Struct LabColor

Namespace

Egami.Colors

Assembly

Egami.dll

A CIE Lab* color relative to D50, as ICC and CSS Color 4 define Lab.

public readonly record struct LabColor : IColorValue<LabColor>, IEquatable<LabColor>

Implements

IColorValue<LabColor>

IEquatable<LabColor>

Inherited Members

ValueType.Equals(object)

ValueType.GetHashCode()

ValueType.ToString()

object.Equals(object, object)

object.GetType()

object.ReferenceEquals(object, object)

Examples

// Color values in the models apps ask for, from and to pixels, and between each other.
Rgba8 orange = new(240, 128, 32, 255);
HslColor hsl = HslColor.From(orange);                          // hue 28°, saturation 0.87, lightness 0.53
LabColor lab = ColorConvert.Convert<HslColor, LabColor>(hsl);  // through XYZ
OklchColor oklch = OklchColor.From(orange);
YCbCrColor jpeg = YCbCrColor.From(orange);                     // BT.601 full range, as JPEG
YCbCrColor video = YCbCrColor.From(orange, YuvMatrix.Bt709, YuvRange.Limited);

// Color difference: CIEDE2000 on Lab, distance on Oklab.
double deltaE = lab.DeltaE2000(LabColor.From(new Rgba8(235, 130, 40, 255)));

// Whole rows at once, from any pixel type and encoding.
Rgba8[] pixels = [orange, new(10, 20, 30, 255)];
OklabColor[] row = new OklabColor[pixels.Length];
ColorConvert.FromPixels<Rgba8, OklabColor>(pixels, row);
ColorConvert.FromPixels<Rgba8, OklabColor>(pixels, row, ColorProfile.DisplayP3);   // the same pixels read as Display P3

Constructors

LabColor(float, float, float)

A CIE Lab* color relative to D50, as ICC and CSS Color 4 define Lab.

public LabColor(float L, float A, float B)

Parameters

L float

Lightness, 0 for black to 100 for white.

A float

Green (negative) to red (positive), about −128 to 127 for real colors.

B float

Blue (negative) to yellow (positive), about −128 to 127 for real colors.

Examples

// Color values in the models apps ask for, from and to pixels, and between each other.
Rgba8 orange = new(240, 128, 32, 255);
HslColor hsl = HslColor.From(orange);                          // hue 28°, saturation 0.87, lightness 0.53
LabColor lab = ColorConvert.Convert<HslColor, LabColor>(hsl);  // through XYZ
OklchColor oklch = OklchColor.From(orange);
YCbCrColor jpeg = YCbCrColor.From(orange);                     // BT.601 full range, as JPEG
YCbCrColor video = YCbCrColor.From(orange, YuvMatrix.Bt709, YuvRange.Limited);

// Color difference: CIEDE2000 on Lab, distance on Oklab.
double deltaE = lab.DeltaE2000(LabColor.From(new Rgba8(235, 130, 40, 255)));

// Whole rows at once, from any pixel type and encoding.
Rgba8[] pixels = [orange, new(10, 20, 30, 255)];
OklabColor[] row = new OklabColor[pixels.Length];
ColorConvert.FromPixels<Rgba8, OklabColor>(pixels, row);
ColorConvert.FromPixels<Rgba8, OklabColor>(pixels, row, ColorProfile.DisplayP3);   // the same pixels read as Display P3

Properties

A

Green (negative) to red (positive), about −128 to 127 for real colors.

public float A { get; init; }

Property Value

float

B

Blue (negative) to yellow (positive), about −128 to 127 for real colors.

public float B { get; init; }

Property Value

float

L

Lightness, 0 for black to 100 for white.

public float L { get; init; }

Property Value

float

Methods

DeltaE2000(LabColor)

Returns the CIEDE2000 color difference (CIE 142-2001), the industry's measure of how different two colors look: under 1 is barely visible, 2 is noticeable side by side.

public double DeltaE2000(LabColor other)

Parameters

other LabColor

The other color.

Returns

double

ΔE₀₀, 0 or more.

From(Rgba8)

Returns the value of an sRGB pixel; alpha is ignored.

public static LabColor From(Rgba8 color)

Parameters

color Rgba8

The pixel.

Returns

LabColor

The value.

From(RgbaF32)

Returns the value of an sRGB pixel, whose channels may be outside 0..1; alpha is ignored.

public static LabColor From(RgbaF32 color)

Parameters

color RgbaF32

The pixel.

Returns

LabColor

The value.

FromXyz(XyzColor)

Returns the value for an XYZ color (D65, white Y = 1).

public static LabColor FromXyz(XyzColor xyz)

Parameters

xyz XyzColor

The color.

Returns

LabColor

The value; components may fall outside their usual range for colors outside sRGB.

IsCloseTo(LabColor, float)

Returns whether every component of the two values differs by at most tolerance.

public bool IsCloseTo(LabColor other, float tolerance = 0.0001)

Parameters

other LabColor

The other value.

tolerance float

The largest difference allowed in a component.

Returns

bool

true if they are that close.

ToRgba8()

Returns the color as an opaque sRGB pixel, each channel clamped into range.

public Rgba8 ToRgba8()

Returns

Rgba8

The pixel.

ToRgbaF32()

Returns the color as an opaque sRGB pixel, unclamped, so colors outside sRGB keep channels outside 0..1.

public RgbaF32 ToRgbaF32()

Returns

RgbaF32

The pixel.

ToXyz()

Returns the color as XYZ (D65, white Y = 1).

public XyzColor ToXyz()

Returns

XyzColor

The color.