RoundRectangle2D.java

/* RoundRectangle2D.java -- represents a rectangle with rounded corners
   Copyright (C) 2000, 2002, 2003, 2004, 2006, Free Software Foundation

This file is part of GNU Classpath.

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it under the terms of the GNU General Public License as published by
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02110-1301 USA.

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permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
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this exception to your version of the library, but you are not
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package java.awt.geom;



/** This class implements a rectangle with rounded corners.
 * @author Tom Tromey (tromey@cygnus.com)
 * @date December 3, 2000
 */
public abstract class RoundRectangle2D extends RectangularShape
{
  /** 
   * Return the arc height of this round rectangle.  The arc height and width
   * control the roundness of the corners of the rectangle.
   * 
   * @return The arc height.
   * 
   * @see #getArcWidth()
   */
  public abstract double getArcHeight();

  /** 
   * Return the arc width of this round rectangle.  The arc width and height
   * control the roundness of the corners of the rectangle.
   * 
   * @return The arc width.
   * 
   * @see #getArcHeight()
   */
  public abstract double getArcWidth();

  /** 
   * Set the values of this round rectangle.
   * 
   * @param x The x coordinate
   * @param y The y coordinate
   * @param w The width
   * @param h The height
   * @param arcWidth The arc width
   * @param arcHeight The arc height
   */
  public abstract void setRoundRect(double x, double y, double w, double h,
                                    double arcWidth, double arcHeight);

  /** 
   * Create a RoundRectangle2D.  This is protected because this class
   * is abstract and cannot be instantiated.
   */
  protected RoundRectangle2D()
  {
  }

  /** 
   * Return true if this object contains the specified point.
   * @param x The x coordinate
   * @param y The y coordinate
   */
  public boolean contains(double x, double y)
  {
    double mx = getX();
    double mw = getWidth();
    if (x < mx || x >= mx + mw)
      return false;
    double my = getY();
    double mh = getHeight();
    if (y < my || y >= my + mh)
      return false;

    // Now check to see if the point is in range of an arc.
    double dy = Math.min(Math.abs(my - y), Math.abs(my + mh - y));
    double dx = Math.min(Math.abs(mx - x), Math.abs(mx + mw - x));

    // The arc dimensions are that of the corresponding ellipse
    // thus a 90 degree segment is half of that.
    double aw = getArcWidth() / 2.0;
    double ah = getArcHeight() / 2.0;
    if (dx > aw || dy > ah)
      return true;

    // At this point DX represents the distance from the nearest edge
    // of the rectangle.  But we want to transform it to represent the
    // scaled distance from the center of the ellipse that forms the
    // arc.  Hence this code:
    dy = (ah - dy) / ah;
    dx = (aw - dx) / aw;

    return dx * dx + dy * dy <= 1.0;
  }

  /** 
   * Return true if this object contains the specified rectangle
   * @param x The x coordinate
   * @param y The y coordinate
   * @param w The width
   * @param h The height
   */
  public boolean contains(double x, double y, double w, double h)
  {
    // We have to check all four points here (for ordinary rectangles
    // we can just check opposing corners).
    return (contains(x, y) && contains(x, y + h) && contains(x + w, y + h)
           && contains(x + w, y));
  }

  /** 
   * Return a new path iterator which iterates over this rectangle.
   * 
   * @param at An affine transform to apply to the object
   */
  public PathIterator getPathIterator(final AffineTransform at) 
  {
    double arcW = Math.min(getArcWidth(), getWidth());
    double arcH = Math.min(getArcHeight(), getHeight());
    
    // check for special cases...
    if (arcW <= 0 || arcH <= 0)
      {
        Rectangle2D r = new Rectangle2D.Double(getX(), getY(), getWidth(), 
                getHeight());
        return r.getPathIterator(at);
      }
    else if (arcW >= getWidth() && arcH >= getHeight()) 
      {
        Ellipse2D e = new Ellipse2D.Double(getX(), getY(), getWidth(), 
                getHeight());
        return e.getPathIterator(at);
      }
    
    // otherwise return the standard case...
    return new PathIterator() 
      {
        double x = getX();
        double y = getY();
        double w = getWidth();
        double h = getHeight();
        double arcW = Math.min(getArcWidth(), w);
        double arcH = Math.min(getArcHeight(), h);
        Arc2D.Double arc = new Arc2D.Double();
        PathIterator corner;
        int step = -1;

        public int currentSegment(double[] coords) 
        {
          if (corner != null) // steps 1, 3, 5 and 7
          {
            int r = corner.currentSegment(coords);
            if (r == SEG_MOVETO)
              r = SEG_LINETO;
            return r;
          }
          if (step == -1) 
          {
            // move to the start position
            coords[0] = x + w - arcW / 2;
            coords[1] = y;
          }
          else if (step == 0)
          {
            // top line
            coords[0] = x + arcW / 2;
            coords[1] = y;
          }
          else if (step == 2) 
          {
            // left line
            coords[0] = x;
            coords[1] = y + h - arcH / 2;
          }
          else if (step == 4)
          {
            // bottom line
            coords[0] = x + w - arcW / 2;
            coords[1] = y + h;
          }
          else if (step == 6)
          {
            // right line
              coords[0] = x + w;
              coords[1] = y + arcH / 2;
          }
          if (at != null)
            at.transform(coords, 0, coords, 0, 1);
          return step == -1 ? SEG_MOVETO : SEG_LINETO;
        }

        public int currentSegment(float[] coords) {
          if (corner != null) // steps 1, 3, 5 and 7
          {
            int r = corner.currentSegment(coords);
            if (r == SEG_MOVETO)
              r = SEG_LINETO;
            return r;
          }
          if (step == -1) 
          {
            // move to the start position
            coords[0] = (float) (x + w - arcW / 2);
            coords[1] = (float) y;
          }
          else if (step == 0)
          {
            // top line
            coords[0] = (float) (x + arcW / 2);
            coords[1] = (float) y;
          }
          else if (step == 2) 
          {
            // left line
            coords[0] = (float) x;
            coords[1] = (float) (y + h - arcH / 2);
          }
          else if (step == 4)
          {
            // bottom line
            coords[0] = (float) (x + w - arcW / 2);
            coords[1] = (float) (y + h);
          }
          else if (step == 6)
          {
            // right line
            coords[0] = (float) (x + w);
            coords[1] = (float) (y + arcH / 2);
          }
        if (at != null)
          at.transform(coords, 0, coords, 0, 1);
        return step == -1 ? SEG_MOVETO : SEG_LINETO;
      }

      public int getWindingRule() {
        return WIND_NON_ZERO;
      }

      public boolean isDone() {
        return step >= 8;
      }

      public void next() 
      {
        if (corner != null)
          {
            corner.next();
            if (corner.isDone())
              {
                corner = null;
                step++;
              }
          }
        else
          {
            step++;
            if (step == 1) 
              {
                // create top left corner
                arc.setArc(x, y, arcW, arcH, 90, 90, Arc2D.OPEN);
                corner = arc.getPathIterator(at);
              }
            else if (step == 3)
              {
                // create bottom left corner  
                arc.setArc(x, y + h - arcH, arcW, arcH, 180, 90, 
                        Arc2D.OPEN);
                corner = arc.getPathIterator(at);
              }
            else if (step == 5)
              {
                // create bottom right corner  
                arc.setArc(x + w - arcW, y + h - arcH, arcW, arcH, 270, 90,
                        Arc2D.OPEN);
                corner = arc.getPathIterator(at);
              }
            else if (step == 7)
              {
                // create top right corner  
                arc.setArc(x + w - arcW, y, arcW, arcH, 0, 90, Arc2D.OPEN);
                corner = arc.getPathIterator(at);
              }
          }
      }
    };
  }

  /** 
   * Return true if the given rectangle intersects this shape.
   * @param x The x coordinate
   * @param y The y coordinate
   * @param w The width
   * @param h The height
   */
  public boolean intersects(double x, double y, double w, double h)
  {
    // Check if any corner is within the rectangle
    return (contains(x, y) || contains(x, y + h) || contains(x + w, y + h)
           || contains(x + w, y));
  }

  /** 
   * Set the boundary of this round rectangle.
   * @param x The x coordinate
   * @param y The y coordinate
   * @param w The width
   * @param h The height
   */
  public void setFrame(double x, double y, double w, double h)
  {
    // This is a bit lame.
    setRoundRect(x, y, w, h, getArcWidth(), getArcHeight());
  }

  /** 
   * Set the values of this round rectangle to be the same as those
   * of the argument.
   * @param rr The round rectangle to copy
   */
  public void setRoundRect(RoundRectangle2D rr)
  {
    setRoundRect(rr.getX(), rr.getY(), rr.getWidth(), rr.getHeight(),
                 rr.getArcWidth(), rr.getArcHeight());
  }

  /** 
   * A subclass of RoundRectangle which keeps its parameters as
   * doubles.  
   */
  public static class Double extends RoundRectangle2D
  {
    /** The height of the corner arc.  */
    public double archeight;

    /** The width of the corner arc.  */
    public double arcwidth;

    /** The x coordinate of this object.  */
    public double x;

    /** The y coordinate of this object.  */
    public double y;

    /** The width of this object.  */
    public double width;

    /** The height of this object.  */
    public double height;

    /** 
     * Construct a new instance, with all parameters set to 0.  
     */
    public Double()
    {
    }

    /** 
     * Construct a new instance with the given arguments.
     * @param x The x coordinate
     * @param y The y coordinate
     * @param w The width
     * @param h The height
     * @param arcWidth The arc width
     * @param arcHeight The arc height
     */
    public Double(double x, double y, double w, double h, double arcWidth,
                  double arcHeight)
    {
      this.x = x;
      this.y = y;
      this.width = w;
      this.height = h;
      this.arcwidth = arcWidth;
      this.archeight = arcHeight;
    }

    public double getArcHeight()
    {
      return archeight;
    }

    public double getArcWidth()
    {
      return arcwidth;
    }

    public Rectangle2D getBounds2D()
    {
      return new Rectangle2D.Double(x, y, width, height);
    }

    public double getX()
    {
      return x;
    }

    public double getY()
    {
      return y;
    }

    public double getWidth()
    {
      return width;
    }

    public double getHeight()
    {
      return height;
    }

    public boolean isEmpty()
    {
      return width <= 0 || height <= 0;
    }

    public void setRoundRect(double x, double y, double w, double h,
                             double arcWidth, double arcHeight)
    {
      this.x = x;
      this.y = y;
      this.width = w;
      this.height = h;
      this.arcwidth = arcWidth;
      this.archeight = arcHeight;
    }
  } // class Double

  /** 
   * A subclass of RoundRectangle which keeps its parameters as
   * floats.  
   */
  public static class Float extends RoundRectangle2D
  {
    /** The height of the corner arc.  */
    public float archeight;

    /** The width of the corner arc.  */
    public float arcwidth;

    /** The x coordinate of this object.  */
    public float x;

    /** The y coordinate of this object.  */
    public float y;

    /** The width of this object.  */
    public float width;

    /** The height of this object.  */
    public float height;

    /** 
     * Construct a new instance, with all parameters set to 0.  
     */
    public Float()
    {
    }

    /** 
     * Construct a new instance with the given arguments.
     * @param x The x coordinate
     * @param y The y coordinate
     * @param w The width
     * @param h The height
     * @param arcWidth The arc width
     * @param arcHeight The arc height
     */
    public Float(float x, float y, float w, float h, float arcWidth,
                 float arcHeight)
    {
      this.x = x;
      this.y = y;
      this.width = w;
      this.height = h;
      this.arcwidth = arcWidth;
      this.archeight = arcHeight;
    }

    public double getArcHeight()
    {
      return archeight;
    }

    public double getArcWidth()
    {
      return arcwidth;
    }

    public Rectangle2D getBounds2D()
    {
      return new Rectangle2D.Float(x, y, width, height);
    }

    public double getX()
    {
      return x;
    }

    public double getY()
    {
      return y;
    }

    public double getWidth()
    {
      return width;
    }

    public double getHeight()
    {
      return height;
    }

    public boolean isEmpty()
    {
      return width <= 0 || height <= 0;
    }

    /**
     * Sets the dimensions for this rounded rectangle.
     * 
     * @param x  the x-coordinate of the top left corner.
     * @param y  the y-coordinate of the top left corner.
     * @param w  the width of the rectangle.
     * @param h  the height of the rectangle.
     * @param arcWidth  the arc width.
     * @param arcHeight  the arc height.
     * 
     * @see #setRoundRect(double, double, double, double, double, double)
     */
    public void setRoundRect(float x, float y, float w, float h,
                             float arcWidth, float arcHeight)
    {
      this.x = x;
      this.y = y;
      this.width = w;
      this.height = h;
      this.arcwidth = arcWidth;
      this.archeight = arcHeight;
    }

    public void setRoundRect(double x, double y, double w, double h,
                             double arcWidth, double arcHeight)
    {
      this.x = (float) x;
      this.y = (float) y;
      this.width = (float) w;
      this.height = (float) h;
      this.arcwidth = (float) arcWidth;
      this.archeight = (float) arcHeight;
    }
  } // class Float
} // class RoundRectangle2D