Shape
interface provides definitions for objects
that represent some form of geometric shape. The Shape
is described by a PathIterator object, which can express the
outline of the Shape
as well as a rule for determining
how the outline divides the 2D plane into interior and exterior
points. Each Shape
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 Shape
, and retrieve a PathIterator
object that describes the trajectory path of the Shape
outline.
Definition of insideness:
A point is considered to lie inside a
Shape
if and only if:
Shape
boundary or
Shape
boundary and the
space immediately adjacent to the
point in the increasing X
direction is
entirely inside the boundary or
Y
direction is inside the boundary.
The contains
and intersects
methods
consider the interior of a Shape
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.
Jim
 Graham1.2
 Method from java.awt.Shape Summary: 

contains, contains, contains, contains, getBounds, getBounds2D, getPathIterator, getPathIterator, intersects, intersects 
Method from java.awt.Shape Detail: 

public boolean contains(Point2D p)
Shape , as described by the
definition of insideness. 
public boolean contains(Rectangle2D r)
Shape entirely contains the
specified Rectangle2D .
The {@code Shape.contains()} method allows a {@code Shape}
implementation to conservatively return {@code false} when:

public boolean contains(double x, double y)
Shape , as described by the
definition of insideness. 
public boolean contains(double x, double y, double w, double h)
Shape entirely contains
the specified rectangular area. All coordinates that lie inside
the rectangular area must lie within the Shape for the
entire rectanglar area to be considered contained within the
Shape .
The {@code Shape.contains()} method allows a {@code Shape} implementation to conservatively return {@code false} when: 
public Rectangle getBounds()
Shape . Note that there is no guarantee that the
returned Rectangle is the smallest bounding box that
encloses the Shape , only that the Shape
lies entirely within the indicated Rectangle . The
returned Rectangle might also fail to completely
enclose the Shape if the Shape overflows
the limited range of the integer data type. The
getBounds2D method generally returns a
tighter bounding box due to its greater flexibility in
representation.
Note that the definition of insideness 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}. If a {@code point} is inside the {@code shape} according to the contains(point) method, then it must be inside the returned {@code Rectangle} bounds object according to the contains(point) method of the {@code bounds}. Specifically: {@code shape.contains(x,y)} requires {@code bounds.contains(x,y)} If a {@code point} is not inside the {@code shape}, then it might still be contained in the {@code bounds} object: {@code bounds.contains(x,y)} does not imply {@code shape.contains(x,y)} 
public Rectangle2D getBounds2D()
Shape than the getBounds method.
Note that there is no guarantee that the returned
Rectangle2D is the smallest bounding box that encloses
the Shape , only that the Shape lies
entirely within the indicated Rectangle2D . The
bounding box returned by this method is usually tighter than that
returned by the getBounds method and never fails due
to overflow problems since the return value can be an instance of
the Rectangle2D that uses double precision values to
store the dimensions.
Note that the definition of insideness 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}. If a {@code point} is inside the {@code shape} according to the contains(point) method, then it must be inside the returned {@code Rectangle2D} bounds object according to the contains(point) method of the {@code bounds}. Specifically: {@code shape.contains(p)} requires {@code bounds.contains(p)} If a {@code point} is not inside the {@code shape}, then it might still be contained in the {@code bounds} object: {@code bounds.contains(p)} does not imply {@code shape.contains(p)} 
public PathIterator getPathIterator(AffineTransform at)
Shape boundary and provides access to the geometry of the
Shape outline. If an optional AffineTransform
is specified, the coordinates returned in the iteration are
transformed accordingly.
Each call to this method returns a fresh
It is recommended, but not guaranteed, that objects
implementing the 
public PathIterator getPathIterator(AffineTransform at, double flatness)
Shape
boundary and provides access to a flattened view of the
Shape outline geometry.
Only SEG_MOVETO, SEG_LINETO, and SEG_CLOSE point types are returned by the iterator.
If an optional
The amount of subdivision of the curved segments is controlled
by the
Each call to this method returns a fresh
It is recommended, but not guaranteed, that objects
implementing the 
public boolean intersects(Rectangle2D r)
Shape intersects the
interior of a specified Rectangle2D .
The {@code Shape.intersects()} method allows a {@code Shape}
implementation to conservatively return {@code true} when:

public boolean intersects(double x, double y, double w, double h)
Shape intersects the
interior of a specified rectangular area.
The rectangular area is considered to intersect the Shape
if any point is contained in both the interior of the
Shape and the specified rectangular area.
The {@code Shape.intersects()} method allows a {@code Shape} implementation to conservatively return {@code true} when: 