//******************************************************************************
//
// File: Polygon.java
// Package: edu.rit.draw.item
// Unit: Class edu.rit.draw.item.Polygon
//
// This Java source file is copyright (C) 2008 by Alan Kaminsky. All rights
// reserved. For further information, contact the author, Alan Kaminsky, at
// ark@cs.rit.edu.
//
// This Java source file is part of the Parallel Java Library ("PJ"). PJ is free
// software; you can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// PJ is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
// A PARTICULAR PURPOSE. See the GNU General Public License for more details.
//
// A copy of the GNU General Public License is provided in the file gpl.txt. You
// may also obtain a copy of the GNU General Public License on the World Wide
// Web at http://www.gnu.org/licenses/gpl.html.
//
//******************************************************************************
package edu.rit.draw.item;
import edu.rit.draw.Drawing;
import java.awt.Shape;
import java.awt.geom.GeneralPath;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
import java.util.Iterator;
import java.util.LinkedList;
/**
* Class Polygon provides a polygon {@linkplain DrawingItem} whose boundary
* consists of one or more straight line segments. The polygon has an outline
* and a filled interior.
*
* @author Alan Kaminsky
* @version 23-Jun-2008
*/
public class Polygon
extends ShapeItem
{
// Hidden data members.
private static final long serialVersionUID = -8680229678155189048L;
// Line segment endpoints.
LinkedList myPoints = new LinkedList();
// For adding line segments.
Point myLastPoint;
// For computing the bounding box.
Point myNw;
Point mySe;
Size mySize;
// Exported constructors.
/**
* Construct a new polygon. The polygon has no points initially. The default
* outline and fill paint are used.
*/
public Polygon()
{
super();
}
/**
* Construct a new polygon with the same points, outline, and fill paint as
* the given polygon.
*
* @param thePolygon Polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if thePolygon is null.
*/
public Polygon
(Polygon thePolygon)
{
super (thePolygon);
myPoints.clear();
myPoints.addAll (thePolygon.myPoints);
if (! myPoints.isEmpty())
{
myLastPoint = myPoints.get (myPoints.size()-1);
}
}
// Exported operations.
/**
* Returns the size of this polygon's bounding box.
*
* @return Size.
*/
public Size size()
{
computeBoundingBox();
return mySize;
}
/**
* Returns the width of this polygon's bounding box.
*
* @return Width.
*/
public double width()
{
computeBoundingBox();
return mySize.width;
}
/**
* Returns the height of this polygon's bounding box.
*
* @return Height.
*/
public double height()
{
computeBoundingBox();
return mySize.height;
}
/**
* Returns the northwest corner point of this polygon's bounding box.
*
* @return Northwest corner point.
*/
public Point nw()
{
computeBoundingBox();
return myNw;
}
/**
* Set this polygon's outline.
*
* @param theOutline Outline, or Outline.NONE.
*
* @return This polygon.
*/
public Polygon outline
(Outline theOutline)
{
doOutline (theOutline);
return this;
}
/**
* Set this polygon's fill paint.
*
* @param theFill Fill paint, or Fill.NONE.
*
* @return This polygon.
*/
public Polygon fill
(Fill theFill)
{
doFill (theFill);
return this;
}
/**
* Clear this polygon. All of this polygon's line segments are removed.
*
* @return This polygon.
*/
public Polygon clear()
{
myPoints.clear();
myLastPoint = null;
myNw = null;
return this;
}
/**
* Add a line segment to this polygon. The new endpoint is (x,
* y). If this polygon has no line segments, the to()
* method specifies this polygon's starting endpoint.
*
* @param x Endpoint's X coordinate.
* @param y Endpoint's Y coordinate.
*
* @return This polygon.
*/
public Polygon to
(double x,
double y)
{
return addEndpoint (new Point (x, y));
}
/**
* Add a line segment to this polygon. The new endpoint is
* thePoint. If this polygon has no line segments, the
* to() method specifies this polygon's starting endpoint.
*
* @param thePoint Endpoint.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if thePoint is null.
*/
public Polygon to
(Point thePoint)
{
if (thePoint == null) throw new NullPointerException();
return addEndpoint (thePoint);
}
/**
* Add a horizontal line segment to this polygon. The new endpoint is
* (x, previous endpoint's Y coordinate).
*
* @param x Endpoint's X coordinate.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if there is no previous endpoint.
*/
public Polygon hto
(double x)
{
return addEndpoint (new Point (x, myLastPoint.y));
}
/**
* Add a horizontal line segment to this polygon. The new endpoint is
* (thePoint's X coordinate, previous endpoint's Y coordinate).
*
* @param thePoint Endpoint.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if thePoint is null. Thrown if
* there is no previous endpoint.
*/
public Polygon hto
(Point thePoint)
{
return addEndpoint (new Point (thePoint.x, myLastPoint.y));
}
/**
* Add a vertical line segment to this polygon. The new endpoint is
* (previous endpoint's X coordinate, y).
*
* @param y Endpoint's Y coordinate.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if there is no previous endpoint.
*/
public Polygon vto
(double y)
{
return addEndpoint (new Point (myLastPoint.x, y));
}
/**
* Add a vertical line segment to this polygon. The new endpoint is
* (previous endpoint's X coordinate, thePoint's Y coordinate).
*
* @param thePoint Endpoint.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if thePoint is null. Thrown if
* there is no previous endpoint.
*/
public Polygon vto
(Point thePoint)
{
return addEndpoint (new Point (myLastPoint.x, thePoint.y));
}
/**
* Add a line segment to this polygon. The new endpoint is (previous
* endpoint's X coordinate + dx, previous endpoint's Y coordinate +
* dy).
*
* @param dx X distance.
* @param dy Y distance.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if there is no previous endpoint.
*/
public Polygon by
(double dx,
double dy)
{
return addEndpoint (new Point (myLastPoint.x+dx, myLastPoint.y+dy));
}
/**
* Add a line segment to this polygon. The new endpoint is (previous
* endpoint's X coordinate + theSize.width(), previous endpoint's Y
* coordinate + theSize.height()).
*
* @param theSize Distance.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theSize is null. Thrown if
* there is no previous endpoint.
*/
public Polygon by
(Size theSize)
{
return addEndpoint
(new Point
(myLastPoint.x+theSize.width, myLastPoint.y+theSize.height));
}
/**
* Add a horizontal line segment to this polygon. The new endpoint is
* (previous endpoint's X coordinate + dx, previous endpoint's Y
* coordinate).
*
* @param dx X distance.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if there is no previous endpoint.
*/
public Polygon hby
(double dx)
{
return addEndpoint (new Point (myLastPoint.x+dx, myLastPoint.y));
}
/**
* Add a horizontal line segment to this polygon. The new endpoint is
* (previous endpoint's X coordinate + theSize.width(), previous
* endpoint's Y coordinate).
*
* @param theSize Distance.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theSize is null. Thrown if
* there is no previous endpoint.
*/
public Polygon hby
(Size theSize)
{
return addEndpoint
(new Point (myLastPoint.x+theSize.width, myLastPoint.y));
}
/**
* Add a vertical line segment to this polygon. The new endpoint is
* (previous endpoint's X coordinate, previous endpoint's Y coordinate +
* dy).
*
* @param dy Y distance.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if there is no previous endpoint.
*/
public Polygon vby
(double dy)
{
return addEndpoint (new Point (myLastPoint.x, myLastPoint.y+dy));
}
/**
* Add a vertical line segment to this polygon. The new endpoint is
* (previous endpoint's X coordinate, previous endpoint's Y coordinate +
* theSize.height()).
*
* @param theSize Distance.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theSize is null. Thrown if
* there is no previous endpoint.
*/
public Polygon vby
(Size theSize)
{
return addEndpoint
(new Point (myLastPoint.x, myLastPoint.y+theSize.height));
}
/**
* Add this polygon to the end of the default drawing's sequence of drawing
* items.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if there is no default drawing.
*
* @see Drawing#defaultDrawing()
*/
public Polygon add()
{
doAdd (Drawing.defaultDrawing());
return this;
}
/**
* Add this polygon to the end of the given drawing's sequence of drawing
* items.
*
* @param theDrawing Drawing.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theDrawing is null.
*/
public Polygon add
(Drawing theDrawing)
{
doAdd (theDrawing);
return this;
}
/**
* Add this polygon to the beginning of the default drawing's sequence of
* drawing items.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if there is no default drawing.
*
* @see Drawing#defaultDrawing()
*/
public Polygon addFirst()
{
doAddFirst (Drawing.defaultDrawing());
return this;
}
/**
* Add this polygon to the beginning of the given drawing's sequence of
* drawing items.
*
* @param theDrawing Drawing.
*
* @return This polygon.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theDrawing is null.
*/
public Polygon addFirst
(Drawing theDrawing)
{
doAddFirst (theDrawing);
return this;
}
/**
* Write this polygon to the given object output stream.
*
* @param out Object output stream.
*
* @exception IOException
* Thrown if an I/O error occurred.
*/
public void writeExternal
(ObjectOutput out)
throws IOException
{
super.writeExternal (out);
out.writeInt (myPoints.size());
for (Point point : myPoints)
{
out.writeObject (point);
}
}
/**
* Read this polygon from the given object input stream.
*
* @param in Object input stream.
*
* @exception IOException
* Thrown if an I/O error occurred.
* @exception ClassNotFoundException
* Thrown if any class needed to deserialize this polygon cannot be
* found.
*/
public void readExternal
(ObjectInput in)
throws IOException, ClassNotFoundException
{
super.readExternal (in);
int n = in.readInt();
myPoints.clear();
for (int i = 0; i < n; ++ i)
{
myPoints.add ((Point) in.readObject());
}
if (! myPoints.isEmpty())
{
myLastPoint = myPoints.get (myPoints.size()-1);
}
myNw = null;
mySe = null;
mySize = null;
}
// Hidden operations.
/**
* Add the given endpoint to this polygon.
*/
private Polygon addEndpoint
(Point p)
{
myLastPoint = p;
myPoints.add (p);
myNw = null;
return this;
}
/**
* Compute this polygon's bounding box from myPoints. The results are stored
* in myNw, mySe, and mySize.
*/
private void computeBoundingBox()
{
if (myNw == null)
{
myNw = new Point
(Double.POSITIVE_INFINITY, Double.POSITIVE_INFINITY);
mySe = new Point
(Double.NEGATIVE_INFINITY, Double.NEGATIVE_INFINITY);
for (Point p : myPoints)
{
myNw = myNw.min (p);
mySe = mySe.max (p);
}
mySize = mySe.difference (myNw);
}
}
/**
* Determine the 2-D graphics shape that this shape object will draw.
*
* @return Shape.
*/
Shape getShape()
{
GeneralPath path = new GeneralPath();
int n = myPoints.size();
Iterator iter = myPoints.iterator();
Point point = null;
if (n > 0)
{
point = iter.next();
path.moveTo ((float) point.x, (float) point.y);
while (iter.hasNext())
{
point = iter.next();
path.lineTo ((float) point.x, (float) point.y);
}
path.closePath();
}
return path;
}
}
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