uk.ac.starlink.ttools.plot2.layer

Class BinSizer

java.lang.Object

uk.ac.starlink.ttools.plot2.layer.BinSizer

@Equality
public abstract class BinSizer
extends Object

Determines 1-d histogram bin widths from data bounds.

Since:

8 Jan 2014

Author:

Mark Taylor

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	BinSizer.BinSizerSpecifier Specifier for BinSizer values.

Constructor Summary

Constructors

Constructor and Description
BinSizer()

Method Summary

Modifier and Type	Method and Description
static BinSizer	createCountBinSizer(double nbin) Returns a bin sizer instance which divides the axis range up into an approximately fixed number of equal intervals.
static BinSizer	createFixedBinSizer(double scaleWidth) Returns a bin sizer instance which always returns the same fixed value.
static ConfigKey<BinSizer>	createSizerConfigKey(ConfigMeta meta, ReportKey<Double> widthReportKey, int dfltNbin, boolean allowZero) Constructs a config key for acquiring BinSizers.
static String	getConfigKeyDescription() Returns an XML string describing in general terms how to operate the BinSizer config key.
abstract double	getScaleWidth(Scale scale, double dlo, double dhi, boolean rounded) Provides a bin width value in scale units for a given axis data range.

Methods inherited from class java.lang.Object

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

Constructor Detail

BinSizer

public BinSizer()

Method Detail

getScaleWidth

public abstract double getScaleWidth(Scale scale,
                                     double dlo,
                                     double dhi,
                                     boolean rounded)

Provides a bin width value in scale units for a given axis data range.

Parameters:

scale - axis scaling

dlo - data value lower bound

dhi - data value upper bound

rounded - if true, an attempt may be made to provide a width that corresponds to some kind of round number; this hint may be ignored

Returns:

scale interval appropriate for the given range

createFixedBinSizer

public static BinSizer createFixedBinSizer(double scaleWidth)

Returns a bin sizer instance which always returns the same fixed value. No rounding is performed.

Parameters:

scaleWidth - fixed bin width in scale units

Returns:

bin sizer

createCountBinSizer

public static BinSizer createCountBinSizer(double nbin)

Returns a bin sizer instance which divides the axis range up into an approximately fixed number of equal intervals. Rounding is performed on request, so that bin sizes are sensible values that give a bin count near the requested value.

Parameters:

nbin - number of intervals to divide the axis into

Returns:

bin sizer instance

createSizerConfigKey

public static ConfigKey<BinSizer> createSizerConfigKey(ConfigMeta meta,
                                                       ReportKey<Double> widthReportKey,
                                                       int dfltNbin,
                                                       boolean allowZero)

Constructs a config key for acquiring BinSizers.

Parameters:

meta - key metadata

widthReportKey - report key giving bin width in data coordinates

dfltNbin - default bin count

allowZero - true iff zero is an allowed width

Returns:

new config key

getConfigKeyDescription

public static String getConfigKeyDescription()

Returns an XML string describing in general terms how to operate the BinSizer config key.

Returns:

XML <p> element(s)