Package eu.webtoolkit.jwt.chart

Class WStandardColorMap

java.lang.Object

eu.webtoolkit.jwt.WObject

eu.webtoolkit.jwt.chart.WAbstractColorMap

eu.webtoolkit.jwt.chart.WStandardColorMap

public class WStandardColorMap
extends WAbstractColorMap

Standard colorMap.

The WStandardColorMap is defined by a list of value-to-color pairs. The WStandardColorMap has two modes: a continuous mode, in which the colors are linearly interpolated in between the pair values, and a non-continuous mode, where the values are not interpolated, so that the colormap has a banded effect. In non-continuous mode, the color of a given point P is the color of the pair with the largest value smaller than P.

Numerical values above the maximum value in the list map to the maximum value's color, all values below the minimum value in the list map to the minimum value's color. The range indicated by the minimum and maximum passed to the constructor determines which part of the colormap is drawn by createStrip() or paintLegend().

The figure below illustrates the possible colormaps that can be constructed from the list {"0.0 - StandardColor::DarkRed", "1.0 - StandardColor::Red", "2.0 - StandardColor::Gray"}. The discrete map (on the left) has the range [0, 3], the continuous map (on the right) has the range [0, 2]. The utility method discretise() is also applied to the continuous colormap to obtain a colormap with 5 bands in the same range.

Different uses of WStandardColorMap

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	WStandardColorMap.Pair	Contains a pair of a numerical value and a WColor.

Nested classes/interfaces inherited from class eu.webtoolkit.jwt.WObject

WObject.FormData

Field Summary

Fields inherited from class eu.webtoolkit.jwt.chart.WAbstractColorMap

format_, labelFont_, max_, min_, tickSpacing_

Constructor Summary

Constructors

Constructor	Description
WStandardColorMap(double min, double max, boolean continuous)	Construct a default colormap.
WStandardColorMap(double min, double max, java.util.List<WStandardColorMap.Pair> colors, boolean continuous)	Construct a custom colormap.

Method Summary

Modifier and Type	Method	Description
void	createStrip(WPainter painter, WRectF area)	Paints the colormap as a colored strip.
void	discretise(int numberOfBands)	Utility method to discretise a continuous colormap in a number of equally sized bands.
java.util.List<WStandardColorMap.Pair>	getColorValuePairs()
boolean	isContinuous()
void	paintLegend(WPainter painter, WRectF area)	Paints the colormap as a legend.
WColor	toColor(double value)	Converts a numerical value to a WColor.

Methods inherited from class eu.webtoolkit.jwt.chart.WAbstractColorMap

createStrip, getFormatString, getLabelFont, getMaximum, getMinimum, getTickSpacing, paintLegend, setFormatString, setLabelFont, setTickSpacing

Methods inherited from class eu.webtoolkit.jwt.WObject

getId, getObjectName, remove, setFormData, setObjectName, tr

Methods inherited from class java.lang.Object

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

Constructor Detail

WStandardColorMap

public WStandardColorMap(double min,
                         double max,
                         boolean continuous)

Construct a default colormap.

The default colormap is a transition from yellow to red. The color-scheme was taken from ColorBrewer, which contains lots of useful info and example schemes you might want to use for your custom colormaps.

WStandardColorMap

public WStandardColorMap(double min,
                         double max,
                         java.util.List<WStandardColorMap.Pair> colors,
                         boolean continuous)

Construct a custom colormap.

This constructor allows you to pass a list of value-to-color pairs that define a colormap as described in the class description.

Method Detail

discretise

public void discretise(int numberOfBands)

Utility method to discretise a continuous colormap in a number of equally sized bands.

This method makes a new list of value-to-color pairs by discretising the linear interpolation of the previous one into numberOfBands equally sized colorbands. This method only has effect if the colormap is continuous.

isContinuous

public boolean isContinuous()

getColorValuePairs

public java.util.List<WStandardColorMap.Pair> getColorValuePairs()

toColor

public WColor toColor(double value)

Description copied from class: WAbstractColorMap

Converts a numerical value to a WColor.

Specified by:

toColor in class WAbstractColorMap

createStrip

public void createStrip(WPainter painter,
                        WRectF area)

Description copied from class: WAbstractColorMap

Paints the colormap as a colored strip.

This paints the colormap from the minimum to the maximum value in the provided area (default = fill the entire paintdevice). This is no legend with ticks and labels, only the colors are painted.

Specified by:

createStrip in class WAbstractColorMap

See Also:

WAbstractColorMap.paintLegend(WPainter painter, WRectF area)

paintLegend

public void paintLegend(WPainter painter,
                        WRectF area)

Description copied from class: WAbstractColorMap

Paints the colormap as a legend.

The colormap is painted as a legend with ticks and value-labels. The parameter area can be used to specify a part of the paintdevice where the legend should be drawn. When drawing the legend, the tickspacing, labelformat and labelfont are taken into account.

Specified by:

paintLegend in class WAbstractColorMap

See Also:

WAbstractColorMap.setTickSpacing(int spacing), WAbstractColorMap.setFormatString(CharSequence format), WAbstractColorMap.setLabelFont(WFont font)