line2d.java

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/*
 * @(#)Line2D.java	1.27 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.awt.geom;

import java.awt.Shape;
import java.awt.Rectangle;

/**
 * This <code>Line2D</code> represents a line segment in (x,&nbsp;y)
 * coordinate space.  This class, like all of the Java 2D API, uses a
 * default coordinate system called <i>user space</i> in which the y-axis
 * values increase downward and x-axis values increase to the right.  For
 * more information on the user space coordinate system, see the 
 * <a href="http://java.sun.com/j2se/1.3/docs/guide/2d/spec/j2d-intro.fm2.html#61857">
 * Coordinate Systems</a> section of the Java 2D Programmer's Guide.  
 * <p>
 * This class is only the abstract superclass for all objects that
 * store a 2D line segment.
 * The actual storage representation of the coordinates is left to
 * the subclass.
 *
 * @version 	1.27, 01/23/03
 * @author	Jim Graham
 */
public abstract class Line2D implements Shape, Cloneable {
    /**
     * A line segment specified with float coordinates.
     */
    public static class Float extends Line2D {
	/**
	 * The X coordinate of the start point of the line segment.
	 */
	public float x1;

	/**
	 * The Y coordinate of the start point of the line segment.
	 */
	public float y1;

	/**
	 * The X coordinate of the end point of the line segment.
	 */
	public float x2;

	/**
	 * The Y coordinate of the end point of the line segment.
	 */
	public float y2;

	/**
	 * Constructs and initializes a Line with coordinates (0, 0) -> (0, 0).
	 */
	public Float() {
	}

	/**
	 * Constructs and initializes a Line from the specified coordinates.
	 * @param X1,&nbsp;Y1 the first specified coordinates
	 * @param X2,&nbsp;Y2 the second specified coordinates
	 */
	public Float(float X1, float Y1, float X2, float Y2) {
	    setLine(X1, Y1, X2, Y2);
	}

	/**
	 * Constructs and initializes a <code>Line2D</code> from the
	 * specified {@link Point2D} objects.
	 * @param p1 the first specified <code>Point2D</code>
	 * @param p2 the second specified <code>Point2D</code>
	 */
	public Float(Point2D p1, Point2D p2) {
	    setLine(p1, p2);
	}

	/**
	 * Returns the X coordinate of the start point in double precision.
	 * @return the x coordinate of this <code>Line2D</code> object's 
	 * 	starting point in double precision. 
	 */
	public double getX1() {
	    return (double) x1;
	} 

	/**
	 * Returns the Y coordinate of the start point in double precision.
         * @return the x coordinate of this <code>Line2D</code> object's 
	 *	starting point in double precision.
	 */
	public double getY1() {
	    return (double) y1;
	}

	/**
	 * Returns the start point.
	 * @return the starting <code>Point2D</code> object of this
	 * 	<code>Line2D</code>.
	 */
	public Point2D getP1() {
	    return new Point2D.Float(x1, y1);
	}

	/**
	 * Returns the X coordinate of the end point in double precision.
         * @return the x coordinate of this <code>Line2D</code> object's 
	 * 	ending point in double precision.	
	 */
	public double getX2() {
	    return (double) x2;
	}

	/**
	 * Returns the Y coordinate of the end point in double precision.
         * @return the Y coordinate of this <code>Line2D</code> object's 
	 *	ending point in double precision.
	 */

	public double getY2() {
	    return (double) y2;
	}

	/**
	 * Returns the end point.
         * @return the ending <code>Point2D</code> object of this
         *      <code>Line2D</code>.
	 */
	public Point2D getP2() {
	    return new Point2D.Float(x2, y2);
	}

	/**
	 * Sets the location of the endpoints of this <code>Line2D</code> 
	 * to the specified double coordinates.
	 * @param X1,&nbsp;Y1 the first specified coordinate
	 * @param X2,&nbsp;Y2 the second specified coordinate
	 */
	public void setLine(double X1, double Y1, double X2, double Y2) {
	    this.x1 = (float) X1;
	    this.y1 = (float) Y1;
	    this.x2 = (float) X2;
	    this.y2 = (float) Y2;
	}

	/**
	 * Sets the location of the endpoints of this <code>Line2D</code> 
	 * to the specified float coordinates.
	 * @param X1,&nbsp;Y1 the first specified coordinate
	 * @param X2,&nbsp;Y2 the second specified coordinate
	 */
	public void setLine(float X1, float Y1, float X2, float Y2) {
	    this.x1 = X1;
	    this.y1 = Y1;
	    this.x2 = X2;
	    this.y2 = Y2;
	}

	/**
	 * Returns the high-precision bounding box of this
	 * <code>Line2D</code>.
	 * @return a {@link Rectangle2D} that is the high-precision
	 * 	bounding box of this <code>Line2D</code>.
	 */
	public Rectangle2D getBounds2D() {
	    float x, y, w, h;
	    if (x1 < x2) {
		x = x1;
		w = x2 - x1;
	    } else {
		x = x2;
		w = x1 - x2;
	    }
	    if (y1 < y2) {
		y = y1;
		h = y2 - y1;
	    } else {
		y = y2;
		h = y1 - y2;
	    }
	    return new Rectangle2D.Float(x, y, w, h);
	}
    }

    /**
     * A line segment specified with double coordinates.
     */
    public static class Double extends Line2D {
	/**
	 * The X coordinate of the start point of the line segment.
	 */
	public double x1;

	/**
	 * The Y coordinate of the start point of the line segment.
	 */
	public double y1;

	/**
	 * The X coordinate of the end point of the line segment.
	 */
	public double x2;

	/**
	 * The Y coordinate of the end point of the line segment.
	 */
	public double y2;

	/**
	 * Constructs and initializes a Line with coordinates (0, 0) -> (0, 0).
	 */
	public Double() {
	}

	/**
	 * Constructs and initializes a <code>Line2D</code> from the
         * specified coordinates.
	 * @param X1,&nbsp;Y1 the first specified coordinate
	 * @param X2,&nbsp;Y2 the second specified coordinate
	 */
	public Double(double X1, double Y1, double X2, double Y2) {
	    setLine(X1, Y1, X2, Y2);
	}

	/**
	 * Constructs and initializes a <code>Line2D</code> from the
	 * specified <code>Point2D</code> objects.
	 * @param p1,&nbsp;p2 the specified <code>Point2D</code> objects
	 */
	public Double(Point2D p1, Point2D p2) {
	    setLine(p1, p2);
	}

	/**
	 * Returns the X coordinate of the start point in double precision.
         * @return the X coordinate of this <code>Line2D</code> object's 
	 * 	starting point.
	 */
	public double getX1() {
	    return x1;
	}

	/**
	 * Returns the Y coordinate of the start point in double precision.
         * @return the X coordinate of this <code>Line2D</code> object's 
	 *	starting point.	
	 */
	public double getY1() {
	    return y1;
	}

	/**
	 * Returns the starting <code>Point2D</code> of this
	 * <code>Line2D</code>.
	 * @return the starting <code>Point2D</code> of this
	 * 	<code>Line2D</code>
	 */
	public Point2D getP1() {
	    return new Point2D.Double(x1, y1);
	}

	/**
	 * Returns the X coordinate of the end point in double precision.
         * @return the X coordinate of this <code>Line2D</code> object's 
	 * 	ending point.
	 */
	public double getX2() {
	    return x2;
	}

	/**
	 * Returns the Y coordinate of the end point in double precision.
         * @return the Y coordinate of this <code>Line2D</code> object's 
	 * 	starting point.	
	 */
	public double getY2() {
	    return y2;
	}

	/**
	 * Returns the end <code>Point2D</code> of this
	 * <code>Line2D</code>.
	 * @return the ending <code>Point2D</code> of this 
	 * 	<code>Line2D</code>.
	 */
	public Point2D getP2() {
	    return new Point2D.Double(x2, y2);
	}

	/**
	 * Sets the location of the endpoints of this <code>Line2D</code> 
	 * to the specified double coordinates.
	 * @param X1,&nbsp;Y1 the first specified coordinate
	 * @param X2,&nbsp;Y2 the second specified coordinate
	 */
	public void setLine(double X1, double Y1, double X2, double Y2) {
	    this.x1 = X1;
	    this.y1 = Y1;
	    this.x2 = X2;
	    this.y2 = Y2;
	}

	/**
	 * Returns the high-precision bounding box of this
	 * <code>Line2D</code>.
	 * @return a <code>Rectangle2D</code> that is the high-precision
	 * 	bounding box of this <code>Line2D</code>.
	 */
	public Rectangle2D getBounds2D() {
	    double x, y, w, h;
	    if (x1 < x2) {
		x = x1;
		w = x2 - x1;
	    } else {
		x = x2;
		w = x1 - x2;
	    }
	    if (y1 < y2) {
		y = y1;
		h = y2 - y1;
	    } else {
		y = y2;
		h = y1 - y2;
	    }
	    return new Rectangle2D.Double(x, y, w, h);
	}
    }

    /**
     * This is an abstract class that cannot be instantiated directly.
     * Type-specific implementation subclasses are available for
     * instantiation and provide a number of formats for storing
     * the information necessary to satisfy the various accessory