public interface Shape
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.
PathIterator
,
AffineTransform
,
FlatteningPathIterator
,
GeneralPath
Modifier and Type | Method and Description |
---|---|
boolean |
contains(double x,
double y)
Tests if the specified coordinates are inside the boundary of the
Shape , as described by the
definition of insideness. |
boolean |
contains(double x,
double y,
double w,
double h)
Tests if the interior of the
Shape entirely contains
the specified rectangular area. |
boolean |
contains(Point2D p)
Tests if a specified
Point2D is inside the boundary
of the Shape , as described by the
definition of insideness. |
boolean |
contains(Rectangle2D r)
Tests if the interior of the
Shape entirely contains the
specified Rectangle2D . |
Rectangle |
getBounds()
Returns an integer
Rectangle that completely encloses the
Shape . |
Rectangle2D |
getBounds2D()
Returns a high precision and more accurate bounding box of
the
Shape than the getBounds method. |
PathIterator |
getPathIterator(AffineTransform at)
Returns an iterator object that iterates along the
Shape boundary and provides access to the geometry of the
Shape outline. |
PathIterator |
getPathIterator(AffineTransform at,
double flatness)
Returns an iterator object that iterates along the
Shape
boundary and provides access to a flattened view of the
Shape outline geometry. |
boolean |
intersects(double x,
double y,
double w,
double h)
Tests if the interior of the
Shape intersects the
interior of a specified rectangular area. |
boolean |
intersects(Rectangle2D r)
Tests if the interior of the
Shape intersects the
interior of a specified Rectangle2D . |
Rectangle getBounds()
Rectangle
that completely encloses the
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 shape
may not be considered
contained in the returned bounds
object, but only in cases
where those points are also not considered contained in the original
shape
.
If a point
is inside the shape
according to the
contains(point)
method, then
it must be inside the returned Rectangle
bounds object
according to the contains(point)
method of the bounds
. Specifically:
shape.contains(x,y)
requires bounds.contains(x,y)
If a point
is not inside the shape
, then it might
still be contained in the bounds
object:
bounds.contains(x,y)
does not imply shape.contains(x,y)
Rectangle
that completely encloses
the Shape
.getBounds2D()
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 shape
may not be considered
contained in the returned bounds
object, but only in cases
where those points are also not considered contained in the original
shape
.
If a point
is inside the shape
according to the
contains(point)
method, then it must
be inside the returned Rectangle2D
bounds object according
to the contains(point)
method of the
bounds
. Specifically:
shape.contains(p)
requires bounds.contains(p)
If a point
is not inside the shape
, then it might
still be contained in the bounds
object:
bounds.contains(p)
does not imply shape.contains(p)
Rectangle2D
that is a
high-precision bounding box of the Shape
.getBounds()
boolean contains(double x, double y)
Shape
, as described by the
definition of insideness.x
- the specified X coordinate to be testedy
- the specified Y coordinate to be testedtrue
if the specified coordinates are inside
the Shape
boundary; false
otherwise.boolean contains(Point2D p)
Point2D
is inside the boundary
of the Shape
, as described by the
definition of insideness.p
- the specified Point2D
to be testedtrue
if the specified Point2D
is
inside the boundary of the Shape
;
false
otherwise.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 Shape.intersects()
method allows a Shape
implementation to conservatively return true
when:
Shape
intersect, but
Shapes
this method might
return true
even though the rectangular area does not
intersect the Shape
.
The Area
class performs
more accurate computations of geometric intersection than most
Shape
objects and therefore can be used if a more precise
answer is required.x
- the X coordinate of the upper-left corner
of the specified rectangular areay
- the Y coordinate of the upper-left corner
of the specified rectangular areaw
- the width of the specified rectangular areah
- the height of the specified rectangular areatrue
if the interior of the Shape
and
the interior of the rectangular area intersect, or are
both highly likely to intersect and intersection calculations
would be too expensive to perform; false
otherwise.Area
boolean intersects(Rectangle2D r)
Shape
intersects the
interior of a specified Rectangle2D
.
The Shape.intersects()
method allows a Shape
implementation to conservatively return true
when:
Rectangle2D
and the
Shape
intersect, but
Shapes
this method might
return true
even though the Rectangle2D
does not
intersect the Shape
.
The Area
class performs
more accurate computations of geometric intersection than most
Shape
objects and therefore can be used if a more precise
answer is required.r
- the specified Rectangle2D
true
if the interior of the Shape
and
the interior of the specified Rectangle2D
intersect, or are both highly likely to intersect and intersection
calculations would be too expensive to perform; false
otherwise.intersects(double, double, double, double)
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 Shape.contains()
method allows a Shape
implementation to conservatively return false
when:
intersect
method returns true
and
Shape
entirely contains the rectangular area are
prohibitively expensive.
Shapes
this method might
return false
even though the Shape
contains
the rectangular area.
The Area
class performs
more accurate geometric computations than most
Shape
objects and therefore can be used if a more precise
answer is required.x
- the X coordinate of the upper-left corner
of the specified rectangular areay
- the Y coordinate of the upper-left corner
of the specified rectangular areaw
- the width of the specified rectangular areah
- the height of the specified rectangular areatrue
if the interior of the Shape
entirely contains the specified rectangular area;
false
otherwise or, if the Shape
contains the rectangular area and the
intersects
method returns true
and the containment calculations would be too expensive to
perform.Area
,
intersects(double, double, double, double)
boolean contains(Rectangle2D r)
Shape
entirely contains the
specified Rectangle2D
.
The Shape.contains()
method allows a Shape
implementation to conservatively return false
when:
intersect
method returns true
and
Shape
entirely contains the Rectangle2D
are prohibitively expensive.
Shapes
this method might
return false
even though the Shape
contains
the Rectangle2D
.
The Area
class performs
more accurate geometric computations than most
Shape
objects and therefore can be used if a more precise
answer is required.r
- The specified Rectangle2D
true
if the interior of the Shape
entirely contains the Rectangle2D
;
false
otherwise or, if the Shape
contains the Rectangle2D
and the
intersects
method returns true
and the containment calculations would be too expensive to
perform.contains(double, double, double, double)
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 PathIterator
object that traverses the geometry of the Shape
object
independently from any other PathIterator
objects in use
at the same time.
It is recommended, but not guaranteed, that objects
implementing the Shape
interface isolate iterations
that are in process from any changes that might occur to the original
object's geometry during such iterations.
at
- an optional AffineTransform
to be applied to the
coordinates as they are returned in the iteration, or
null
if untransformed coordinates are desiredPathIterator
object, which independently
traverses the geometry of the Shape
.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 AffineTransform
is specified,
the coordinates returned in the iteration are transformed
accordingly.
The amount of subdivision of the curved segments is controlled
by the flatness
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.
Each call to this method returns a fresh PathIterator
object that traverses the Shape
object geometry
independently from any other PathIterator
objects in use at
the same time.
It is recommended, but not guaranteed, that objects
implementing the Shape
interface isolate iterations
that are in process from any changes that might occur to the original
object's geometry during such iterations.
at
- an optional AffineTransform
to be applied to the
coordinates as they are returned in the iteration, or
null
if untransformed coordinates are desiredflatness
- the maximum distance that the line segments used to
approximate the curved segments are allowed to deviate
from any point on the original curvePathIterator
that independently traverses
a flattened view of the geometry of the Shape
.
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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