//******************************************************************************
//
// File: DrawingItem.java
// Package: edu.rit.draw.item
// Unit: Class edu.rit.draw.item.DrawingItem
//
// 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.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.io.Externalizable;
import java.io.IOException;
import java.io.ObjectInput;
import java.io.ObjectOutput;
/**
* Class DrawingItem is the abstract base class for each item on a {@linkplain
* edu.rit.draw.Drawing}. Subclasses provide different kinds of drawing items,
* such as text, lines, and shapes.
*
* Each drawing item is contained within a rectangular bounding box.
* Class DrawingItem's methods return the location and dimensions of the
* bounding box.
*
* @author Alan Kaminsky
* @version 23-Jun-2008
*/
public abstract class DrawingItem
implements Externalizable
{
// Hidden data members.
private static final long serialVersionUID = -7001285340255383829L;
// Exported constructors.
/**
* Construct a new drawing item.
*/
public DrawingItem()
{
}
/**
* Construct a new drawing item that is the same as the given drawing item.
*
* @param theItem Drawing item.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theItem is null.
*/
public DrawingItem
(DrawingItem theItem)
{
}
// Exported operations.
/**
* Returns the size of this drawing item's bounding box.
*
* @return Size.
*/
public Size size()
{
return new Size (width(), height());
}
/**
* Returns the width of this drawing item's bounding box.
*
* @return Width.
*/
public abstract double width();
/**
* Returns the height of this drawing item's bounding box.
*
* @return Height.
*/
public abstract double height();
/**
* Returns the northwest corner point of this drawing item's bounding box.
*
* @return Northwest corner point.
*/
public abstract Point nw();
/**
* Returns the north middle point of this drawing item's bounding box.
*
* @return North middle point.
*/
public Point n()
{
return nw().add (0.5 * width(), 0.0);
}
/**
* Returns the northeast corner point of this drawing item's bounding box.
*
* @return Northeast corner point.
*/
public Point ne()
{
return nw().add (width(), 0.0);
}
/**
* Returns the west middle point of this drawing item's bounding box.
*
* @return West middle point.
*/
public Point w()
{
return nw().add (0.0, 0.5 * height());
}
/**
* Returns the center point of this drawing item's bounding box.
*
* @return Center point.
*/
public Point c()
{
return nw().add (0.5 * width(), 0.5 * height());
}
/**
* Returns the east middle point of this drawing item's bounding box.
*
* @return East middle point.
*/
public Point e()
{
return nw().add (width(), 0.5 * height());
}
/**
* Returns the southwest corner point of this drawing item's bounding box.
*
* @return Southwest corner point.
*/
public Point sw()
{
return nw().add (0.0, height());
}
/**
* Returns the south middle point of this drawing item's bounding box.
*
* @return South middle point.
*/
public Point s()
{
return nw().add (0.5 * width(), height());
}
/**
* Returns the southeast corner point of this drawing item's bounding box.
*
* @return Southeast corner point.
*/
public Point se()
{
return nw().add (width(), height());
}
/**
* Add this drawing item to the end of the default drawing's sequence of
* drawing items.
*
* @return This drawing item.
*
* @exception NullPointerException
* (unchecked exception) Thrown if there is no default drawing.
*
* @see Drawing#defaultDrawing()
*/
public DrawingItem add()
{
doAdd (Drawing.defaultDrawing());
return this;
}
/**
* Add this drawing item to the end of the given drawing's sequence of
* drawing items.
*
* @param theDrawing Drawing.
*
* @return This drawing item.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theDrawing is null.
*/
public DrawingItem add
(Drawing theDrawing)
{
doAdd (theDrawing);
return this;
}
/**
* Add this drawing item to the beginning of the default drawing's sequence
* of drawing items.
*
* @return This drawing item.
*
* @exception NullPointerException
* (unchecked exception) Thrown if there is no default drawing.
*
* @see Drawing#defaultDrawing()
*/
public DrawingItem addFirst()
{
doAddFirst (Drawing.defaultDrawing());
return this;
}
/**
* Add this drawing item to the beginning of the given drawing's sequence of
* drawing items.
*
* @param theDrawing Drawing.
*
* @return This drawing item.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theDrawing is null.
*/
public DrawingItem addFirst
(Drawing theDrawing)
{
doAddFirst (theDrawing);
return this;
}
/**
* Write this drawing item 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
{
}
/**
* Read this drawing item 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 drawing item cannot be
* found.
*/
public void readExternal
(ObjectInput in)
throws IOException, ClassNotFoundException
{
}
/**
* Draw this drawing item in the given graphics context. This method is
* allowed to change the graphics context's paint, stroke, and transform,
* and it doesn't have to change them back.
*
* @param g2d 2-D graphics context.
*/
public void draw
(Graphics2D g2d)
{
}
/**
* Returns the rectangular region this drawing item occupies.
*
* @return Bounding box.
*/
public Rectangle2D boundingBox()
{
Point nw = nw();
return new Rectangle2D.Double (nw.x, nw.y, width(), height());
}
// Hidden operations.
/**
* Add this drawing item to the end of the given drawing's sequence of
* drawing items.
*
* @param theDrawing Drawing.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theDrawing is null.
*/
void doAdd
(Drawing theDrawing)
{
theDrawing.add (this);
}
/**
* Add this drawing item to the beginning of the given drawing's sequence of
* drawing items.
*
* @param theDrawing Drawing.
*
* @exception NullPointerException
* (unchecked exception) Thrown if theDrawing is null.
*/
void doAddFirst
(Drawing theDrawing)
{
theDrawing.addFirst (this);
}
}
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