === 0 && onSegment(p1, p4, p2)) return true;
  return false;
}

/**
 * Calculate direction of point p3 relative to line p1-p2
 */
function direction(p1, p2, p3) {
  return (p3.x - p1.x) * (p2.y - p1.y) - (p2.x - p1.x) * (p3.y - p1.y);
}

/**
 * Check if point p2 is on line segment p1-p3
 */
function onSegment(p1, p2, p3) {
  return p2.x >= Math.min(p1.x, p3.x) && p2.x <= Math.max(p1.x, p3.x) && p2.y >= Math.min(p1.y, p3.y) && p2.y <= Math.max(p1.y, p3.y);
}