com.vividsolutions.jts.operation.buffer
Class BufferOp

java.lang.Object
  extended bycom.vividsolutions.jts.operation.buffer.BufferOp

public class BufferOp
extends java.lang.Object

Computes the buffer of a geometry, for both positive and negative buffer distances.

In GIS, the buffer of a geometry is defined as the Minkowski sum or difference of the geometry with a circle with radius equal to the absolute value of the buffer distance. In the CAD/CAM world buffers are known as offset curves.

Since true buffer curves may contain circular arcs, computed buffer polygons can only be approximations to the true geometry. The user can control the accuracy of the curve approximation by specifying the number of linear segments with which to approximate a curve.

The end cap style of a linear buffer may be specified. The following end cap styles are supported:

The computation uses an algorithm involving iterated noding and precision reduction to provide a high degree of robustness.

Version:
1.4.0

Field Summary
static int CAP_BUTT
          Specifies a butt (or flat) line buffer end cap style.
static int CAP_ROUND
          Specifies a round line buffer end cap style.
static int CAP_SQUARE
          Specifies a square line buffer end cap style.
 
Constructor Summary
BufferOp(Geometry g)
          Initializes a buffer computation for the given geometry
 
Method Summary
static Geometry bufferOp(Geometry g, double distance)
          Computes the buffer of a geometry for a given buffer distance.
static Geometry bufferOp(Geometry g, double distance, int quadrantSegments)
          Comutes the buffer for a geometry for a given buffer distance and accuracy of approximation.
 Geometry getResultGeometry(double distance)
          Returns the buffer computed for a geometry for a given buffer distance.
 Geometry getResultGeometry(double distance, int quadrantSegments)
          Deprecated. use setQuadrantSegments instead
 void setEndCapStyle(int endCapStyle)
          Specifies the end cap style of the generated buffer.
 void setQuadrantSegments(int quadrantSegments)
          Specifies the end cap style of the generated buffer.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

CAP_ROUND

public static final int CAP_ROUND
Specifies a round line buffer end cap style.

See Also:
Constant Field Values

CAP_BUTT

public static final int CAP_BUTT
Specifies a butt (or flat) line buffer end cap style.

See Also:
Constant Field Values

CAP_SQUARE

public static final int CAP_SQUARE
Specifies a square line buffer end cap style.

See Also:
Constant Field Values
Constructor Detail

BufferOp

public BufferOp(Geometry g)
Initializes a buffer computation for the given geometry

Parameters:
g - the geometry to buffer
Method Detail

bufferOp

public static Geometry bufferOp(Geometry g,
                                double distance)
Computes the buffer of a geometry for a given buffer distance.

Parameters:
g - the geometry to buffer
distance - the buffer distance
Returns:
the buffer of the input geometry

bufferOp

public static Geometry bufferOp(Geometry g,
                                double distance,
                                int quadrantSegments)
Comutes the buffer for a geometry for a given buffer distance and accuracy of approximation.

Parameters:
g - the geometry to buffer
distance - the buffer distance
quadrantSegments - the number of segments used to approximate a quarter circle
Returns:
the buffer of the input geometry

setEndCapStyle

public void setEndCapStyle(int endCapStyle)
Specifies the end cap style of the generated buffer. The styles supported are CAP_ROUND, CAP_BUTT, and CAP_SQUARE. The default is CAP_ROUND.

Parameters:
endCapStyle - the end cap style to specify

setQuadrantSegments

public void setQuadrantSegments(int quadrantSegments)
Specifies the end cap style of the generated buffer. The styles supported are CAP_ROUND, CAP_BUTT, and CAP_SQUARE. The default is CAP_ROUND.


getResultGeometry

public Geometry getResultGeometry(double distance)
Returns the buffer computed for a geometry for a given buffer distance.

Parameters:
distance - the buffer distance
Returns:
the buffer of the input geometry

getResultGeometry

public Geometry getResultGeometry(double distance,
                                  int quadrantSegments)
Deprecated. use setQuadrantSegments instead

Comutes the buffer for a geometry for a given buffer distance and accuracy of approximation.

Parameters:
distance - the buffer distance
quadrantSegments - the number of segments used to approximate a quarter circle
Returns:
the buffer of the input geometry