http://xmlgraphics.apache.org/batik/batik-awt-util/: Batik AWT utilities (Apache Software Foundation) 
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   The ASF licenses this file to You under the Apache License, Version 2.0
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package org.apache.batik.ext.awt.geom;

import java.awt.Point;
import java.awt.Rectangle;
import java.awt.Shape;
import java.awt.geom.AffineTransform;
import java.awt.geom.GeneralPath;
import java.awt.geom.Line2D;
import java.awt.geom.PathIterator;
import java.awt.geom.Point2D;
import java.awt.geom.Rectangle2D;
import java.io.Serializable;


This class has the same behavior than Polygon2D, except that the figure is not closed. 
Version:$Id: Polyline2D.java 1808001 2017-09-11 09:51:29Z ssteiner $
/**
 * This class has the same behavior than {@link Polygon2D}, except that
 * the figure is not closed.
 *
 * @version $Id: Polyline2D.java 1808001 2017-09-11 09:51:29Z ssteiner $
 */
public class Polyline2D implements Shape, Cloneable, Serializable {

    private static final float ASSUME_ZERO = 0.001f;

    
The total number of points.  The value of npoints
represents the number of points in this Polyline2D.

/**
     * The total number of points.  The value of <code>npoints</code>
     * represents the number of points in this <code>Polyline2D</code>.
     *
     */
    public int npoints;

    
The array of x coordinates. The value of npoints is equal to the number of points in this Polyline2D.

/**
     * The array of <i>x</i> coordinates. The value of {@link #npoints npoints} is equal to the
     * number of points in this <code>Polyline2D</code>.
     *
     */
    public float[] xpoints;

    
The array of x coordinates. The value of npoints is equal to the number of points in this Polyline2D.

/**
     * The array of <i>x</i> coordinates. The value of {@link #npoints npoints} is equal to the
     * number of points in this <code>Polyline2D</code>.
     *
     */
    public float[] ypoints;

    
Bounds of the Polyline2D.

See Also:
  • getBounds()
/**
     * Bounds of the Polyline2D.
     * @see #getBounds()
     */
    protected Rectangle2D bounds;

    private GeneralPath path;
    private GeneralPath closedPath;

    
Creates an empty Polyline2D.

/**
     * Creates an empty Polyline2D.
     */
    public Polyline2D() {
        xpoints = new float[4];
        ypoints = new float[4];
    }

    
Constructs and initializes a Polyline2D from the specified
parameters.

Params:
  • xpoints – an array of x coordinates
  • ypoints – an array of y coordinates
  • npoints – the total number of points in the
                               Polyline2D
Throws:
/**
     * Constructs and initializes a <code>Polyline2D</code> from the specified
     * parameters.
     * @param xpoints an array of <i>x</i> coordinates
     * @param ypoints an array of <i>y</i> coordinates
     * @param npoints the total number of points in the
     *                                <code>Polyline2D</code>
     * @exception  NegativeArraySizeException if the value of
     *                       <code>npoints</code> is negative.
     * @exception  IndexOutOfBoundsException if <code>npoints</code> is
     *             greater than the length of <code>xpoints</code>
     *             or the length of <code>ypoints</code>.
     * @exception  NullPointerException if <code>xpoints</code> or
     *             <code>ypoints</code> is <code>null</code>.
     */
    public Polyline2D(float[] xpoints, float[] ypoints, int npoints) {
        if (npoints > xpoints.length || npoints > ypoints.length) {
            throw new IndexOutOfBoundsException("npoints > xpoints.length || npoints > ypoints.length");
        }
        this.npoints = npoints;
        this.xpoints = new float[npoints+1];   // make space for one more to close the polyline
        this.ypoints = new float[npoints+1];   // make space for one more to close the polyline
        System.arraycopy(xpoints, 0, this.xpoints, 0, npoints);
        System.arraycopy(ypoints, 0, this.ypoints, 0, npoints);
        calculatePath();
    }

    
Constructs and initializes a Polyline2D from the specified
parameters.

Params:
  • xpoints – an array of x coordinates
  • ypoints – an array of y coordinates
  • npoints – the total number of points in the Polyline2D
Throws:
/**
     * Constructs and initializes a <code>Polyline2D</code> from the specified
     * parameters.
     * @param xpoints an array of <i>x</i> coordinates
     * @param ypoints an array of <i>y</i> coordinates
     * @param npoints the total number of points in the <code>Polyline2D</code>
     * @exception  NegativeArraySizeException if the value of
     *                       <code>npoints</code> is negative.
     * @exception  IndexOutOfBoundsException if <code>npoints</code> is
     *             greater than the length of <code>xpoints</code>
     *             or the length of <code>ypoints</code>.
     * @exception  NullPointerException if <code>xpoints</code> or
     *             <code>ypoints</code> is <code>null</code>.
     */
    public Polyline2D(int[] xpoints, int[] ypoints, int npoints) {
        if (npoints > xpoints.length || npoints > ypoints.length) {
            throw new IndexOutOfBoundsException("npoints > xpoints.length || npoints > ypoints.length");
        }
        this.npoints = npoints;
        this.xpoints = new float[npoints];
        this.ypoints = new float[npoints];
        for (int i = 0; i < npoints; i++) {
            this.xpoints[i] = xpoints[i];
            this.ypoints[i] = ypoints[i];
        }
        calculatePath();
    }

    public Polyline2D(Line2D line) {
        npoints = 2;
        xpoints = new float[2];
        ypoints = new float[2];
        xpoints[0] = (float)line.getX1();
        xpoints[1] = (float)line.getX2();
        ypoints[0] = (float)line.getY1();
        ypoints[1] = (float)line.getY2();
        calculatePath();
    }

    
Resets this Polyline2D object to an empty polygon.
The coordinate arrays and the data in them are left untouched
but the number of points is reset to zero to mark the old
vertex data as invalid and to start accumulating new vertex
data at the beginning.
All internally-cached data relating to the old vertices
are discarded.
Note that since the coordinate arrays from before the reset
are reused, creating a new empty Polyline2D might
be more memory efficient than resetting the current one if
the number of vertices in the new polyline data is significantly
smaller than the number of vertices in the data from before the
reset.

/**
     * Resets this <code>Polyline2D</code> object to an empty polygon.
     * The coordinate arrays and the data in them are left untouched
     * but the number of points is reset to zero to mark the old
     * vertex data as invalid and to start accumulating new vertex
     * data at the beginning.
     * All internally-cached data relating to the old vertices
     * are discarded.
     * Note that since the coordinate arrays from before the reset
     * are reused, creating a new empty <code>Polyline2D</code> might
     * be more memory efficient than resetting the current one if
     * the number of vertices in the new polyline data is significantly
     * smaller than the number of vertices in the data from before the
     * reset.
     */
    public void reset() {
        npoints = 0;
        bounds = null;
        path = new GeneralPath();
        closedPath = null;
    }

    public Object clone() {
        Polyline2D pol = new Polyline2D();
        for (int i = 0; i < npoints; i++) {
            pol.addPoint(xpoints[i], ypoints[i]);
        }
        return pol;
    }

    private void calculatePath() {
        path = new GeneralPath();
        path.moveTo(xpoints[0], ypoints[0]);
        for (int i = 1; i < npoints; i++) {
            path.lineTo(xpoints[i], ypoints[i]);
        }
        bounds = path.getBounds2D();
        closedPath = null;
    }

    private void updatePath(float x, float y) {
        closedPath = null;
        if (path == null) {
            path = new GeneralPath(GeneralPath.WIND_EVEN_ODD);
            path.moveTo(x, y);
            bounds = new Rectangle2D.Float(x, y, 0, 0);
        } else {
            path.lineTo(x, y);
            float _xmax = (float)bounds.getMaxX();
            float _ymax = (float)bounds.getMaxY();
            float _xmin = (float)bounds.getMinX();
            float _ymin = (float)bounds.getMinY();
            if (x < _xmin) _xmin = x;
            else if (x > _xmax) _xmax = x;
            if (y < _ymin) _ymin = y;
            else if (y > _ymax) _ymax = y;
            bounds = new Rectangle2D.Float(_xmin, _ymin, _xmax - _xmin, _ymax - _ymin);
        }
    }

    public void addPoint(Point2D p) {
        addPoint((float)p.getX(), (float)p.getY());
    }

    
Appends the specified coordinates to this Polyline2D.


If an operation that calculates the bounding box of this
Polyline2D has already been performed, such as
getBounds or contains, then this
method updates the bounding box.

Params:
  • x – the specified x coordinate
  • y – the specified y coordinate
See Also:
/**
     * Appends the specified coordinates to this <code>Polyline2D</code>.
     * <p>
     * If an operation that calculates the bounding box of this
     * <code>Polyline2D</code> has already been performed, such as
     * <code>getBounds</code> or <code>contains</code>, then this
     * method updates the bounding box.
     * @param       x the specified x coordinate
     * @param       y the specified y coordinate
     * @see         java.awt.Polygon#getBounds
     * @see         java.awt.Polygon#contains(double,double)
     */
    public void addPoint(float x, float y) {
        if (npoints == xpoints.length) {
            float[] tmp;

            tmp = new float[npoints * 2];
            System.arraycopy(xpoints, 0, tmp, 0, npoints);
            xpoints = tmp;

            tmp = new float[npoints * 2];
            System.arraycopy(ypoints, 0, tmp, 0, npoints);
            ypoints = tmp;
        }
        xpoints[npoints] = x;
        ypoints[npoints] = y;
        npoints++;
        updatePath(x, y);
    }

    
Gets the bounding box of this Polyline2D. The bounding box is the smallest Rectangle whose sides are parallel to the x and y axes of the coordinate space, and can completely contain the Polyline2D.

Returns:a Rectangle that defines the bounds of this
Polyline2D.
/**
     * Gets the bounding box of this <code>Polyline2D</code>.
     * The bounding box is the smallest {@link Rectangle} whose
     * sides are parallel to the x and y axes of the
     * coordinate space, and can completely contain the <code>Polyline2D</code>.
     * @return a <code>Rectangle</code> that defines the bounds of this
     * <code>Polyline2D</code>.
     */
    public Rectangle getBounds() {
        if (bounds == null) return null;
        else return bounds.getBounds();
    }

    private void updateComputingPath() {
        if (npoints >= 1) {
            if (closedPath == null) {
                closedPath = (GeneralPath)path.clone();
                closedPath.closePath();
            }
        }
    }

    
Determines whether the specified Point is inside this Polyline2D.
This method is required to implement the Shape interface,
but in the case of Line2D objects it always returns false since a line contains no area.

/**
     * Determines whether the specified {@link Point} is inside this
     * <code>Polyline2D</code>.
     * This method is required to implement the Shape interface,
     * but in the case of Line2D objects it always returns false since a line contains no area.
     */
    public boolean contains(Point p) {
        return false;
    }

    
Determines if the specified coordinates are inside this
Polyline2D.
This method is required to implement the Shape interface,
but in the case of Line2D objects it always returns false since a line contains no area.

/**
     * Determines if the specified coordinates are inside this
     * <code>Polyline2D</code>.
     * This method is required to implement the Shape interface,
     * but in the case of Line2D objects it always returns false since a line contains no area.
     */
    public boolean contains(double x, double y) {
        return false;
    }

    
Determines whether the specified coordinates are inside this
Polyline2D.
This method is required to implement the Shape interface,
but in the case of Line2D objects it always returns false since a line contains no area.

/**
     * Determines whether the specified coordinates are inside this
     * <code>Polyline2D</code>.
     * This method is required to implement the Shape interface,
     * but in the case of Line2D objects it always returns false since a line contains no area.
     */
    public boolean contains(int x, int y) {
        return false;
    }

    
Returns the high precision bounding box of the Shape. 
Returns:a Rectangle2D that precisely bounds the Shape.
/**
     * Returns the high precision bounding box of the {@link Shape}.
     * @return a {@link Rectangle2D} that precisely
     *                bounds the <code>Shape</code>.
     */
    public Rectangle2D getBounds2D() {
        return bounds;
    }

    
Tests if a specified Point2D is inside the boundary of this Polyline2D.
This method is required to implement the Shape interface,
but in the case of Line2D objects it always returns false since a line contains no area.

/**
     * Tests if a specified {@link Point2D} is inside the boundary of this
     * <code>Polyline2D</code>.
     * This method is required to implement the Shape interface,
     * but in the case of Line2D objects it always returns false since a line contains no area.
     */
    public boolean contains(Point2D p) {
        return false;
    }

    
Tests if the interior of this Polygon intersects the
interior of a specified set of rectangular coordinates.

Params:
  • x – the x coordinate of the specified rectangular
                       shape's top-left corner
  • y – the y coordinate of the specified rectangular
                       shape's top-left corner
  • w – the width of the specified rectangular shape
  • h – the height of the specified rectangular shape
Returns:true if the interior of this
                       Polygon and the interior of the
                       specified set of rectangular
                        coordinates intersect each other;
                       false otherwise.
/**
     * Tests if the interior of this <code>Polygon</code> intersects the
     * interior of a specified set of rectangular coordinates.
     * @param x the x coordinate of the specified rectangular
     *                        shape's top-left corner
     * @param y the y coordinate of the specified rectangular
     *                        shape's top-left corner
     * @param w the width of the specified rectangular shape
     * @param h the height of the specified rectangular shape
     * @return <code>true</code> if the interior of this
     *                        <code>Polygon</code> and the interior of the
     *                        specified set of rectangular
     *                         coordinates intersect each other;
     *                        <code>false</code> otherwise.
     */
    public boolean intersects(double x, double y, double w, double h) {
        if (npoints <= 0 || !bounds.intersects(x, y, w, h)) {
            return false;
        }
        updateComputingPath();
        return closedPath.intersects(x, y, w, h);
    }

    
Tests if the interior of this Polygon intersects the
interior of a specified Rectangle2D.

Params:
  • r – a specified Rectangle2D
Returns:true if this Polygon and the
                        interior of the specified Rectangle2D
                        intersect each other; false
                        otherwise.
/**
     * Tests if the interior of this <code>Polygon</code> intersects the
     * interior of a specified <code>Rectangle2D</code>.
     * @param r a specified <code>Rectangle2D</code>
     * @return <code>true</code> if this <code>Polygon</code> and the
     *                         interior of the specified <code>Rectangle2D</code>
     *                         intersect each other; <code>false</code>
     *                         otherwise.
     */
    public boolean intersects(Rectangle2D r) {
        return intersects(r.getX(), r.getY(), r.getWidth(), r.getHeight());
    }

    
Tests if the interior of this Polyline2D entirely
contains the specified set of rectangular coordinates.
This method is required to implement the Shape interface,
but in the case of Line2D objects it always returns false since a line contains no area.

/**
     * Tests if the interior of this <code>Polyline2D</code> entirely
     * contains the specified set of rectangular coordinates.
     * This method is required to implement the Shape interface,
     * but in the case of Line2D objects it always returns false since a line contains no area.
     */
    public boolean contains(double x, double y, double w, double h) {
        return false;
    }

    
Tests if the interior of this Polyline2D entirely
contains the specified Rectangle2D.
This method is required to implement the Shape interface,
but in the case of Line2D objects it always returns false since a line contains no area.

/**
     * Tests if the interior of this <code>Polyline2D</code> entirely
     * contains the specified <code>Rectangle2D</code>.
     * This method is required to implement the Shape interface,
     * but in the case of Line2D objects it always returns false since a line contains no area.
     */
    public boolean contains(Rectangle2D r) {
        return false;
    }

    
Returns an iterator object that iterates along the boundary of this
Polygon and provides access to the geometry
of the outline of this Polygon. An optional AffineTransform can be specified so that the coordinates returned in the iteration are transformed accordingly. 
Params:
  • at – an optional AffineTransform to be applied to the
                coordinates as they are returned in the iteration, or
               null if untransformed coordinates are desired
Returns:a PathIterator object that provides access to the geometry of this Polygon.
/**
     * Returns an iterator object that iterates along the boundary of this
     * <code>Polygon</code> and provides access to the geometry
     * of the outline of this <code>Polygon</code>.  An optional
     * {@link AffineTransform} can be specified so that the coordinates
     * returned in the iteration are transformed accordingly.
     * @param at an optional <code>AffineTransform</code> to be applied to the
     *                 coordinates as they are returned in the iteration, or
     *                <code>null</code> if untransformed coordinates are desired
     * @return a {@link PathIterator} object that provides access to the
     *                geometry of this <code>Polygon</code>.
     */
    public PathIterator getPathIterator(AffineTransform at) {
        if (path == null) return null;
        else return path.getPathIterator(at);
    }

    /* get the associated {@link Polygon2D}.
     * This method take care that may be the last point can
     * be equal to the first. In that case it must not be included in the Polygon,
     * as polygons declare their first point only once.
     */
    public Polygon2D getPolygon2D() {
        Polygon2D pol = new Polygon2D();
        for (int i = 0; i < npoints - 1; i++) {
           pol.addPoint(xpoints[i], ypoints[i]);
        }
        Point2D.Double p0 =
            new Point2D.Double(xpoints[0], ypoints[0]);
        Point2D.Double p1 =
            new Point2D.Double(xpoints[npoints-1], ypoints[npoints-1]);

        if (p0.distance(p1) > ASSUME_ZERO)
            pol.addPoint(xpoints[npoints-1], ypoints[npoints-1]);

        return pol;
    }

    
Returns an iterator object that iterates along the boundary of
the Shape and provides access to the geometry of the
outline of the Shape.  Only SEG_MOVETO and SEG_LINETO, point types
are returned by the iterator.
Since polylines are already flat, the flatness parameter
is ignored.

Params:
  • at – an optional AffineTransform to be applied to the
                coordinates as they are returned in the iteration, or
               null if untransformed coordinates are desired
  • flatness – the maximum amount that the control points
                for a given curve can vary from colinear before a subdivided
               curve is replaced by a straight line connecting the
                endpoints.  Since polygons are already flat the
                flatness parameter is ignored.
Returns:a PathIterator object that provides access to the
                Shape object's geometry.
/**
     * Returns an iterator object that iterates along the boundary of
     * the <code>Shape</code> and provides access to the geometry of the
     * outline of the <code>Shape</code>.  Only SEG_MOVETO and SEG_LINETO, point types
     * are returned by the iterator.
     * Since polylines are already flat, the <code>flatness</code> parameter
     * is ignored.
     * @param at an optional <code>AffineTransform</code> to be applied to the
     *                 coordinates as they are returned in the iteration, or
     *                <code>null</code> if untransformed coordinates are desired
     * @param flatness the maximum amount that the control points
     *                 for a given curve can vary from colinear before a subdivided
     *                curve is replaced by a straight line connecting the
     *                 endpoints.  Since polygons are already flat the
     *                 <code>flatness</code> parameter is ignored.
     * @return a <code>PathIterator</code> object that provides access to the
     *                 <code>Shape</code> object's geometry.
     */
    public PathIterator getPathIterator(AffineTransform at, double flatness) {
        return path.getPathIterator(at);
    }
}