quadcurve2d.java

gcc的组建

	if (t >= 0.0 && t <= 1.0)
	  {
	    double crossing = t * t * (b2 - 2 * b1 + b0) + 2 * t * (b1 - b0)
	                      + b0;
	    /* single root is always doubly degenerate in quads */
	    if (crossing > 0 && crossing < distance)
	      nCrossings += (nRoots == 1) ? 2 : 1;
	  }
      }

    if (useYaxis)
      {
	if (Line2D.linesIntersect(b0, a0, b2, a2, EPSILON, 0.0, distance, 0.0))
	  nCrossings++;
      }
    else
      {
	if (Line2D.linesIntersect(a0, b0, a2, b2, 0.0, EPSILON, 0.0, distance))
	  nCrossings++;
      }

    return (nCrossings);
  }

  /**
   * A two-dimensional curve that is parameterized with a quadratic
   * function and stores coordinate values in double-precision
   * floating-point format.
   *
   * @see QuadCurve2D.Float
   *
   * @author Eric Blake ([e-mail])
   * @author Sascha Brawer ([e-mail])
   */
  public static class Double extends QuadCurve2D
  {
    /**
     * The <i>x</i> coordinate of the curve&#x2019;s start point.
     */
    public double x1;

    /**
     * The <i>y</i> coordinate of the curve&#x2019;s start point.
     */
    public double y1;

    /**
     * The <i>x</i> coordinate of the curve&#x2019;s control point.
     */
    public double ctrlx;

    /**
     * The <i>y</i> coordinate of the curve&#x2019;s control point.
     */
    public double ctrly;

    /**
     * The <i>x</i> coordinate of the curve&#x2019;s end point.
     */
    public double x2;

    /**
     * The <i>y</i> coordinate of the curve&#x2019;s end point.
     */
    public double y2;

    /**
     * Constructs a new QuadCurve2D that stores its coordinate values
     * in double-precision floating-point format. All points are
     * initially at position (0, 0).
     */
    public Double()
    {
    }

    /**
     * Constructs a new QuadCurve2D that stores its coordinate values
     * in double-precision floating-point format, specifying the
     * initial position of each point.
     *
     * @param x1 the <i>x</i> coordinate of the curve&#x2019;s start
     * point.
     *
     * @param y1 the <i>y</i> coordinate of the curve&#x2019;s start
     * point.
     *
     * @param cx the <i>x</i> coordinate of the curve&#x2019;s control
     * point.
     *
     * @param cy the <i>y</i> coordinate of the curve&#x2019;s control
     * point.
     *
     * @param x2 the <i>x</i> coordinate of the curve&#x2019;s end
     * point.
     *
     * @param y2 the <i>y</i> coordinate of the curve&#x2019;s end
     * point.
     */
    public Double(double x1, double y1, double cx, double cy, double x2,
                  double y2)
    {
      this.x1 = x1;
      this.y1 = y1;
      ctrlx = cx;
      ctrly = cy;
      this.x2 = x2;
      this.y2 = y2;
    }

    /**
     * Returns the <i>x</i> coordinate of the curve&#x2019;s start
     * point.
     */
    public double getX1()
    {
      return x1;
    }

    /**
     * Returns the <i>y</i> coordinate of the curve&#x2019;s start
     * point.
     */
    public double getY1()
    {
      return y1;
    }

    /**
     * Returns the curve&#x2019;s start point.
     */
    public Point2D getP1()
    {
      return new Point2D.Double(x1, y1);
    }

    /**
     * Returns the <i>x</i> coordinate of the curve&#x2019;s control
     * point.
     */
    public double getCtrlX()
    {
      return ctrlx;
    }

    /**
     * Returns the <i>y</i> coordinate of the curve&#x2019;s control
     * point.
     */
    public double getCtrlY()
    {
      return ctrly;
    }

    /**
     * Returns the curve&#x2019;s control point.
     */
    public Point2D getCtrlPt()
    {
      return new Point2D.Double(ctrlx, ctrly);
    }

    /**
     * Returns the <i>x</i> coordinate of the curve&#x2019;s end
     * point.
     */
    public double getX2()
    {
      return x2;
    }

    /**
     * Returns the <i>y</i> coordinate of the curve&#x2019;s end
     * point.
     */
    public double getY2()
    {
      return y2;
    }

    /**
     * Returns the curve&#x2019;s end point.
     */
    public Point2D getP2()
    {
      return new Point2D.Double(x2, y2);
    }

    /**
     * Changes the geometry of the curve.
     *
     * @param x1 the <i>x</i> coordinate of the curve&#x2019;s new
     * start point.
     *
     * @param y1 the <i>y</i> coordinate of the curve&#x2019;s new
     * start point.
     *
     * @param cx the <i>x</i> coordinate of the curve&#x2019;s new
     * control point.
     *
     * @param cy the <i>y</i> coordinate of the curve&#x2019;s new
     * control point.
     *
     * @param x2 the <i>x</i> coordinate of the curve&#x2019;s new
     * end point.
     *
     * @param y2 the <i>y</i> coordinate of the curve&#x2019;s new
     * end point.
     */
    public void setCurve(double x1, double y1, double cx, double cy,
                         double x2, double y2)
    {
      this.x1 = x1;
      this.y1 = y1;
      ctrlx = cx;
      ctrly = cy;
      this.x2 = x2;
      this.y2 = y2;
    }

    /**
     * Determines the smallest rectangle that encloses the
     * curve&#x2019;s start, end and control point. As the
     * illustration below shows, the invisible control point may cause
     * the bounds to be much larger than the area that is actually
     * covered by the curve.
     *
     * <p><img src="doc-files/QuadCurve2D-2.png" width="350" height="180"
     * alt="An illustration of the bounds of a QuadCurve2D" />
     */
    public Rectangle2D getBounds2D()
    {
      double nx1 = Math.min(Math.min(x1, ctrlx), x2);
      double ny1 = Math.min(Math.min(y1, ctrly), y2);
      double nx2 = Math.max(Math.max(x1, ctrlx), x2);
      double ny2 = Math.max(Math.max(y1, ctrly), y2);
      return new Rectangle2D.Double(nx1, ny1, nx2 - nx1, ny2 - ny1);
    }
  }

  /**
   * A two-dimensional curve that is parameterized with a quadratic
   * function and stores coordinate values in single-precision
   * floating-point format.
   *
   * @see QuadCurve2D.Double
   *
   * @author Eric Blake ([e-mail])
   * @author Sascha Brawer ([e-mail])
   */
  public static class Float extends QuadCurve2D
  {
    /**
     * The <i>x</i> coordinate of the curve&#x2019;s start point.
     */
    public float x1;

    /**
     * The <i>y</i> coordinate of the curve&#x2019;s start point.
     */
    public float y1;

    /**
     * The <i>x</i> coordinate of the curve&#x2019;s control point.
     */
    public float ctrlx;

    /**
     * The <i>y</i> coordinate of the curve&#x2019;s control point.
     */
    public float ctrly;

    /**
     * The <i>x</i> coordinate of the curve&#x2019;s end point.
     */
    public float x2;

    /**
     * The <i>y</i> coordinate of the curve&#x2019;s end point.
     */
    public float y2;

    /**
     * Constructs a new QuadCurve2D that stores its coordinate values
     * in single-precision floating-point format. All points are
     * initially at position (0, 0).
     */
    public Float()
    {
    }

    /**
     * Constructs a new QuadCurve2D that stores its coordinate values
     * in single-precision floating-point format, specifying the
     * initial position of each point.
     *
     * @param x1 the <i>x</i> coordinate of the curve&#x2019;s start
     * point.
     *
     * @param y1 the <i>y</i> coordinate of the curve&#x2019;s start
     * point.
     *
     * @param cx the <i>x</i> coordinate of the curve&#x2019;s control
     * point.
     *
     * @param cy the <i>y</i> coordinate of the curve&#x2019;s control
     * point.
     *
     * @param x2 the <i>x</i> coordinate of the curve&#x2019;s end
     * point.
     *
     * @param y2 the <i>y</i> coordinate of the curve&#x2019;s end
     * point.
     */
    public Float(float x1, float y1, float cx, float cy, float x2, float y2)
    {
      this.x1 = x1;
      this.y1 = y1;
      ctrlx = cx;
      ctrly = cy;
      this.x2 = x2;
      this.y2 = y2;
    }

    /**
     * Returns the <i>x</i> coordinate of the curve&#x2019;s start
     * point.
     */
    public double getX1()
    {
      return x1;
    }

    /**
     * Returns the <i>y</i> coordinate of the curve&#x2019;s start
     * point.
     */
    public double getY1()
    {
      return y1;
    }

    /**
     * Returns the curve&#x2019;s start point.
     */
    public Point2D getP1()
    {
      return new Point2D.Float(x1, y1);
    }

    /**
     * Returns the <i>x</i> coordinate of the curve&#x2019;s control
     * point.
     */
    public double getCtrlX()
    {
      return ctrlx;
    }

    /**
     * Returns the <i>y</i> coordinate of the curve&#x2019;s control
     * point.
     */
    public double getCtrlY()
    {
      return ctrly;
    }

    /**
     * Returns the curve&#x2019;s control point.
     */
    public Point2D getCtrlPt()
    {
      return new Point2D.Float(ctrlx, ctrly);
    }

    /**
     * Returns the <i>x</i> coordinate of the curve&#x2019;s end
     * point.
     */
    public double getX2()
    {
      return x2;
    }

    /**
     * Returns the <i>y</i> coordinate of the curve&#x2019;s end
     * point.
     */
    public double getY2()
    {
      return y2;
    }

    /**
     * Returns the curve&#x2019;s end point.
     */
    public Point2D getP2()
    {
      return new Point2D.Float(x2, y2);
    }

    /**
     * Changes the geometry of the curve, specifying coordinate values
     * as double-precision floating-point numbers.
     *
     * @param x1 the <i>x</i> coordinate of the curve&#x2019;s new
     * start point.
     *
     * @param y1 the <i>y</i> coordinate of the curve&#x2019;s new
     * start point.
     *
     * @param cx the <i>x</i> coordinate of the curve&#x2019;s new
     * control point.
     *
     * @param cy the <i>y</i> coordinate of the curve&#x2019;s new
     * control point.
     *
     * @param x2 the <i>x</i> coordinate of the curve&#x2019;s new
     * end point.
     *
     * @param y2 the <i>y</i> coordinate of the curve&#x2019;s new
     * end point.
     */
    public void setCurve(double x1, double y1, double cx, double cy,
                         double x2, double y2)
    {
      this.x1 = (float) x1;
      this.y1 = (float) y1;
      ctrlx = (float) cx;
      ctrly = (float) cy;
      this.x2 = (float) x2;
      this.y2 = (float) y2;
    }

    /**
     * Changes the geometry of the curve, specifying coordinate values
     * as single-precision floating-point numbers.
     *
     * @param x1 the <i>x</i> coordinate of the curve&#x2019;s new
     * start point.
     *
     * @param y1 the <i>y</i> coordinate of the curve&#x2019;s new
     * start point.
     *
     * @param cx the <i>x</i> coordinate of the curve&#x2019;s new
     * control point.
     *
     * @param cy the <i>y</i> coordinate of the curve&#x2019;s new
     * control point.
     *
     * @param x2 the <i>x</i> coordinate of the curve&#x2019;s new
     * end point.
     *
     * @param y2 the <i>y</i> coordinate of the curve&#x2019;s new
     * end point.
     */
    public void setCurve(float x1, float y1, float cx, float cy, float x2,
                         float y2)
    {
      this.x1 = x1;
      this.y1 = y1;
      ctrlx = cx;
      ctrly = cy;
      this.x2 = x2;
      this.y2 = y2;
    }

    /**
     * Determines the smallest rectangle that encloses the
     * curve&#x2019;s start, end and control point. As the
     * illustration below shows, the invisible control point may cause
     * the bounds to be much larger than the area that is actually
     * covered by the curve.
     *
     * <p><img src="doc-files/QuadCurve2D-2.png" width="350" height="180"
     * alt="An illustration of the bounds of a QuadCurve2D" />
     */
    public Rectangle2D getBounds2D()
    {
      float nx1 = (float) Math.min(Math.min(x1, ctrlx), x2);
      float ny1 = (float) Math.min(Math.min(y1, ctrly), y2);
      float nx2 = (float) Math.max(Math.max(x1, ctrlx), x2);
      float ny2 = (float) Math.max(Math.max(y1, ctrly), y2);
      return new Rectangle2D.Float(nx1, ny1, nx2 - nx1, ny2 - ny1);
    }
  }
}