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package java.awt;

import java.awt.geom.AffineTransform;

import java.awt.geom.PathIterator;

import java.awt.geom.Point2D;

import java.awt.geom.Rectangle2D;

/**

 * The <code>Shape</code> interface provides definitions for objects

 * that represent some form of geometric shape.  The <code>Shape</code>

 * is described by a {@link PathIterator} object, which can express the

 * outline of the <code>Shape</code> as well as a rule for determining

 * how the outline divides the 2D plane into interior and exterior

 * points.  Each <code>Shape</code> object provides callbacks to get the

 * bounding box of the geometry, determine whether points or

 * rectangles lie partly or entirely within the interior

 * of the <code>Shape</code>, and retrieve a <code>PathIterator</code>

 * object that describes the trajectory path of the <code>Shape</code>

 * outline.

 * <p>

 * <a name="def_insideness"><b>Definition of insideness:</b></a>

 * A point is considered to lie inside a

 * <code>Shape</code> if and only if:

 * <ul>

 * <li> it lies completely

 * inside the<code>Shape</code> boundary <i>or</i>

 * <li>

 * it lies exactly on the <code>Shape</code> boundary <i>and</i> the

 * space immediately adjacent to the

 * point in the increasing <code>X</code> direction is

 * entirely inside the boundary <i>or</i>

 * <li>

 * it lies exactly on a horizontal boundary segment <b>and</b> the

 * space immediately adjacent to the point in the

 * increasing <code>Y</code> direction is inside the boundary.

 * </ul>

 * <p>The <code>contains</code> and <code>intersects</code> methods

 * consider the interior of a <code>Shape</code> to be the area it

 * encloses as if it were filled.  This means that these methods

 * consider

 * unclosed shapes to be implicitly closed for the purpose of

 * determining if a shape contains or intersects a rectangle or if a

 * shape contains a point.

 *

 * @see java.awt.geom.PathIterator

 * @see java.awt.geom.AffineTransform

 * @see java.awt.geom.FlatteningPathIterator

 * @see java.awt.geom.GeneralPath

 *

 * @author Jim Graham

 * @since 1.2

 */

public interface Shape {

    /**

     * Returns an integer {@link Rectangle} that completely encloses the

     * <code>Shape</code>.  Note that there is no guarantee that the

     * returned <code>Rectangle</code> is the smallest bounding box that

     * encloses the <code>Shape</code>, only that the <code>Shape</code>

     * lies entirely within the indicated  <code>Rectangle</code>.  The

     * returned <code>Rectangle</code> might also fail to completely

     * enclose the <code>Shape</code> if the <code>Shape</code> overflows

     * the limited range of the integer data type.  The

     * <code>getBounds2D</code> method generally returns a

     * tighter bounding box due to its greater flexibility in

     * representation.

     *

     * <p>

     * Note that the <a href="{@docRoot}/java/awt/Shape.html#def_insideness">

     * definition of insideness</a> can lead to situations where points

     * on the defining outline of the {@code shape} may not be considered

     * contained in the returned {@code bounds} object, but only in cases

     * where those points are also not considered contained in the original

     * {@code shape}.

     * </p>

     * <p>

     * If a {@code point} is inside the {@code shape} according to the

     * {@link #contains(double x, double y) contains(point)} method, then

     * it must be inside the returned {@code Rectangle} bounds object

     * according to the {@link #contains(double x, double y) contains(point)}

     * method of the {@code bounds}. Specifically:

     * </p>

     * <p>

     *  {@code shape.contains(x,y)} requires {@code bounds.contains(x,y)}

     * </p>

     * <p>

     * If a {@code point} is not inside the {@code shape}, then it might

     * still be contained in the {@code bounds} object:

     * </p>

     * <p>

     *  {@code bounds.contains(x,y)} does not imply {@code shape.contains(x,y)}

     * </p>

     * @return an integer <code>Rectangle</code> that completely encloses

     *                 the <code>Shape</code>.

     * @see #getBounds2D

     * @since 1.2

     */

    public Rectangle getBounds();

    /**

     * Returns a high precision and more accurate bounding box of

     * the <code>Shape</code> than the <code>getBounds</code> method.

     * Note that there is no guarantee that the returned

     * {@link Rectangle2D} is the smallest bounding box that encloses

     * the <code>Shape</code>, only that the <code>Shape</code> lies

     * entirely within the indicated <code>Rectangle2D</code>.  The

     * bounding box returned by this method is usually tighter than that

     * returned by the <code>getBounds</code> method and never fails due

     * to overflow problems since the return value can be an instance of

     * the <code>Rectangle2D</code> that uses double precision values to

     * store the dimensions.

     *

     * <p>

     * Note that the <a href="{@docRoot}/java/awt/Shape.html#def_insideness">

     * definition of insideness</a> can lead to situations where points

     * on the defining outline of the {@code shape} may not be considered

     * contained in the returned {@code bounds} object, but only in cases

     * where those points are also not considered contained in the original

     * {@code shape}.

     * </p>

     * <p>

     * If a {@code point} is inside the {@code shape} according to the

     * {@link #contains(Point2D p) contains(point)} method, then it must

     * be inside the returned {@code Rectangle2D} bounds object according

     * to the {@link #contains(Point2D p) contains(point)} method of the

     * {@code bounds}. Specifically:

     * </p>

     * <p>

     *  {@code shape.contains(p)} requires {@code bounds.contains(p)}

     * </p>

     * <p>

     * If a {@code point} is not inside the {@code shape}, then it might

     * still be contained in the {@code bounds} object:

     * </p>

     * <p>

     *  {@code bounds.contains(p)} does not imply {@code shape.contains(p)}

     * </p>

     * @return an instance of <code>Rectangle2D</code> that is a

     *                 high-precision bounding box of the <code>Shape</code>.

     * @see #getBounds

     * @since 1.2

     */

    public Rectangle2D getBounds2D();

    /**

     * Tests if the specified coordinates are inside the boundary of the

     * <code>Shape</code>, as described by the

     * <a href="{@docRoot}/java/awt/Shape.html#def_insideness">

     * definition of insideness</a>.

     * @param x the specified X coordinate to be tested

     * @param y the specified Y coordinate to be tested

     * @return <code>true</code> if the specified coordinates are inside

     *         the <code>Shape</code> boundary; <code>false</code>

     *         otherwise.

     * @since 1.2

     */

    public boolean contains(double x, double y);

    /**

     * Tests if a specified {@link Point2D} is inside the boundary

     * of the <code>Shape</code>, as described by the

     * <a href="{@docRoot}/java/awt/Shape.html#def_insideness">

     * definition of insideness</a>.

     * @param p the specified <code>Point2D</code> to be tested

     * @return <code>true</code> if the specified <code>Point2D</code> is

     *          inside the boundary of the <code>Shape</code>;

     *          <code>false</code> otherwise.

     * @since 1.2

     */

    public boolean contains(Point2D p);

    /**

     * Tests if the interior of the <code>Shape</code> intersects the

     * interior of a specified rectangular area.

     * The rectangular area is considered to intersect the <code>Shape</code>

     * if any point is contained in both the interior of the

     * <code>Shape</code> and the specified rectangular area.

     * <p>

     * The {@code Shape.intersects()} method allows a {@code Shape}

     * implementation to conservatively return {@code true} when:

     * <ul>

     * <li>

     * there is a high probability that the rectangular area and the

     * <code>Shape</code> intersect, but

     * <li>

     * the calculations to accurately determine this intersection

     * are prohibitively expensive.

     * </ul>

     * This means that for some {@code Shapes} this method might

     * return {@code true} even though the rectangular area does not

     * intersect the {@code Shape}.

     * The {@link java.awt.geom.Area Area} class performs

     * more accurate computations of geometric intersection than most

     * {@code Shape} objects and therefore can be used if a more precise

     * answer is required.

     *

     * @param x the X coordinate of the upper-left corner

     *          of the specified rectangular area

     * @param y the Y coordinate of the upper-left corner

     *          of the specified rectangular area

     * @param w the width of the specified rectangular area

     * @param h the height of the specified rectangular area

     * @return <code>true</code> if the interior of the <code>Shape</code> and

     *          the interior of the rectangular area intersect, or are

     *          both highly likely to intersect and intersection calculations

     *          would be too expensive to perform; <code>false</code> otherwise.

     * @see java.awt.geom.Area

     * @since 1.2

     */

    public boolean intersects(double x, double y, double w, double h);

    /**

     * Tests if the interior of the <code>Shape</code> intersects the

     * interior of a specified <code>Rectangle2D</code>.

     * The {@code Shape.intersects()} method allows a {@code Shape}

     * implementation to conservatively return {@code true} when:

     * <ul>

     * <li>

     * there is a high probability that the <code>Rectangle2D</code> and the

     * <code>Shape</code> intersect, but

     * <li>

     * the calculations to accurately determine this intersection

     * are prohibitively expensive.

     * </ul>

     * This means that for some {@code Shapes} this method might

     * return {@code true} even though the {@code Rectangle2D} does not

     * intersect the {@code Shape}.

     * The {@link java.awt.geom.Area Area} class performs

     * more accurate computations of geometric intersection than most

     * {@code Shape} objects and therefore can be used if a more precise

     * answer is required.

     *

     * @param r the specified <code>Rectangle2D</code>

     * @return <code>true</code> if the interior of the <code>Shape</code> and

     *          the interior of the specified <code>Rectangle2D</code>

     *          intersect, or are both highly likely to intersect and intersection

     *          calculations would be too expensive to perform; <code>false</code>

     *          otherwise.

     * @see #intersects(double, double, double, double)

     * @since 1.2

     */

    public boolean intersects(Rectangle2D r);

    /**

     * Tests if the interior of the <code>Shape</code> entirely contains

     * the specified rectangular area.  All coordinates that lie inside

     * the rectangular area must lie within the <code>Shape</code> for the

     * entire rectangular area to be considered contained within the

     * <code>Shape</code>.

     * <p>

     * The {@code Shape.contains()} method allows a {@code Shape}

     * implementation to conservatively return {@code false} when:

     * <ul>

     * <li>

     * the <code>intersect</code> method returns <code>true</code> and

     * <li>

     * the calculations to determine whether or not the

     * <code>Shape</code> entirely contains the rectangular area are

     * prohibitively expensive.

     * </ul>

     * This means that for some {@code Shapes} this method might

     * return {@code false} even though the {@code Shape} contains

     * the rectangular area.

     * The {@link java.awt.geom.Area Area} class performs

     * more accurate geometric computations than most

     * {@code Shape} objects and therefore can be used if a more precise

     * answer is required.

     *

     * @param x the X coordinate of the upper-left corner

     *          of the specified rectangular area

     * @param y the Y coordinate of the upper-left corner

     *          of the specified rectangular area

     * @param w the width of the specified rectangular area

     * @param h the height of the specified rectangular area

     * @return <code>true</code> if the interior of the <code>Shape</code>

     *          entirely contains the specified rectangular area;

     *          <code>false</code> otherwise or, if the <code>Shape</code>

     *          contains the rectangular area and the

     *          <code>intersects</code> method returns <code>true</code>

     *          and the containment calculations would be too expensive to

     *          perform.

     * @see java.awt.geom.Area

     * @see #intersects

     * @since 1.2

     */

    public boolean contains(double x, double y, double w, double h);

    /**

     * Tests if the interior of the <code>Shape</code> entirely contains the

     * specified <code>Rectangle2D</code>.

     * The {@code Shape.contains()} method allows a {@code Shape}

     * implementation to conservatively return {@code false} when:

     * <ul>

     * <li>

     * the <code>intersect</code> method returns <code>true</code> and

     * <li>

     * the calculations to determine whether or not the

     * <code>Shape</code> entirely contains the <code>Rectangle2D</code>

     * are prohibitively expensive.

     * </ul>

     * This means that for some {@code Shapes} this method might

     * return {@code false} even though the {@code Shape} contains

     * the {@code Rectangle2D}.

     * The {@link java.awt.geom.Area Area} class performs

     * more accurate geometric computations than most

     * {@code Shape} objects and therefore can be used if a more precise

     * answer is required.

     *

     * @param r The specified <code>Rectangle2D</code>

     * @return <code>true</code> if the interior of the <code>Shape</code>

     *          entirely contains the <code>Rectangle2D</code>;

     *          <code>false</code> otherwise or, if the <code>Shape</code>

     *          contains the <code>Rectangle2D</code> and the

     *          <code>intersects</code> method returns <code>true</code>

     *          and the containment calculations would be too expensive to

     *          perform.

     * @see #contains(double, double, double, double)

     * @since 1.2

     */

    public boolean contains(Rectangle2D r);

    /**

     * Returns an iterator object that iterates along the

     * <code>Shape</code> boundary and provides access to the geometry of the

     * <code>Shape</code> outline.  If an optional {@link AffineTransform}

     * is specified, the coordinates returned in the iteration are

     * transformed accordingly.

     * <p>

     * Each call to this method returns a fresh <code>PathIterator</code>

     * object that traverses the geometry of the <code>Shape</code> object

     * independently from any other <code>PathIterator</code> objects in use

     * at the same time.

     * <p>

     * It is recommended, but not guaranteed, that objects

     * implementing the <code>Shape</code> interface isolate iterations

     * that are in process from any changes that might occur to the original

     * object's geometry during such iterations.

     *

     * @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 new <code>PathIterator</code> object, which independently

     *          traverses the geometry of the <code>Shape</code>.

     * @since 1.2

     */

    public PathIterator getPathIterator(AffineTransform at);

    /**

     * Returns an iterator object that iterates along the <code>Shape</code>

     * boundary and provides access to a flattened view of the

     * <code>Shape</code> outline geometry.

     * <p>

     * Only SEG_MOVETO, SEG_LINETO, and SEG_CLOSE point types are

     * returned by the iterator.

     * <p>

     * If an optional <code>AffineTransform</code> is specified,

     * the coordinates returned in the iteration are transformed

     * accordingly.

     * <p>

     * The amount of subdivision of the curved segments is controlled

     * by the <code>flatness</code> parameter, which specifies the

     * maximum distance that any point on the unflattened transformed

     * curve can deviate from the returned flattened path segments.

     * Note that a limit on the accuracy of the flattened path might be

     * silently imposed, causing very small flattening parameters to be

     * treated as larger values.  This limit, if there is one, is

     * defined by the particular implementation that is used.

     * <p>

     * Each call to this method returns a fresh <code>PathIterator</code>

     * object that traverses the <code>Shape</code> object geometry

     * independently from any other <code>PathIterator</code> objects in use at

     * the same time.

     * <p>

     * It is recommended, but not guaranteed, that objects

     * implementing the <code>Shape</code> interface isolate iterations

     * that are in process from any changes that might occur to the original

     * object's geometry during such iterations.

     *

     * @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 distance that the line segments used to

     *          approximate the curved segments are allowed to deviate

     *          from any point on the original curve

     * @return a new <code>PathIterator</code> that independently traverses

     *         a flattened view of the geometry of the  <code>Shape</code>.

     * @since 1.2

     */

    public PathIterator getPathIterator(AffineTransform at, double flatness);

}