jdk/src/share/classes/java/awt/Polygon.java
changeset 2 90ce3da70b43
child 5506 202f599c92aa
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/java/awt/Polygon.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,677 @@
+/*
+ * Copyright 1995-2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code 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
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+package java.awt;
+
+import java.awt.geom.AffineTransform;
+import java.awt.geom.PathIterator;
+import java.awt.geom.Point2D;
+import java.awt.geom.Rectangle2D;
+import sun.awt.geom.Crossings;
+import java.util.Arrays;
+
+/**
+ * The <code>Polygon</code> class encapsulates a description of a
+ * closed, two-dimensional region within a coordinate space. This
+ * region is bounded by an arbitrary number of line segments, each of
+ * which is one side of the polygon. Internally, a polygon
+ * comprises of a list of {@code (x,y)}
+ * coordinate pairs, where each pair defines a <i>vertex</i> of the
+ * polygon, and two successive pairs are the endpoints of a
+ * line that is a side of the polygon. The first and final
+ * pairs of {@code (x,y)} points are joined by a line segment
+ * that closes the polygon.  This <code>Polygon</code> is defined with
+ * an even-odd winding rule.  See
+ * {@link java.awt.geom.PathIterator#WIND_EVEN_ODD WIND_EVEN_ODD}
+ * for a definition of the even-odd winding rule.
+ * This class's hit-testing methods, which include the
+ * <code>contains</code>, <code>intersects</code> and <code>inside</code>
+ * methods, use the <i>insideness</i> definition described in the
+ * {@link Shape} class comments.
+ *
+ * @author      Sami Shaio
+ * @see Shape
+ * @author      Herb Jellinek
+ * @since       1.0
+ */
+public class Polygon implements Shape, java.io.Serializable {
+
+    /**
+     * The total number of points.  The value of <code>npoints</code>
+     * represents the number of valid points in this <code>Polygon</code>
+     * and might be less than the number of elements in
+     * {@link #xpoints xpoints} or {@link #ypoints ypoints}.
+     * This value can be NULL.
+     *
+     * @serial
+     * @see #addPoint(int, int)
+     * @since 1.0
+     */
+    public int npoints;
+
+    /**
+     * The array of X coordinates.  The number of elements in
+     * this array might be more than the number of X coordinates
+     * in this <code>Polygon</code>.  The extra elements allow new points
+     * to be added to this <code>Polygon</code> without re-creating this
+     * array.  The value of {@link #npoints npoints} is equal to the
+     * number of valid points in this <code>Polygon</code>.
+     *
+     * @serial
+     * @see #addPoint(int, int)
+     * @since 1.0
+     */
+    public int xpoints[];
+
+    /**
+     * The array of Y coordinates.  The number of elements in
+     * this array might be more than the number of Y coordinates
+     * in this <code>Polygon</code>.  The extra elements allow new points
+     * to be added to this <code>Polygon</code> without re-creating this
+     * array.  The value of <code>npoints</code> is equal to the
+     * number of valid points in this <code>Polygon</code>.
+     *
+     * @serial
+     * @see #addPoint(int, int)
+     * @since 1.0
+     */
+    public int ypoints[];
+
+    /**
+     * The bounds of this {@code Polygon}.
+     * This value can be null.
+     *
+     * @serial
+     * @see #getBoundingBox()
+     * @see #getBounds()
+     * @since 1.0
+     */
+    protected Rectangle bounds;
+
+    /*
+     * JDK 1.1 serialVersionUID
+     */
+    private static final long serialVersionUID = -6460061437900069969L;
+
+    /*
+     * Default length for xpoints and ypoints.
+     */
+    private static final int MIN_LENGTH = 4;
+
+    /**
+     * Creates an empty polygon.
+     * @since 1.0
+     */
+    public Polygon() {
+        xpoints = new int[MIN_LENGTH];
+        ypoints = new int[MIN_LENGTH];
+    }
+
+    /**
+     * Constructs and initializes a <code>Polygon</code> from the specified
+     * parameters.
+     * @param xpoints an array of X coordinates
+     * @param ypoints an array of Y coordinates
+     * @param npoints the total number of points in the
+     *                          <code>Polygon</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>.
+     * @since 1.0
+     */
+    public Polygon(int xpoints[], int ypoints[], int npoints) {
+        // Fix 4489009: should throw IndexOutofBoundsException instead
+        // of OutofMemoryException if npoints is huge and > {x,y}points.length
+        if (npoints > xpoints.length || npoints > ypoints.length) {
+            throw new IndexOutOfBoundsException("npoints > xpoints.length || "+
+                                                "npoints > ypoints.length");
+        }
+        // Fix 6191114: should throw NegativeArraySizeException with
+        // negative npoints
+        if (npoints < 0) {
+            throw new NegativeArraySizeException("npoints < 0");
+        }
+        // Fix 6343431: Applet compatibility problems if arrays are not
+        // exactly npoints in length
+        this.npoints = npoints;
+        this.xpoints = Arrays.copyOf(xpoints, npoints);
+        this.ypoints = Arrays.copyOf(ypoints, npoints);
+    }
+
+    /**
+     * Resets this <code>Polygon</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>Polygon</code> might
+     * be more memory efficient than resetting the current one if
+     * the number of vertices in the new polygon data is significantly
+     * smaller than the number of vertices in the data from before the
+     * reset.
+     * @see         java.awt.Polygon#invalidate
+     * @since 1.4
+     */
+    public void reset() {
+        npoints = 0;
+        bounds = null;
+    }
+
+    /**
+     * Invalidates or flushes any internally-cached data that depends
+     * on the vertex coordinates of this <code>Polygon</code>.
+     * This method should be called after any direct manipulation
+     * of the coordinates in the <code>xpoints</code> or
+     * <code>ypoints</code> arrays to avoid inconsistent results
+     * from methods such as <code>getBounds</code> or <code>contains</code>
+     * that might cache data from earlier computations relating to
+     * the vertex coordinates.
+     * @see         java.awt.Polygon#getBounds
+     * @since 1.4
+     */
+    public void invalidate() {
+        bounds = null;
+    }
+
+    /**
+     * Translates the vertices of the <code>Polygon</code> by
+     * <code>deltaX</code> along the x axis and by
+     * <code>deltaY</code> along the y axis.
+     * @param deltaX the amount to translate along the X axis
+     * @param deltaY the amount to translate along the Y axis
+     * @since 1.1
+     */
+    public void translate(int deltaX, int deltaY) {
+        for (int i = 0; i < npoints; i++) {
+            xpoints[i] += deltaX;
+            ypoints[i] += deltaY;
+        }
+        if (bounds != null) {
+            bounds.translate(deltaX, deltaY);
+        }
+    }
+
+    /*
+     * Calculates the bounding box of the points passed to the constructor.
+     * Sets <code>bounds</code> to the result.
+     * @param xpoints[] array of <i>x</i> coordinates
+     * @param ypoints[] array of <i>y</i> coordinates
+     * @param npoints the total number of points
+     */
+    void calculateBounds(int xpoints[], int ypoints[], int npoints) {
+        int boundsMinX = Integer.MAX_VALUE;
+        int boundsMinY = Integer.MAX_VALUE;
+        int boundsMaxX = Integer.MIN_VALUE;
+        int boundsMaxY = Integer.MIN_VALUE;
+
+        for (int i = 0; i < npoints; i++) {
+            int x = xpoints[i];
+            boundsMinX = Math.min(boundsMinX, x);
+            boundsMaxX = Math.max(boundsMaxX, x);
+            int y = ypoints[i];
+            boundsMinY = Math.min(boundsMinY, y);
+            boundsMaxY = Math.max(boundsMaxY, y);
+        }
+        bounds = new Rectangle(boundsMinX, boundsMinY,
+                               boundsMaxX - boundsMinX,
+                               boundsMaxY - boundsMinY);
+    }
+
+    /*
+     * Resizes the bounding box to accomodate the specified coordinates.
+     * @param x,&nbsp;y the specified coordinates
+     */
+    void updateBounds(int x, int y) {
+        if (x < bounds.x) {
+            bounds.width = bounds.width + (bounds.x - x);
+            bounds.x = x;
+        }
+        else {
+            bounds.width = Math.max(bounds.width, x - bounds.x);
+            // bounds.x = bounds.x;
+        }
+
+        if (y < bounds.y) {
+            bounds.height = bounds.height + (bounds.y - y);
+            bounds.y = y;
+        }
+        else {
+            bounds.height = Math.max(bounds.height, y - bounds.y);
+            // bounds.y = bounds.y;
+        }
+    }
+
+    /**
+     * Appends the specified coordinates to this <code>Polygon</code>.
+     * <p>
+     * If an operation that calculates the bounding box of this
+     * <code>Polygon</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
+     * @since 1.0
+     */
+    public void addPoint(int x, int y) {
+        if (npoints >= xpoints.length || npoints >= ypoints.length) {
+            int newLength = npoints * 2;
+            // Make sure that newLength will be greater than MIN_LENGTH and
+            // aligned to the power of 2
+            if (newLength < MIN_LENGTH) {
+                newLength = MIN_LENGTH;
+            } else if ((newLength & (newLength - 1)) != 0) {
+                newLength = Integer.highestOneBit(newLength);
+            }
+
+            xpoints = Arrays.copyOf(xpoints, newLength);
+            ypoints = Arrays.copyOf(ypoints, newLength);
+        }
+        xpoints[npoints] = x;
+        ypoints[npoints] = y;
+        npoints++;
+        if (bounds != null) {
+            updateBounds(x, y);
+        }
+    }
+
+    /**
+     * Gets the bounding box of this <code>Polygon</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>Polygon</code>.
+     * @return a <code>Rectangle</code> that defines the bounds of this
+     * <code>Polygon</code>.
+     * @since 1.1
+     */
+    public Rectangle getBounds() {
+        return getBoundingBox();
+    }
+
+    /**
+     * Returns the bounds of this <code>Polygon</code>.
+     * @return the bounds of this <code>Polygon</code>.
+     * @deprecated As of JDK version 1.1,
+     * replaced by <code>getBounds()</code>.
+     * @since 1.0
+     */
+    @Deprecated
+    public Rectangle getBoundingBox() {
+        if (npoints == 0) {
+            return new Rectangle();
+        }
+        if (bounds == null) {
+            calculateBounds(xpoints, ypoints, npoints);
+        }
+        return bounds.getBounds();
+    }
+
+    /**
+     * Determines whether the specified {@link Point} is inside this
+     * <code>Polygon</code>.
+     * @param p the specified <code>Point</code> to be tested
+     * @return <code>true</code> if the <code>Polygon</code> contains the
+     *                  <code>Point</code>; <code>false</code> otherwise.
+     * @see #contains(double, double)
+     * @since 1.0
+     */
+    public boolean contains(Point p) {
+        return contains(p.x, p.y);
+    }
+
+    /**
+     * Determines whether the specified coordinates are inside this
+     * <code>Polygon</code>.
+     * <p>
+     * @param x the specified X coordinate to be tested
+     * @param y the specified Y coordinate to be tested
+     * @return {@code true} if this {@code Polygon} contains
+     *         the specified coordinates {@code (x,y)};
+     *         {@code false} otherwise.
+     * @see #contains(double, double)
+     * @since 1.1
+     */
+    public boolean contains(int x, int y) {
+        return contains((double) x, (double) y);
+    }
+
+    /**
+     * Determines whether the specified coordinates are contained in this
+     * <code>Polygon</code>.
+     * @param x the specified X coordinate to be tested
+     * @param y the specified Y coordinate to be tested
+     * @return {@code true} if this {@code Polygon} contains
+     *         the specified coordinates {@code (x,y)};
+     *         {@code false} otherwise.
+     * @see #contains(double, double)
+     * @deprecated As of JDK version 1.1,
+     * replaced by <code>contains(int, int)</code>.
+     * @since 1.0
+     */
+    @Deprecated
+    public boolean inside(int x, int y) {
+        return contains((double) x, (double) y);
+    }
+
+    /**
+     * {@inheritDoc}
+     * @since 1.2
+     */
+    public Rectangle2D getBounds2D() {
+        return getBounds();
+    }
+
+    /**
+     * {@inheritDoc}
+     * @since 1.2
+     */
+    public boolean contains(double x, double y) {
+        if (npoints <= 2 || !getBoundingBox().contains(x, y)) {
+            return false;
+        }
+        int hits = 0;
+
+        int lastx = xpoints[npoints - 1];
+        int lasty = ypoints[npoints - 1];
+        int curx, cury;
+
+        // Walk the edges of the polygon
+        for (int i = 0; i < npoints; lastx = curx, lasty = cury, i++) {
+            curx = xpoints[i];
+            cury = ypoints[i];
+
+            if (cury == lasty) {
+                continue;
+            }
+
+            int leftx;
+            if (curx < lastx) {
+                if (x >= lastx) {
+                    continue;
+                }
+                leftx = curx;
+            } else {
+                if (x >= curx) {
+                    continue;
+                }
+                leftx = lastx;
+            }
+
+            double test1, test2;
+            if (cury < lasty) {
+                if (y < cury || y >= lasty) {
+                    continue;
+                }
+                if (x < leftx) {
+                    hits++;
+                    continue;
+                }
+                test1 = x - curx;
+                test2 = y - cury;
+            } else {
+                if (y < lasty || y >= cury) {
+                    continue;
+                }
+                if (x < leftx) {
+                    hits++;
+                    continue;
+                }
+                test1 = x - lastx;
+                test2 = y - lasty;
+            }
+
+            if (test1 < (test2 / (lasty - cury) * (lastx - curx))) {
+                hits++;
+            }
+        }
+
+        return ((hits & 1) != 0);
+    }
+
+    private Crossings getCrossings(double xlo, double ylo,
+                                   double xhi, double yhi)
+    {
+        Crossings cross = new Crossings.EvenOdd(xlo, ylo, xhi, yhi);
+        int lastx = xpoints[npoints - 1];
+        int lasty = ypoints[npoints - 1];
+        int curx, cury;
+
+        // Walk the edges of the polygon
+        for (int i = 0; i < npoints; i++) {
+            curx = xpoints[i];
+            cury = ypoints[i];
+            if (cross.accumulateLine(lastx, lasty, curx, cury)) {
+                return null;
+            }
+            lastx = curx;
+            lasty = cury;
+        }
+
+        return cross;
+    }
+
+    /**
+     * {@inheritDoc}
+     * @since 1.2
+     */
+    public boolean contains(Point2D p) {
+        return contains(p.getX(), p.getY());
+    }
+
+    /**
+     * {@inheritDoc}
+     * @since 1.2
+     */
+    public boolean intersects(double x, double y, double w, double h) {
+        if (npoints <= 0 || !getBoundingBox().intersects(x, y, w, h)) {
+            return false;
+        }
+
+        Crossings cross = getCrossings(x, y, x+w, y+h);
+        return (cross == null || !cross.isEmpty());
+    }
+
+    /**
+     * {@inheritDoc}
+     * @since 1.2
+     */
+    public boolean intersects(Rectangle2D r) {
+        return intersects(r.getX(), r.getY(), r.getWidth(), r.getHeight());
+    }
+
+    /**
+     * {@inheritDoc}
+     * @since 1.2
+     */
+    public boolean contains(double x, double y, double w, double h) {
+        if (npoints <= 0 || !getBoundingBox().intersects(x, y, w, h)) {
+            return false;
+        }
+
+        Crossings cross = getCrossings(x, y, x+w, y+h);
+        return (cross != null && cross.covers(y, y+h));
+    }
+
+    /**
+     * {@inheritDoc}
+     * @since 1.2
+     */
+    public boolean contains(Rectangle2D r) {
+        return contains(r.getX(), r.getY(), r.getWidth(), r.getHeight());
+    }
+
+    /**
+     * 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>.
+     * @since 1.2
+     */
+    public PathIterator getPathIterator(AffineTransform at) {
+        return new PolygonPathIterator(this, at);
+    }
+
+    /**
+     * 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, SEG_LINETO, and
+     * SEG_CLOSE point types are returned by the iterator.
+     * Since polygons are already flat, the <code>flatness</code> parameter
+     * is ignored.  An optional <code>AffineTransform</code> can be specified
+     * in which case 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
+     * @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.
+     * @since 1.2
+     */
+    public PathIterator getPathIterator(AffineTransform at, double flatness) {
+        return getPathIterator(at);
+    }
+
+    class PolygonPathIterator implements PathIterator {
+        Polygon poly;
+        AffineTransform transform;
+        int index;
+
+        public PolygonPathIterator(Polygon pg, AffineTransform at) {
+            poly = pg;
+            transform = at;
+            if (pg.npoints == 0) {
+                // Prevent a spurious SEG_CLOSE segment
+                index = 1;
+            }
+        }
+
+        /**
+         * Returns the winding rule for determining the interior of the
+         * path.
+         * @return an integer representing the current winding rule.
+         * @see PathIterator#WIND_NON_ZERO
+         */
+        public int getWindingRule() {
+            return WIND_EVEN_ODD;
+        }
+
+        /**
+         * Tests if there are more points to read.
+         * @return <code>true</code> if there are more points to read;
+         *          <code>false</code> otherwise.
+         */
+        public boolean isDone() {
+            return index > poly.npoints;
+        }
+
+        /**
+         * Moves the iterator forwards, along the primary direction of
+         * traversal, to the next segment of the path when there are
+         * more points in that direction.
+         */
+        public void next() {
+            index++;
+        }
+
+        /**
+         * Returns the coordinates and type of the current path segment in
+         * the iteration.
+         * The return value is the path segment type:
+         * SEG_MOVETO, SEG_LINETO, or SEG_CLOSE.
+         * A <code>float</code> array of length 2 must be passed in and
+         * can be used to store the coordinates of the point(s).
+         * Each point is stored as a pair of <code>float</code> x,&nbsp;y
+         * coordinates.  SEG_MOVETO and SEG_LINETO types return one
+         * point, and SEG_CLOSE does not return any points.
+         * @param coords a <code>float</code> array that specifies the
+         * coordinates of the point(s)
+         * @return an integer representing the type and coordinates of the
+         *              current path segment.
+         * @see PathIterator#SEG_MOVETO
+         * @see PathIterator#SEG_LINETO
+         * @see PathIterator#SEG_CLOSE
+         */
+        public int currentSegment(float[] coords) {
+            if (index >= poly.npoints) {
+                return SEG_CLOSE;
+            }
+            coords[0] = poly.xpoints[index];
+            coords[1] = poly.ypoints[index];
+            if (transform != null) {
+                transform.transform(coords, 0, coords, 0, 1);
+            }
+            return (index == 0 ? SEG_MOVETO : SEG_LINETO);
+        }
+
+        /**
+         * Returns the coordinates and type of the current path segment in
+         * the iteration.
+         * The return value is the path segment type:
+         * SEG_MOVETO, SEG_LINETO, or SEG_CLOSE.
+         * A <code>double</code> array of length 2 must be passed in and
+         * can be used to store the coordinates of the point(s).
+         * Each point is stored as a pair of <code>double</code> x,&nbsp;y
+         * coordinates.
+         * SEG_MOVETO and SEG_LINETO types return one point,
+         * and SEG_CLOSE does not return any points.
+         * @param coords a <code>double</code> array that specifies the
+         * coordinates of the point(s)
+         * @return an integer representing the type and coordinates of the
+         *              current path segment.
+         * @see PathIterator#SEG_MOVETO
+         * @see PathIterator#SEG_LINETO
+         * @see PathIterator#SEG_CLOSE
+         */
+        public int currentSegment(double[] coords) {
+            if (index >= poly.npoints) {
+                return SEG_CLOSE;
+            }
+            coords[0] = poly.xpoints[index];
+            coords[1] = poly.ypoints[index];
+            if (transform != null) {
+                transform.transform(coords, 0, coords, 0, 1);
+            }
+            return (index == 0 ? SEG_MOVETO : SEG_LINETO);
+        }
+    }
+}