Class ColorUtils
Color math utility functions
Inherited Members
Namespace: NixUniversalSDK
Assembly: NixUniversalSDK.dll
Syntax
public static class ColorUtils
Methods
AdaptXyz(double[], double[], double[])
Adapts colour in XYZ from one reference white to another using Bradford adaptation method. NOTE: refIn, refOut, xyzIn must all be on the same scale
Declaration
public static double[] AdaptXyz(double[] xyzIn, double[] refIn, double[] refOut)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyzIn | Source color, referenced to refIn (element order X, Y, Z) |
| double[] | refIn | Source reference white (element order X, Y, Z) |
| double[] | refOut | Destination reference white (element order X, Y, Z) |
Returns
| Type | Description |
|---|---|
| double[] | Adapted color, referenced to refOut (element order X, Y, Z) |
ClipXyz(double[], double[])
Clips CIEXYZ values in between 0 and the value of the reference white to ensure X, Y, Z are in the proper range.
Declaration
public static double[] ClipXyz(double[] xyz, double[] xyzRef)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyz | CIEXYZ value (element order X, Y, Z) |
| double[] | xyzRef | CIEXYZ value for reference white (X, Y, Z) |
Returns
| Type | Description |
|---|---|
| double[] | Clipped CIEXYZ value (element order X, Y, Z) |
CmykToXyz(double[], double[], bool)
Calculates XYZ value from CMYK input using built-in lookup tables
Declaration
public static double[] CmykToXyz(double[] cmykIn, double[] refOut, bool bpc)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | cmykIn | CMYK colour input, unity scale (element order C, M, Y, K) |
| double[] | refOut | Reference white value for XYZ output, unity scale (element order X, Y, Z) |
| bool | bpc | Set to true to perform black point compensation |
Returns
| Type | Description |
|---|---|
| double[] | XYZ value output, unity scale (element order X, Y, Z) |
CmykToXyz(double[], double[], bool, double[][], int[][], int[][], int[][])
Calculates XYZ value from CMYK input using lookup tables provided as input arguments
Declaration
public static double[] CmykToXyz(double[] cmykIn, double[] refOut, bool bpc, double[][] m, int[][] input, int[][] clut, int[][] output)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | cmykIn | CMYK colour input, unity scale (element order C, M, Y, K) |
| double[] | refOut | Reference white value for XYZ output, unity scale (element order X, Y, Z) |
| bool | bpc | Set to true to perform black point compensation |
| double[][] | m | 3x3 Extracted from ICC profile: transformation matrix to perform on LAB value (NOT used in current function) |
| int[][] | input | 256x4 Extracted from ICC profile: InputCurves |
| int[][] | clut | 6561x3 Extracted from ICC profile: CMYK to LAB LUT (flattened 9x9x9x9 array with 3 channels, one each for L, A, B) |
| int[][] | output | Extracted from ICC profile: OutputCurves (NOT used in current function, default profile has 1:1 output) |
Returns
| Type | Description |
|---|---|
| double[] | XYZ value output, unity scale (element order X, Y, Z) |
DegToRad(double)
Converts angle in degrees to radians (used in dE2000 function)
Declaration
public static double DegToRad(double deg)
Parameters
| Type | Name | Description |
|---|---|---|
| double | deg | Angle in degrees |
Returns
| Type | Description |
|---|---|
| double | Angle in radians |
DeltaE00(double[], double[], double, double, double)
Takes two CIELAB values and calculates color difference (dE) using the CIE2000 formula. NOTE: both CIELAB values must share the same reference white. If they do not, convert to XYZ, adapt, convert back to CIELAB before calculating dE.
Declaration
public static double DeltaE00(double[] lab1, double[] lab2, double kL = 1, double kC = 1, double kH = 1)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lab1 | First CIELAB value (element order L, a, b) |
| double[] | lab2 | Second CIELAB value (element order L, a, b) |
| double | kL | Model parameter (optional, default 1) |
| double | kC | Model parameter (optional, default 1) |
| double | kH | Model parameter (optional, default 1) |
Returns
| Type | Description |
|---|---|
| double | Delta E (2000) value |
DeltaE76(double[], double[])
Takes two CIELAB values and calculates color difference (dE) using CIE1976 formula. NOTE: both CIELAB values must share the same reference white. If they do not: convert to XYZ, adapt, convert back to CIELAB before calculating dE.
Declaration
public static double DeltaE76(double[] lab1, double[] lab2)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lab1 | First CIELAB value (element order L, a, b) |
| double[] | lab2 | Second CIELAB value (element order L, a, b) |
Returns
| Type | Description |
|---|---|
| double | Delta E (1976) value |
DeltaE94(double[], double[], double, double, double)
Takes two CIELAB values and calculates color difference (dE) using the CIE1994 formula. Requires weighting factors kL, k1, and k2 which are dependent on application. Use DeltaE94G(double[], double[]) for graphic design applications andDeltaE94T(double[], double[]) for textile applications. Both CIELAB values must share the same reference white.If they do not, convert to XYZ, adapt, convert back to CIELAB before calculating dE.
Declaration
public static double DeltaE94(double[] lab1, double[] lab2, double kL, double k1, double k2)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lab1 | First CIELAB value (element order L, a, b) |
| double[] | lab2 | Second CIELAB value (element order L, a, b) |
| double | kL | Weighting factor (application dependent) |
| double | k1 | Weighting factor (application dependent) |
| double | k2 | Weighting factor (application dependent) |
Returns
| Type | Description |
|---|---|
| double | Delta E (1994) value |
DeltaE94G(double[], double[])
Takes two CIELAB values and calculates color difference (dE) using the CIE1994 formula for the graphic design application (kL = 1, k1 = 0.045, k2 = 0.015). See also DeltaE94(double[], double[], double, double, double)
Declaration
public static double DeltaE94G(double[] lab1, double[] lab2)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lab1 | First CIELAB value (element order L, a, b) |
| double[] | lab2 | Second CIELAB value (element order L, a, b) |
Returns
| Type | Description |
|---|---|
| double | Delta E (1994) value |
DeltaE94T(double[], double[])
Takes two CIELAB values and calculates color difference (dE) using the CIE1994 formula for the textiles design application (kL = 2, k1 = 0.048, k2 = 0.014). See also DeltaE94(double[], double[], double, double, double)
Declaration
public static double DeltaE94T(double[] lab1, double[] lab2)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lab1 | First CIELAB value (element order L, a, b) |
| double[] | lab2 | Second CIELAB value (element order L, a, b) |
Returns
| Type | Description |
|---|---|
| double | Delta E (1994) value |
DeltaECmc(double[], double[], double, double)
Takes two CIELAB values and calculates color difference (dE) using the CMC(l:c) formula. Depends on model parameters l and c; common values used are CMC(2:1) for acceptability and CMC(1:1) for perceptibility.
Declaration
public static double DeltaECmc(double[] lab1, double[] lab2, double l, double c)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lab1 | First CIELAB value (element order L, a, b) |
| double[] | lab2 | First CIELAB value (element order L, a, b) |
| double | l | Model parameter l |
| double | c | Model parameter c |
Returns
| Type | Description |
|---|---|
| double | Delta E (CMC) value |
LabToLch(double[])
Takes CIELAB value and converts to polar coordinates (LCH)
Declaration
public static double[] LabToLch(double[] labIn)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | labIn | CIELAB value (element order L, a, b) |
Returns
| Type | Description |
|---|---|
| double[] | LCHab value (element order L, c, h). Hue angle h is in degrees |
LabToXyz(double[], Illuminant, Observer)
Takes CIELAB value and its reference white to calculate CIEXYZ value
Declaration
public static double[] LabToXyz(double[] lab, Illuminant illuminant, Observer observer)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lab | |
| Illuminant | illuminant | Illuminant for reference white point |
| Observer | observer | Observer for reference white point |
Returns
| Type | Description |
|---|---|
| double[] | CIEXYZ value (element order X, Y, Z) |
LabToXyz(double[], ReferenceWhite)
Takes CIELAB value and its reference white to calculate CIEXYZ value
Declaration
public static double[] LabToXyz(double[] lab, ReferenceWhite reference)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lab | CIELAB value (element order L, a, b) |
| ReferenceWhite | reference | Reference white point for input CIEXYZ value |
Returns
| Type | Description |
|---|---|
| double[] | CIEXYZ value (element order X, Y, Z) |
LabToXyz(double[], double[])
Takes CIELAB value and its reference white to calculate CIEXYZ value
Declaration
public static double[] LabToXyz(double[] lab, double[] xyzRef)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lab | CIELAB value (element order L, a, b) |
| double[] | xyzRef | Reference white (element order X, Y, Z) |
Returns
| Type | Description |
|---|---|
| double[] | CIEXYZ value (element order X, Y, Z) |
LchToLab(double[])
Takes LCHab value and converts to CIELAB
Declaration
public static double[] LchToLab(double[] lchIn)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lchIn | LCHab value (element order L, c, h). Hue angle h is in degrees |
Returns
| Type | Description |
|---|---|
| double[] | CIELAB value (element order L, a, b) |
LchToLuv(double[])
Takes LCHuv value and converts to CIELUV
Declaration
public static double[] LchToLuv(double[] lchIn)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | lchIn | LCHuv value (element order L, c, h). Hue angle h is in degrees |
Returns
| Type | Description |
|---|---|
| double[] | CIELUV value (element order L, u, v) |
LuvToLch(double[])
Takes CIELUV value and converts to polar coordinates (LCH)
Declaration
public static double[] LuvToLch(double[] LuvIn)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | LuvIn | CIELUV value (element order L, u, v) |
Returns
| Type | Description |
|---|---|
| double[] | LCHuv value (element order L, c, h). Hue angle h is in degrees |
LuvToXyz(double[], double[])
Takes CIELUV value and its reference white to calculate CIEXYZ value
Declaration
public static double[] LuvToXyz(double[] luvIn, double[] xyzRef)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | luvIn | CIELUV value (element order L, u, v) |
| double[] | xyzRef | CIEXYZ reference white (element order X, Y, Z) |
Returns
| Type | Description |
|---|---|
| double[] | CIEXYZ value (element order X, Y, Z) |
RadToDeg(double)
Converts angle in radians to degrees (used in dE2000 function)
Declaration
public static double RadToDeg(double rads)
Parameters
| Type | Name | Description |
|---|---|---|
| double | rads | Angle in radians |
Returns
| Type | Description |
|---|---|
| double | Angle in degrees |
RgbToXyz(double[], double[], double[], double[], double[], double[])
Calculates XYZ from linear RGB given chromaticity coordinates of RGB working space primaries and reference whites of RGB and XYZ value.
Declaration
public static double[] RgbToXyz(double[] rgbIn, double[] rC, double[] gC, double[] bC, double[] wC, double[] refOut)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | rgbIn | Input linear RGB value, unity scale (element order R, G, B) |
| double[] | rC | RGB space red primary chromaticity coordinates (element order x, y) |
| double[] | gC | RGB space green primary chromaticity coordinates (element order x, y) |
| double[] | bC | RGB space blue primary chromaticity coordinates (element order x, y) |
| double[] | wC | RGB space reference white/grey chromaticity coordinates (element order x, y) |
| double[] | refOut | Selected reference white of output XYZ color, unity scale (element order X, Y, Z) |
Returns
| Type | Description |
|---|---|
| double[] | XYZ value, unity scale, with reference white refOut (element order X, Y, Z) |
RgbTripletToHexString(byte[])
Takes a RGB triplet and formats it as a HEX string (e.g. - "#RRGGBB")
Declaration
public static string RgbTripletToHexString(byte[] rgb)
Parameters
| Type | Name | Description |
|---|---|---|
| byte[] | rgb |
Returns
| Type | Description |
|---|---|
| string |
Exceptions
| Type | Condition |
|---|---|
| ArgumentException | Thrown if array does not have three entries |
SRgbToXyz(byte[], double[])
Calculates XYZ from sRGB value
Declaration
public static double[] SRgbToXyz(byte[] sRgb, double[] refOut)
Parameters
| Type | Name | Description |
|---|---|---|
| byte[] | sRgb | Non-linear sRGB value, 0 - 255 scale (element order R, G, B) |
| double[] | refOut |
|
Returns
| Type | Description |
|---|---|
| double[] | XYZ value, unity scale, with reference white refOut (element order X, Y, Z) |
Spectral10ToDensity(int[], float[], DensityStatus)
Takes reflectance data on 10 nm intervals and calculates CMYK densities according to ISO 5-3:2009. Data must be provided on 10 nm intervals corresponding to the nearest 10 nanometer. Density values are calculated across the range 340 - 770 nm. If the provided data spans a shorter range (e.g. - 400 - 700 nm), the values at the boundaries are repeated.
Declaration
public static double[] Spectral10ToDensity(int[] lambda, float[] reflectance, DensityStatus status)
Parameters
| Type | Name | Description |
|---|---|---|
| int[] | lambda | Wavelength values of provided reflectance data. |
| float[] | reflectance | Reflectance data. Must contain the same number of elements as lambda |
| DensityStatus | status | Selected density status |
Returns
| Type | Description |
|---|---|
| double[] | CMYK densities (element order C, M, Y, K) |
Spectral10ToXyz(int[], float[], Illuminant, Observer)
Takes reflectance data on 10 nm intervals and calculates a CIEXYZ value according to ASTM E308. Data must be provided on 10 nm intervals corresponding to the nearest 10 nanometer. CIEXYZ values are calculated across the range 360 - 780 nm.If the provided data spans a shorter range (e.g. - 400 - 700 nm), the values at the boundaries are repeated.
Declaration
public static double[] Spectral10ToXyz(int[] lambda, float[] reflectance, Illuminant illuminant, Observer observer)
Parameters
| Type | Name | Description |
|---|---|---|
| int[] | lambda | Wavelength values of provided reflectance data. |
| float[] | reflectance | Reflectance data. Must contain the same number of elements as lambda |
| Illuminant | illuminant | Reference illuminant |
| Observer | observer | Reference observer |
Returns
| Type | Description |
|---|---|
| double[] | CIEXYZ value reported on 0 - 1.0 scale (element order X, Y, Z) |
Spectral10ToXyz(int[], float[], ReferenceWhite)
Takes reflectance data on 10 nm intervals and calculates a CIEXYZ value according to ASTM E308. Data must be provided on 10 nm intervals corresponding to the nearest 10 nanometer. CIEXYZ values are calculated across the range 360 - 780 nm. If the provided data spans a shorter range (e.g. - 400 - 700 nm), the values at the boundaries are repeated.
Declaration
public static double[] Spectral10ToXyz(int[] lambda, float[] reflectance, ReferenceWhite reference)
Parameters
| Type | Name | Description |
|---|---|---|
| int[] | lambda | Wavelength values of provided reflectance data. |
| float[] | reflectance | Reflectance data. Must contain the same number of elements as lambda |
| ReferenceWhite | reference | Selected reference white |
Returns
| Type | Description |
|---|---|
| double[] | CIEXYZ value reported on 0 - 1.0 scale (element order X, Y, Z) |
XyzChromaticity(double[])
Calculates chromaticity coordinates x,y from a given xyz value. WARNING: Be aware that for black xyz(0, 0, 0), the result is undefined. For this case, use chromaticity of reference white instead.
Declaration
public static double[] XyzChromaticity(double[] xyz)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyz | Source color (element order X, Y, Z) |
Returns
| Type | Description |
|---|---|
| double[] | Chromaticity of input color, unity scale (element order x, y) |
XyzToCmyk(double[], double[], bool)
Calculates CMYK value from XYZ input using built in lookup tables
Declaration
public static double[] XyzToCmyk(double[] xyzIn, double[] xyzRef, bool bpc)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyzIn | XYZ colour, unity scale (element order X, Y, Z) |
| double[] | xyzRef | Reference white value for xyzIn, unity scale (element order X, Y, Z) |
| bool | bpc | Black point compensation enabled / disabled |
Returns
| Type | Description |
|---|---|
| double[] | CMYK value on unity scale (element order C, M, Y, K) |
XyzToCmyk(double[], double[], bool, double[][], int[][], int[][], int[][])
Calculates CMYK value from XYZ using lookup tables provided as inputCurves arguments
Declaration
public static double[] XyzToCmyk(double[] xyzIn, double[] xyzRef, bool bpc, double[][] m, int[][] inputCurves, int[][] clut, int[][] outputCurves)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyzIn | XYZ colour, unity scale (element order X, Y, Z) |
| double[] | xyzRef | Reference white value for xyzIn, unity scale (element order X, Y, Z) |
| bool | bpc | Black point compensation enabled / disabled |
| double[][] | m | 3x3 Extracted from ICC profile: transformation matrix to perform on LAB value (code only tested with identity matrix) |
| int[][] | inputCurves | 256x3 Extracted from ICC profile: InputCurves |
| int[][] | clut | 35937x4: Extracted from ICC profile: Lab to CMYK LUT (flattened 33x33x33 array with 4 channels, one each for C,M,Y,K) |
| int[][] | outputCurves | 256x4: Extracted from ICC profile: OutputCurves |
Returns
| Type | Description |
|---|---|
| double[] | CMYK value on unity scale (element order C, M, Y, K) |
XyzToLab(double[], Illuminant, Observer)
Takes CIEXYZ value and its reference white to calculate CIELAB value. Value xyz and xyzRef must be either unity (Y on 0 - 1) input.
Declaration
public static double[] XyzToLab(double[] xyz, Illuminant illuminant, Observer observer)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyz | |
| Illuminant | illuminant | Illuminant for reference white point |
| Observer | observer | Observer for reference white point |
Returns
| Type | Description |
|---|---|
| double[] | CIELAB value (element order L, a, b) |
XyzToLab(double[], ReferenceWhite)
Takes CIEXYZ value and its reference white to calculate CIELAB value. Value xyz and xyzRef must be either unity (Y on 0 - 1) input.
Declaration
public static double[] XyzToLab(double[] xyz, ReferenceWhite reference)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyz | CIEXYZ value (element order X, Y, Z) |
| ReferenceWhite | reference | Reference white point for input CIEXYZ value |
Returns
| Type | Description |
|---|---|
| double[] | CIELAB value (element order L, a, b) |
XyzToLab(double[], double[])
Takes CIEXYZ value and its reference white to calculate CIELAB value. Values xyz and xyzRef can be either unity (0 - 1) or scaled (0 - 100) input, but both vectors must be the same scale. (i.e., if xyz is unity scale, xyzRef must also be unity scale)
Declaration
public static double[] XyzToLab(double[] xyz, double[] xyzRef)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyz | CIEXYZ value (element order X, Y, Z) |
| double[] | xyzRef | CIEXYZ value for reference white (X, Y, Z) |
Returns
| Type | Description |
|---|---|
| double[] | CIELAB value (element order L, a, b) |
XyzToLuv(double[], double[])
Takes CIEXYZ value and its reference white to calculate CIELUV value.
Declaration
public static double[] XyzToLuv(double[] xyzIn, double[] xyzRef)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyzIn | CIEXYZ value (element order X, Y, Z) |
| double[] | xyzRef | CIEXYZ reference white (element order X, Y, Z) |
Returns
| Type | Description |
|---|---|
| double[] | CIELUV value (element order L, u, v) |
XyzToRgb(double[], double[], double[], double[], double[], double[])
Calculates linear RGB from XYZ given chromaticity coordinates of RGB working space primaries and reference whites of RGB and XYZ value
Declaration
public static double[] XyzToRgb(double[] xyzIn, double[] refIn, double[] rC, double[] gC, double[] bC, double[] wC)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyzIn | Input colour XYZ values, unity scale (element order X, Y, Z) |
| double[] | refIn | Reference white of input colour xyzIn, unity scale (element order X, Y, Z) |
| double[] | rC | RGB space red primary chromaticity coordinates (element order x, y) |
| double[] | gC | RGB space green primary chromaticity coordinates (element order x, y) |
| double[] | bC | RGB space blue primary chromaticity coordinates (element order x, y) |
| double[] | wC | RGB space reference white/grey chromaticity coordinates (element order x, y) |
Returns
| Type | Description |
|---|---|
| double[] |
XyzToSRgb(double[], double[])
Calculates companded sRGB value from XYZ given reference white of XYZ value.
Declaration
public static byte[] XyzToSRgb(double[] xyzIn, double[] refIn)
Parameters
| Type | Name | Description |
|---|---|---|
| double[] | xyzIn | Input colour XYZ values, unity scale (element order X, Y, Z) |
| double[] | refIn | Reference white of input colour xyzIn, unity scale (element order X, Y, Z) |
Returns
| Type | Description |
|---|---|
| byte[] | Non-linear sRGB value, 0 - 255 scale (element order R, G, B) |