polygon.java

gcc的组建

   * @param y the Y coordinate of the point to test
   * @return true if the point is inside this polygon
   * @see #contains(double, double)
   * @since 1.1
   */
  public boolean contains(int x, int y)
  {
    return contains((double) x, (double) y);
  }

  /**
   * Tests whether or not the specified point is inside this polygon.
   *
   * @param x the X coordinate of the point to test
   * @param y the Y coordinate of the point to test
   * @return true if the point is inside this polygon
   * @see #contains(double, double)
   * @deprecated use {@link #contains(int, int)} instead
   */
  public boolean inside(int x, int y)
  {
    return contains((double) x, (double) y);
  }

  /**
   * Returns a high-precision bounding box of this polygon. This is the
   * smallest rectangle with sides parallel to the X axis that will contain
   * this polygon.
   *
   * @return the bounding box for this polygon
   * @see #getBounds()
   * @since 1.2
   */
  public Rectangle2D getBounds2D()
  {
    // For polygons, the integer version is exact!
    return getBounds();
  }

  /**
   * Tests whether or not the specified point is inside this polygon.
   *
   * @param x the X coordinate of the point to test
   * @param y the Y coordinate of the point to test
   * @return true if the point is inside this polygon
   * @since 1.2
   */
  public boolean contains(double x, double y)
  {
    return ((evaluateCrossings(x, y, false, BIG_VALUE) & 1) != 0);
  }

  /**
   * Tests whether or not the specified point is inside this polygon.
   *
   * @param p the point to test
   * @return true if the point is inside this polygon
   * @throws NullPointerException if p is null
   * @see #contains(double, double)
   * @since 1.2
   */
  public boolean contains(Point2D p)
  {
    return contains(p.getX(), p.getY());
  }

  /**
   * Test if a high-precision rectangle intersects the shape. This is true
   * if any point in the rectangle is in the shape. This implementation is
   * precise.
   *
   * @param x the x coordinate of the rectangle
   * @param y the y coordinate of the rectangle
   * @param w the width of the rectangle, treated as point if negative
   * @param h the height of the rectangle, treated as point if negative
   * @return true if the rectangle intersects this shape
   * @since 1.2
   */
  public boolean intersects(double x, double y, double w, double h)
  {
    /* Does any edge intersect? */
    if (evaluateCrossings(x, y, false, w) != 0 /* top */
        || evaluateCrossings(x, y + h, false, w) != 0 /* bottom */
        || evaluateCrossings(x + w, y, true, h) != 0 /* right */
        || evaluateCrossings(x, y, true, h) != 0) /* left */
      return true;

    /* No intersections, is any point inside? */
    if ((evaluateCrossings(x, y, false, BIG_VALUE) & 1) != 0)
      return true;

    return false;
  }

  /**
   * Test if a high-precision rectangle intersects the shape. This is true
   * if any point in the rectangle is in the shape. This implementation is
   * precise.
   *
   * @param r the rectangle
   * @return true if the rectangle intersects this shape
   * @throws NullPointerException if r is null
   * @see #intersects(double, double, double, double)
   * @since 1.2
   */
  public boolean intersects(Rectangle2D r)
  {
    return intersects(r.getX(), r.getY(), r.getWidth(), r.getHeight());
  }

  /**
   * Test if a high-precision rectangle lies completely in the shape. This is
   * true if all points in the rectangle are in the shape. This implementation
   * is precise.
   *
   * @param x the x coordinate of the rectangle
   * @param y the y coordinate of the rectangle
   * @param w the width of the rectangle, treated as point if negative
   * @param h the height of the rectangle, treated as point if negative
   * @return true if the rectangle is contained in this shape
   * @since 1.2
   */
  public boolean contains(double x, double y, double w, double h)
  {
    if (! getBounds2D().intersects(x, y, w, h))
      return false;

    /* Does any edge intersect? */
    if (evaluateCrossings(x, y, false, w) != 0 /* top */
        || evaluateCrossings(x, y + h, false, w) != 0 /* bottom */
        || evaluateCrossings(x + w, y, true, h) != 0 /* right */
        || evaluateCrossings(x, y, true, h) != 0) /* left */
      return false;

    /* No intersections, is any point inside? */
    if ((evaluateCrossings(x, y, false, BIG_VALUE) & 1) != 0)
      return true;

    return false;
  }

  /**
   * Test if a high-precision rectangle lies completely in the shape. This is
   * true if all points in the rectangle are in the shape. This implementation
   * is precise.
   *
   * @param r the rectangle
   * @return true if the rectangle is contained in this shape
   * @throws NullPointerException if r is null
   * @see #contains(double, double, double, double)
   * @since 1.2
   */
  public boolean contains(Rectangle2D r)
  {
    return contains(r.getX(), r.getY(), r.getWidth(), r.getHeight());
  }

  /**
   * Return an iterator along the shape boundary. If the optional transform
   * is provided, the iterator is transformed accordingly. Each call returns
   * a new object, independent from others in use. This class is not
   * threadsafe to begin with, so the path iterator is not either.
   *
   * @param transform an optional transform to apply to the iterator
   * @return a new iterator over the boundary
   * @since 1.2
   */
  public PathIterator getPathIterator(final AffineTransform transform)
  {
    return new PathIterator()
      {
	/** The current vertex of iteration. */
	private int vertex;

	public int getWindingRule()
	{
	  return WIND_EVEN_ODD;
	}

	public boolean isDone()
	{
	  return vertex > npoints;
	}

	public void next()
	{
	  vertex++;
	}

	public int currentSegment(float[] coords)
	{
	  if (vertex >= npoints)
	    return SEG_CLOSE;
	  coords[0] = xpoints[vertex];
	  coords[1] = ypoints[vertex];
	  if (transform != null)
	    transform.transform(coords, 0, coords, 0, 1);
	  return vertex == 0 ? SEG_MOVETO : SEG_LINETO;
	}

	public int currentSegment(double[] coords)
	{
	  if (vertex >= npoints)
	    return SEG_CLOSE;
	  coords[0] = xpoints[vertex];
	  coords[1] = ypoints[vertex];
	  if (transform != null)
	    transform.transform(coords, 0, coords, 0, 1);
	  return vertex == 0 ? SEG_MOVETO : SEG_LINETO;
	}
      };
  }

  /**
   * Return an iterator along the flattened version of the shape boundary.
   * Since polygons are already flat, the flatness parameter is ignored, and
   * the resulting iterator only has SEG_MOVETO, SEG_LINETO and SEG_CLOSE
   * points. If the optional transform is provided, the iterator is
   * transformed accordingly. Each call returns a new object, independent
   * from others in use. This class is not threadsafe to begin with, so the
   * path iterator is not either.
   *
   * @param transform an optional transform to apply to the iterator
   * @param flatness the maximum distance for deviation from the real boundary
   * @return a new iterator over the boundary
   * @since 1.2
   */
  public PathIterator getPathIterator(AffineTransform transform,
                                      double flatness)
  {
    return getPathIterator(transform);
  }

  /**
   * Helper for contains, intersects, calculates the number of intersections
   * between the polygon and a line extending from the point (x, y) along
   * the positive X, or Y axis, within a given interval.
   *
   * @return the winding number.
   * @see #contains(double, double)
   */
  private int evaluateCrossings(double x, double y, boolean useYaxis,
                                double distance)
  {
    double x0;
    double x1;
    double y0;
    double y1;
    double epsilon = 0.0;
    int crossings = 0;
    int[] xp;
    int[] yp;

    if (useYaxis)
      {
	xp = ypoints;
	yp = xpoints;
	double swap;
	swap = y;
	y = x;
	x = swap;
      }
    else
      {
	xp = xpoints;
	yp = ypoints;
      }

    /* Get a value which is small but not insignificant relative the path. */
    epsilon = 1E-7;

    x0 = xp[0] - x;
    y0 = yp[0] - y;
    for (int i = 1; i < npoints; i++)
      {
	x1 = xp[i] - x;
	y1 = yp[i] - y;

	if (y0 == 0.0)
	  y0 -= epsilon;
	if (y1 == 0.0)
	  y1 -= epsilon;
	if (y0 * y1 < 0)
	  if (Line2D.linesIntersect(x0, y0, x1, y1, epsilon, 0.0, distance, 0.0))
	    ++crossings;

	x0 = xp[i] - x;
	y0 = yp[i] - y;
      }

    // end segment
    x1 = xp[0] - x;
    y1 = yp[0] - y;
    if (y0 == 0.0)
      y0 -= epsilon;
    if (y1 == 0.0)
      y1 -= epsilon;
    if (y0 * y1 < 0)
      if (Line2D.linesIntersect(x0, y0, x1, y1, epsilon, 0.0, distance, 0.0))
	++crossings;

    return crossings;
  }
} // class Polygon