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This charting library ${project.artifactId}- is an extension
in the spirit of Oracle's XYChart and performance/time-proven JDataViewer charting functionalities.
Emphasis was put on plotting performance for both large number of data points and real-time displays,
as well as scientific accuracies leading to error bar/surface plots, and other scientific plotting
features (parameter measurements, fitting, multiple axes, zoom, ...).
package de.gsi.chart.axes.spi.transforms;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import de.gsi.chart.axes.Axis;
import javafx.beans.property.DoubleProperty;
import javafx.beans.property.SimpleDoubleProperty;
/**
* @author rstein
*/
public class LogarithmicAxisTransform extends AbstractAxisTransform {
private static final Logger LOGGER = LoggerFactory.getLogger(LogarithmicAxisTransform.class);
public static final double DEFAULT_LOGARITHM_BASE = 10;
public static final double DEFAULT_LOG_MIN_VALUE = 1e-6;
public static final double DB20_LOGARITHM_BASE = Math.exp(Math.log10(10) / 20.0);
public static final double DB10_LOGARITHM_BASE = Math.exp(Math.log10(10) / 10.0);
// cached values -- for performance reasons
private double logarithmBaseCache = LogarithmicAxisTransform.DEFAULT_LOGARITHM_BASE;
private double logBaseCache = Math.log10(logarithmBaseCache);
private final DoubleProperty logarithmBase = new SimpleDoubleProperty(this, "logarithmBase", logarithmBaseCache) {
@Override
protected void invalidated() {
if (get() <= 1) {
throw new IllegalArgumentException("logarithmBase must be grater than 1");
}
logarithmBaseCache = get();
logBaseCache = Math.log10(logarithmBaseCache);
}
};
/**
* Base of the logarithm used by the axis, must be grater than 1.
*
* Default value: 10
*
*
* @return base of the logarithm
*/
public DoubleProperty logarithmBaseProperty() {
return logarithmBase;
}
/**
* Returns the value of the {@link #logarithmBaseProperty()}.
*
* @return base of the logarithm
*/
public double getLogarithmBase() {
return logarithmBase.get();
}
/**
* Sets value of the {@link #logarithmBaseProperty()}.
*
* @param value
* base of the logarithm, value > 1
*/
public void setLogarithmBase(final double value) {
logarithmBaseProperty().set(value);
}
protected double log(final double value) {
if (value <= 0) {
return Double.NaN;
// return rangeMin * 0.99;
}
return Math.log10(value) / logBaseCache;
}
protected double pow(final double value) {
return Math.pow(logarithmBaseCache, value);
}
@Override
public double forward(final double val) {
return log(val);
}
@Override
public double backward(final double val) {
return pow(val);
}
@Override
public void setMinimumRange(final double val) {
if (val <= 0) {
// reject
LogarithmicAxisTransform.LOGGER.warn(String.format("%s::setMinimumRange(%f) - rejected",
LogarithmicAxisTransform.class.getSimpleName(), val));
return;
}
axis.lowerBoundProperty().set(val);
}
@Override
public void setMaximumRange(final double val) {
if (val <= 0) {
// reject
LogarithmicAxisTransform.LOGGER.warn(String.format("%s::setMaximumRange(%f) - rejected",
LogarithmicAxisTransform.class.getSimpleName(), val));
return;
}
axis.upperBoundProperty().set(val);
}
@Override
public double getRoundedMinimumRange(final double min) {
return min <= 0 ? rangeMin : backward(Math.floor(forward(min)));
}
@Override
public double getRoundedMaximumRange(final double max) {
return backward(Math.ceil(forward(max)));
}
public LogarithmicAxisTransform(final Axis axis) {
super(axis);
rangeMin = LogarithmicAxisTransform.DEFAULT_LOG_MIN_VALUE;
}
}