sources/org/apache/batik/ext/awt/geom/Polyline2D.java

/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

*/

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 {@link Polygon2D}, except that
 * the figure is not closed.
 *
 * @version $Id$
 */
public class Polyline2D implements Shape, Cloneable, Serializable {

    private static final float ASSUME_ZERO = 0.001f;

    /**
     * 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 <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 <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 #getBounds()
     */
    protected Rectangle2D bounds;

    private GeneralPath path;
    private GeneralPath closedPath;

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

    /**
     * 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 <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 <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 <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 <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 {@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
     * <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
     * <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 {@link Shape}.
     * @return a {@link Rectangle2D} that precisely
     *                bounds the <code>Shape</code>.
     */
    public Rectangle2D getBounds2D() {
        return bounds;
    }

    /**
     * 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 <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 <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 <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 <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
     * <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 <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);
    }
}