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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);
}