uk.ac.starlink.ttools.plot2.layer

Class XYArrayPlacement

java.lang.Object

uk.ac.starlink.ttools.plot2.layer.XYArrayPlacement

@Equality
public abstract class XYArrayPlacement
extends Object

Defines how to map an XYArrayData object to a definite position in data space.

Since:

18 Aug 2022

Author:

Mark Taylor

Field Summary

Fields

Modifier and Type	Field and Description
static XYArrayPlacement	INDEX Uses X,Y position at indicated fraction through arrays.
static XYArrayPlacement	XMAX Uses the position with the maximal X value.
static XYArrayPlacement	XMIN Uses the position with the minimal X value.
static XYArrayPlacement	XYMEAN Uses the center of gravity of all the (X,Y) values.
static XYArrayPlacement	YMAX Uses the position with the maximal Y value.
static XYArrayPlacement	YMIN Uses the position with the minimal Y value.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	XYArrayPlacement(String name, String description, boolean usesFraction) Constructor.

Method Summary

Modifier and Type	Method and Description
String	getDescription() Returns this placement policy's description.
String	getName() Returns this placement policy's name.
abstract boolean	readPosition(XYArrayData xyData, double fraction, double[] dpos) Attempts to determine the reference position of an XYArrayData object.
String	toString()
boolean	usesFraction() Indicates whether this placement pays attention to the value of the fraction parameter.

Methods inherited from class java.lang.Object

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

Field Detail

INDEX

public static final XYArrayPlacement INDEX

Uses X,Y position at indicated fraction through arrays.

XMAX

public static final XYArrayPlacement XMAX

Uses the position with the maximal X value.

XMIN

public static final XYArrayPlacement XMIN

Uses the position with the minimal X value.

YMAX

public static final XYArrayPlacement YMAX

Uses the position with the maximal Y value.

YMIN

public static final XYArrayPlacement YMIN

Uses the position with the minimal Y value.

XYMEAN

public static final XYArrayPlacement XYMEAN

Uses the center of gravity of all the (X,Y) values.

Constructor Detail

XYArrayPlacement

protected XYArrayPlacement(String name,
                           String description,
                           boolean usesFraction)

Constructor.

Parameters:

name - short name for presentation to users

description - XML-friendly description of behaviour

usesFraction - true iff this placement pays any attention to the value of the fraction parameter

Method Detail

getName

public String getName()

Returns this placement policy's name.

Returns:

name

getDescription

public String getDescription()

Returns this placement policy's description.

Returns:

XML-friendly description text

usesFraction

public boolean usesFraction()

Indicates whether this placement pays attention to the value of the fraction parameter.

Returns:

true if fraction may influence placement, false if it definitely doesn't

readPosition

public abstract boolean readPosition(XYArrayData xyData,
                                     double fraction,
                                     double[] dpos)

Attempts to determine the reference position of an XYArrayData object. On success, the position in data coordinates is written into the supplied 2-element array.

Parameters:

xyData - XY data, not null

fraction - numeric value in the range 0..1; may or may not be used

dpos - 2-element array for X, Y output on success

Returns:

true for success

toString

public String toString()

Overrides:

toString in class Object