Class ColorMapCSS

Object

ColorMap<String>

ColorMapCSS

public abstract class ColorMapCSS
extends ColorMap<String>

Coloring is a wrapper class for different schemes to map data onto colors for 2D visualizations using the HTML5 canvas element. Each inner class implements the ColorMap interface to provide an implementation agnostic manner to translate data into colors.

The following color mappings are currently available:

Index

Associates integer indices with colors.

Gradient1D

One dimensional color gradient spanning two or more colors.

Hue

Special case of Gradient1D where the gradient follows the color hue.

Gradient2D

Two dimensional gradient with each dimension represented by one color.

GradientND

Multi-dimensional gradient spanned by an identical number of colors

Author:

Christoph Hauert

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	ColorMapCSS.Gradient1D	One dimensional color gradient spanning two or more colors
static class	ColorMapCSS.Gradient2D	Two dimensional color gradient with one color for each dimension.
static class	ColorMapCSS.GradientND	N dimensional color gradient with one color for each dimension.
static class	ColorMapCSS.Hue	Color gradient following the hue.
static class	ColorMapCSS.Index	Associates integer indices with colors.

Nested classes/interfaces inherited from class ColorMap

ColorMap.Gradient<T>

Field Summary

Fields inherited from class ColorMap

INV255

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	ColorMapCSS()	Protected constructor to restrict instantiation to subclasses.

Method Summary

Modifier and Type	Method	Description
static String	Color2Css(Color color)	Convert Color to CSS style string.
static String[]	Color2Css(Color[] colors)	Convert an array of Color's to an array of CSS style strings.
static double	luminance(double[] color)	Compute the relative luminance of the color components in color.
static double	luminance(Color color)	Compute the relative luminance of color.
static double	luminance(String color)	Compute the relative luminance of the CSS color string color.
private static String	pad(String in)	Utility function to add padding (if needed) of leading zero'es to ensure that each color component is encoded by a two digit hexadecimal.
static String	RGB2Css(int r, int g, int b)	Convert the three components of a 24bit color, r, g, and b to a CSS color style.
static String	RGBA2Css(int r, int g, int b, int a)	Convert the four components of a 32bit color, r, g, b, and a to a CSS color style.
private static double	sRGBChannel2Intensity(double value)	Convert a gamma-encoded color component to linear light.

Methods inherited from class ColorMap

addAlpha, addAlpha, addColors, blendColors, blendColors, color2Color, translate, translate, translate, translate, translate

Methods inherited from class Object

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

Constructor Details

ColorMapCSS

protected ColorMapCSS()

Protected constructor to restrict instantiation to subclasses.

Method Details

Color2Css

public static String Color2Css(Color color)

Convert Color to CSS style string. For colors with transparency, the output is of the form rgba(r, g, b, a), where r, g, b, and a refer to the red, green, blue and alpha (transparency) components. Without transparency the output is of the form #rrggbb, where rr, gg, and bb are the hexadecimal representation of the red, green and blue components, respectively.

Parameters:

color - the color to convert

Returns:

CSS color string

See Also:

• RGBA2Css(int, int, int, int)
• RGB2Css(int, int, int)

Color2Css

public static String[] Color2Css(Color[] colors)

Convert an array of Color's to an array of CSS style strings.

Parameters:

colors - the array of Color's to convert

Returns:

array of CSS color strings

See Also:

• Color2Css(Color)

RGBA2Css

public static String RGBA2Css(int r,
 int g,
 int b,
 int a)

Convert the four components of a 32bit color, r, g, b, and a to a CSS color style.

Parameters:

r - the red component 0-255

g - the green component 0-255

b - the blue component 0-255

a - the alpha (transparency) component [0,1]

Returns:

CSS color string rgba(r, g, b, a)

RGB2Css

public static String RGB2Css(int r,
 int g,
 int b)

Convert the three components of a 24bit color, r, g, and b to a CSS color style.

Parameters:

r - the red component 0-255

g - the green component 0-255

b - the blue component 0-255

Returns:

CSS color string #rrggbb

luminance

public static double luminance(Color color)

Compute the relative luminance of color.

Colors with transparency are composited over white before computing luminance.

Parameters:

color - the color

Returns:

relative luminance in [0,1]

luminance

public static double luminance(String color)

Compute the relative luminance of the CSS color string color.

Parameters:

color - the CSS color string

Returns:

relative luminance in [0,1]

luminance

public static double luminance(double[] color)

Compute the relative luminance of the color components in color.

The array is interpreted as RGB or RGBA in [0,255]. If an alpha channel is present it is composited over white before computing luminance.

Parameters:

color - the RGB or RGBA channels

Returns:

relative luminance in [0,1]

pad

private static String pad(String in)

Utility function to add padding (if needed) of leading zero'es to ensure that each color component is encoded by a two digit hexadecimal.

Parameters:

in - the input string

Returns:

leading zero'es added as needed to ensure two digit string

sRGBChannel2Intensity

private static double sRGBChannel2Intensity(double value)

Convert a gamma-encoded color component to linear light.

Parameters:

value - the channel value in [0,1]

Returns:

linearized channel value