public interface Shape
The 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
Rectangle getBounds()
Returns an integer 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()
Returns a high precision and more accurate bounding box of the 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)
Tests if the specified coordinates are inside the boundary of the 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)
Tests if a specified 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)
Tests if the interior of the 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)
Tests if the interior of the 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)
Tests if the interior of the Shape
entirely contains the specified rectangular area. All coordinates that lie inside the rectangular area must lie within the Shape
for the entire rectangular 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)
Tests if the interior of the 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)
Returns an iterator object that iterates along the 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)
Returns an iterator object that iterates along the 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
.
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