java - 如何将 Line2D 与 Java 中的区域相交？

Question

我有一个 Line2D 和一个 Area 对象，我想要相交的 Line2D。结果也可以是 GeneralPath。我怎样才能做到这一点？

Answer 1

您可以在类 Area中使用方法instersects 。不过 Line2D 可以用 Rectangle2D 代替。

Answer 2

Second chance :

• build your line2D, it is a shape.
• Build an area around it (using new Area( line2d ) );
• take the first area and call intersect with the second area obtained from the line.
• your first area is now the intersection of the first.
• take your leftmost, topmost, bottomost, rightmost coordinates
• turn them into a line2d

and here you are.

Answer 3

选项 1，用三角形近似 Line2D：

    Polygon polygon = new Polygon(new int[]{x1, x2, x2}, new int[]{y1, y2+e, y2-e}, 3);
    Area triangle = new Area(polygon);
    triangle.intersect(area); // intersection of ray and area
    return !triangle.isEmpty(); // returns true if intersects

选项 2，改用 Geometry 类

  private final GeometryFactory geometryFactory = new GeometryFactory();
  private ShapeReader shapeReader = new ShapeReader(geometryFactory);

  Path2D.Double thePath = new Path2D.Double(area);
  Geometry geometry  = shapeReader.read(thePath.getPathIterator(null));

  Coordinate[] coordinate = new Coordinate[] {new Coordinate(x1, y1), new Coordinate(x2, y2)};
  LineString centerRay = geometryFactory.createLineString(coordinate);

  return geometry.intersects(centerRay); // returns true if intersects