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/*

    This file is part of the iText (R) project.
    Copyright (c) 1998-2022 iText Group NV
    Authors: Bruno Lowagie, Paulo Soares, et al.

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License version 3
    as published by the Free Software Foundation with the addition of the
    following permission added to Section 15 as permitted in Section 7(a):
    FOR ANY PART OF THE COVERED WORK IN WHICH THE COPYRIGHT IS OWNED BY
    ITEXT GROUP. ITEXT GROUP DISCLAIMS THE WARRANTY OF NON INFRINGEMENT
    OF THIRD PARTY RIGHTS

    This program 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 Affero General Public License for more details.
    You should have received a copy of the GNU Affero General Public License
    along with this program; if not, see http://www.gnu.org/licenses or write to
    the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
    Boston, MA, 02110-1301 USA, or download the license from the following URL:
    http://itextpdf.com/terms-of-use/

    The interactive user interfaces in modified source and object code versions
    of this program must display Appropriate Legal Notices, as required under
    Section 5 of the GNU Affero General Public License.

    In accordance with Section 7(b) of the GNU Affero General Public License,
    a covered work must retain the producer line in every PDF that is created
    or manipulated using iText.

    You can be released from the requirements of the license by purchasing
    a commercial license. Buying such a license is mandatory as soon as you
    develop commercial activities involving the iText software without
    disclosing the source code of your own applications.
    These activities include: offering paid services to customers as an ASP,
    serving PDFs on the fly in a web application, shipping iText with a closed
    source product.

    For more information, please contact iText Software Corp. at this
    address: [email protected]
 */
package com.itextpdf.kernel.geom;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * Paths define shapes, trajectories, and regions of all sorts. They shall be used
 * to draw lines, define the shapes of filled areas, and specify boundaries for clipping
 * other graphics. A path shall be composed of straight and curved line segments, which
 * may connect to one another or may be disconnected.
 */
public class Path {

    private static final String START_PATH_ERR_MSG = "Path shall start with \"re\" or \"m\" operator";

    private List subpaths = new ArrayList<>();
    private Point currentPoint;

    public Path() {
    }

    public Path(List subpaths) {
        addSubpaths(subpaths);
    }

    public Path(Path path) {
        addSubpaths(path.getSubpaths());
    }

    /**
     * @return A {@link java.util.List} of subpaths forming this path.
     */
    public List getSubpaths() {
        return subpaths;
    }

    /**
     * Adds the subpath to this path.
     *
     * @param subpath The subpath to be added to this path.
     */
    public void addSubpath(Subpath subpath) {
        subpaths.add(subpath);
        currentPoint = subpath.getLastPoint();
    }

    /**
     * Adds the subpaths to this path.
     *
     * @param subpaths {@link java.util.List} of subpaths to be added to this path.
     */
    public void addSubpaths(List subpaths) {
        if (subpaths.size() > 0) {
            for (Subpath subpath : subpaths) {
                this.subpaths.add(new Subpath(subpath));
            }
            currentPoint = this.subpaths.get(subpaths.size() - 1).getLastPoint();
        }
    }

    /**
     * The current point is the trailing endpoint of the segment most recently added to the current path.
     *
     * @return The current point.
     */
    public Point getCurrentPoint() {
        return currentPoint;
    }

    /**
     * Begins a new subpath by moving the current point to coordinates (x, y).
     * @param x x-coordinate of the new point
     * @param y y-coordinate of the new point
     */
    public void moveTo(float x, float y) {
        currentPoint = new Point(x, y);
        Subpath lastSubpath = subpaths.size() > 0 ? subpaths.get(subpaths.size() - 1) : null;

        if (lastSubpath != null && lastSubpath.isSinglePointOpen()) {
            lastSubpath.setStartPoint(currentPoint);
        } else {
            subpaths.add(new Subpath(currentPoint));
        }
    }

    /**
     * Appends a straight line segment from the current point to the point (x, y).
     * @param x x-coordinate of the new point
     * @param y y-coordinate of the new point
     */
    public void lineTo(float x, float y) {
        if (currentPoint == null) {
            throw new RuntimeException(START_PATH_ERR_MSG);
        }
        Point targetPoint = new Point(x, y);
        getLastSubpath().addSegment(new Line(currentPoint, targetPoint));
        currentPoint = targetPoint;
    }

    /**
     * Appends a cubic Bezier curve to the current path. The curve shall extend from
     * the current point to the point (x3, y3).
     * @param x1 x-coordinate of the first control point
     * @param y1 y-coordinate of the first control point
     * @param x2 x-coordinate of the second control point
     * @param y2 y-coordinate of the second control point
     * @param x3 x-coordinate of the third control point
     * @param y3 y-coordinate of the third control point
     */
    public void curveTo(float x1, float y1, float x2, float y2, float x3, float y3) {
        if (currentPoint == null) {
            throw new RuntimeException(START_PATH_ERR_MSG);
        }
        // Numbered in natural order
        Point secondPoint = new Point(x1, y1);
        Point thirdPoint = new Point(x2, y2);
        Point fourthPoint = new Point(x3, y3);

        List controlPoints = new ArrayList<>(Arrays.asList(currentPoint, secondPoint, thirdPoint, fourthPoint));
        getLastSubpath().addSegment(new BezierCurve(controlPoints));

        currentPoint = fourthPoint;
    }

    /**
     * Appends a cubic Bezier curve to the current path. The curve shall extend from
     * the current point to the point (x3, y3) using the current point and
     * (x2, y2) as intermediate control points. Note that current point is both
     * used as the starting point and a control point
     * @param x2 x-coordinate of the second intermediate control point
     * @param y2 y-coordinate of the second intermediate control point
     * @param x3 x-coordinate of the ending point
     * @param y3 y-coordinate of the ending point
     */
    public void curveTo(float x2, float y2, float x3, float y3) {
        if (currentPoint == null) {
            throw new RuntimeException(START_PATH_ERR_MSG);
        }
        curveTo((float) currentPoint.getX(), (float) currentPoint.getY(), x2, y2, x3, y3);
    }

    /**
     * Appends a cubic Bezier curve to the current path. The curve shall extend from
     * the current point to the point (x3, y3) using (x1, y1) and
     * (x3, y3) as control points. Note that (x3, y3) is used both
     * as both a control point and an ending point
     * @param x1 x-coordinate of the first intermediate control point
     * @param y1 y-coordinate of the first intermediate control point
     * @param x3 x-coordinate of the second intermediate control point (and ending point)
     * @param y3 y-coordinate of the second intermediate control point (and ending point)
     */
    public void curveFromTo(float x1, float y1, float x3, float y3) {
        if (currentPoint == null) {
            throw new RuntimeException(START_PATH_ERR_MSG);
        }
        curveTo(x1, y1, x3, y3, x3, y3);
    }

    /**
     * Appends a rectangle to the current path as a complete subpath.
     * @param rect the rectangle to append to the current path
     */
    public void rectangle(Rectangle rect) {
        rectangle(rect.getX(), rect.getY(), rect.getWidth(), rect.getHeight());
    }

    /**
     * Appends a rectangle to the current path as a complete subpath.
     * @param x lower left x-coordinate of the rectangle
     * @param y lower left y-coordinate of the rectangle
     * @param w width of the rectangle
     * @param h height of the rectangle
     */
    public void rectangle(float x, float y, float w, float h) {
        moveTo(x, y);
        lineTo(x + w, y);
        lineTo(x + w, y + h);
        lineTo(x, y + h);
        closeSubpath();
    }

    /**
     * Closes the current subpath.
     */
    public void closeSubpath() {
        if (!isEmpty()) {
            Subpath lastSubpath = getLastSubpath();
            lastSubpath.setClosed(true);

            Point startPoint = lastSubpath.getStartPoint();
            moveTo((float) startPoint.getX(), (float) startPoint.getY());
        }
    }

    /**
     * Closes all subpathes contained in this path.
     */
    public void closeAllSubpaths() {
        for (Subpath subpath : subpaths) {
            subpath.setClosed(true);
        }
    }

    /**
     * Adds additional line to each closed subpath and makes the subpath unclosed.
     * The line connects the last and the first points of the subpaths.
     *
     * @return Indices of modified subpaths.
     */
    public List replaceCloseWithLine() {
        List modifiedSubpathsIndices = new ArrayList<>();
        int i = 0;

        /* It could be replaced with "for" cycle, because IList in C# provides effective
         * access by index. In Java List interface has at least one implementation (LinkedList)
         * which is "bad" for access elements by index.
         */
        for (Subpath subpath : subpaths) {
            if (subpath.isClosed()) {
                subpath.setClosed(false);
                subpath.addSegment(new Line(subpath.getLastPoint(), subpath.getStartPoint()));
                modifiedSubpathsIndices.add(i);
            }
            ++i;
        }

        return modifiedSubpathsIndices;
    }

    /**
     * Path is empty if it contains no subpaths.
     * @return true in case the path is empty and false otherwise
     */
    public boolean isEmpty() {
        return subpaths.size() == 0;
    }

    private Subpath getLastSubpath() {
        assert subpaths.size() > 0;
        return subpaths.get(subpaths.size() - 1);
    }
}




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