Function createPolygon

lib/offset-polygon.js:19–54

(vertices)

  };
}
function createPolygon(vertices) {
  const edges = [];
  let minX = vertices.length > 0 ? vertices[0].x : void 0;
  let minY = vertices.length > 0 ? vertices[0].y : void 0;
  let maxX = minX;
  let maxY = minY;
  for (let i = 0; i < vertices.length; i++) {
    const vertex1 = vertices[i];
    const vertex2 = vertices[(i + 1) % vertices.length];
    const outwardNormal = outwardEdgeNormal(vertex1, vertex2);
    const inwardNormal = inwardEdgeNormal(vertex1, vertex2);
    const edge = {
      vertex1,
      vertex2,
      index: i,
      outwardNormal,
      inwardNormal
    };
    edges.push(edge);
    const x = vertices[i].x;
    const y = vertices[i].y;
    minX = Math.min(x, minX);
    minY = Math.min(y, minY);
    maxX = Math.max(x, maxX);
    maxY = Math.max(y, maxY);
  }
  const polygon = {
    vertices,
    edges,
    minX,
    minY,
    maxX,
    maxY
  };
  return polygon;
}
function edgesIntersection(edgeA, edgeB) {
  const den = (edgeB.vertex2.y - edgeB.vertex1.y) * (edgeA.vertex2.x - edgeA.vertex1.x) - (edgeB.vertex2.x - edgeB.vertex1.x) * (edgeA.vertex2.y - edgeA.vertex1.y);
  if (den == 0) {