Package org.tinfour.contour

Class Contour

java.lang.Object

org.tinfour.contour.Contour

public class Contour
extends Object

Provides methods and elements for constructing a contour. Tinfour defines contours as specifying a boundary between two regions in a plane. The region to the left of the contour is treated as including points with vertical coordinates greater than or equal to the contour's vertical coordinate. The values to the right are treated as including points with vertical coordinates less than the contour's vertical coordinate. Thus, in an elevation set, a hill would be represented with a set of closed-loop contours taken in counterclockwise order. A valley would be represented as a set of closed-loop contours taken in clockwise order.

The complete() method should always be called when a contour is fully populated (e.g. it is complete). The complete call trims the internal buffers and performs any sanity checking required for contour management.

A closed-loop contour is expected to always include a "closure point" so that the first point in the contour matches the last. This approach is taken to simplify internal logic in the contour building routines. The complete() method ensures that a closure point is added to closed-loop contours if none is provided by the application.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	Contour.ContourType	An enumeration that indicates the type of a contour

Constructor Summary

Constructors

Constructor	Description
Contour(int leftIndex, int rightIndex, double z, boolean closedLoop)	Constructs an instance of a contour

Method Summary

Modifier and Type	Method	Description
void	add(double x, double y)	Add an coordinate point to the contour.
void	complete()	Called when the construction of a contour is complete to trim the memory for the internal point collection.
Rectangle2D	getBounds()	Get the bounds of the contour.
int	getContourId()	Gets the serialized identification code for the contour.
int	getContourIndex()	Gets the index for the value of the input contour array that was used to build this contour, or a notional value if this instance is a boundary contour.
Contour.ContourType	getContourType()	Indicates whether the contour is an interior or perimeter contour.
double[]	getCoordinates()	Gets a safe copy of the coordinates for the contour.
int	getLeftIndex()	Get the index for the region lying to the left of the contour.
Path2D	getPath2D(AffineTransform transform)	Gets a Path2D suitable for rendering purposes.
int	getRightIndex()	Get the index for the region lying to the right of the contour.
double[]	getXY()	Gets a safe copy of the coordinates for the contour.
double	getZ()	Gets the z value associated with the contour
boolean	isBoundary()	Indicates whether the contour is a boundary contour.
boolean	isClosed()	Indicates that the contour forms a closed loop
boolean	isEmpty()	Indicates whether the contour is empty.
int	size()	Indicates the number of points stored in the contour
String	toString()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

Contour

public Contour(int leftIndex,
               int rightIndex,
               double z,
               boolean closedLoop)

Constructs an instance of a contour

Parameters:

leftIndex - the contour-interval index of the area to the left of the contour.

rightIndex - the contour-interval index of the area to the right of the contour.

z - the vertical coordinate for the contour

closedLoop - indicates if the contour is to be treated as a closed loop.

Method Detail

add

public void add(double x,
                double y)

Add an coordinate point to the contour.

Parameters:

x - the Cartesian x-coordinate for the point

y - the Cartesian y-coordinate for the point

getCoordinates

public double[] getCoordinates()

Gets a safe copy of the coordinates for the contour. This method is scheduled for replacement in a future release. Please use getXY().

Returns:

a valid, potentially zero-length array giving x and y coordinates for a series of points.

getXY

public double[] getXY()

Gets a safe copy of the coordinates for the contour. Coordinates are stored in a one-dimensional array of doubles in the order:

 { (x0,y0), (x1,y1), (x2,y2), etc. }.

Returns:

a valid, potentially zero-length array giving x and y coordinates for a series of points.

getZ

public double getZ()

Gets the z value associated with the contour

Returns:

the z value used to construct the contour.

isEmpty

public boolean isEmpty()

Indicates whether the contour is empty.

Returns:

true if the contour has no geometry defined; otherwise false.

size

public int size()

Indicates the number of points stored in the contour

Returns:

a positive integer value, potentially zero.

complete

public void complete()

Called when the construction of a contour is complete to trim the memory for the internal point collection. This method also ensures that a closed-loop contour includes a closure point.

References to edges and contour-building elements are not affected by this call.

getContourId

public int getContourId()

Gets the serialized identification code for the contour. When used with the ContourBuilder, this value gives a unique serial ID assigned when the contour is constructed. This value should not be confused with the contour interval or the left and right side index values.

Returns:

an integer value.

getPath2D

public Path2D getPath2D(AffineTransform transform)

Gets a Path2D suitable for rendering purposes.

Parameters:

transform - a valid AffineTransform, typically specified to map the Cartesian coordinates of the contour to pixel coordinate.

Returns:

a valid instance

getContourType

public Contour.ContourType getContourType()

Indicates whether the contour is an interior or perimeter contour. Note: future implementations may include additional types.

Returns:

a valid enumeration instance

isBoundary

public boolean isBoundary()

Indicates whether the contour is a boundary contour.

Returns:

true if the contour is a boundary; otherwise, false.

isClosed

public boolean isClosed()

Indicates that the contour forms a closed loop

Returns:

true if the contour forms a closed loop; otherwise false

getBounds

public Rectangle2D getBounds()

Get the bounds of the contour.

Returns:

a valid instance.

toString

public String toString()

Overrides:

toString in class Object

getContourIndex

public int getContourIndex()

Gets the index for the value of the input contour array that was used to build this contour, or a notional value if this instance is a boundary contour.

It is strongly recommended that application code check to see if this instance is a boundary contour before using the contour index.

Returns:

a value in the range 0 to the length of the input z contour array.

getLeftIndex

public int getLeftIndex()

Get the index for the region lying to the left of the contour.

Returns:

an integer in the range 0 to nContour, or -1 if the contour borders a null-data area

getRightIndex

public int getRightIndex()

Get the index for the region lying to the right of the contour.

Returns:

an integer in the range 0 to nContour, or -1 if the contour borders a null-data area