Table of Contents

Class ColorProfile

Namespace
Egami.Colors
Assembly
Egami.dll

What a raster's numbers mean: the color model, the primaries and white point, and the transfer function. Immutable; the built-ins cover the common encodings, and Create(ColorPrimaries, TransferFunction, string?) makes any other RGB encoding.

public sealed class ColorProfile
Inheritance
ColorProfile
Inherited Members

Examples

// A ColorProfile says what a raster's numbers mean. The built-ins cover the common encodings...
ColorProfile web = ColorProfile.Srgb;
ColorProfile wide = ColorProfile.DisplayP3;
ColorProfile hdr = ColorProfile.Rec2100Pq;

// ...and Create makes any other RGB encoding from primaries and a transfer function.
ColorProfile camera = ColorProfile.Create(ColorPrimaries.AdobeRgb, TransferFunction.Gamma(2.2), "Camera RGB");
Console.WriteLine($"{camera.Name}: {camera.Model}, HDR {camera.IsHdr}, same as Adobe RGB: {camera.IsEquivalentTo(ColorProfile.AdobeRgb)}");

Properties

AdobeRgb

Gets Adobe RGB (1998): its primaries, D65, a 563/256 (about 2.2) power curve.

public static ColorProfile AdobeRgb { get; }

Property Value

ColorProfile

ChannelCount

Gets the number of channels: 3 for RGB, 1 for gray, 4 for CMYK, 2 to 15 for an n-colour profile.

public int ChannelCount { get; }

Property Value

int

ColorantNames

Gets the names of an output profile's inks, from its colorant table (clrt), in channel order; null when the profile has none.

public IReadOnlyList<string>? ColorantNames { get; }

Property Value

IReadOnlyList<string>

DisplayP3

Gets Display P3: the P3 primaries, D65, the sRGB curve, as Apple devices and CSS Color 4 use it.

public static ColorProfile DisplayP3 { get; }

Property Value

ColorProfile

Fogra39

Gets FOGRA39L: offset printing on coated paper (ISO 12647-2, paper types 1 and 2), Europe's usual press condition, built for a 300% total ink limit. The profile is colord's, built by ArgyllCMS from Fogra's measurements, as the CTAN colorprofiles package ships it (ICC version 2.2, free of known copyright restrictions); ToIcc() returns its bytes unchanged. It is read on first use. CMYK files without a profile still convert by the plain formula, not through this one.

public static ColorProfile Fogra39 { get; }

Property Value

ColorProfile

Examples

// The inks a press would use for a color, and the color it would print, through the press's CMYK profile: here the
// built-in FOGRA39 (coated offset paper); ColorProfile.FromIcc reads any other.
ColorProfile print = ColorProfile.Fogra39;
CmykColor inks = CmykColor.From(new Rgba8(200, 60, 30, 255), print, new ColorTransformOptions { Intent = RenderingIntent.RelativeColorimetric });
Rgba8 proof = inks.ToRgba8(print);

GrayLinear

Gets linear gray with D65 white.

public static ColorProfile GrayLinear { get; }

Property Value

ColorProfile

GraySrgb

Gets gray with the sRGB curve and D65 white: what a gray file without color information means.

public static ColorProfile GraySrgb { get; }

Property Value

ColorProfile

Icc

Gets the ICC profile this encoding was read from, or null.

public IccData? Icc { get; }

Property Value

IccData

IsHdr

Gets a value indicating whether the encoding is HDR (a PQ or HLG curve).

public bool IsHdr { get; }

Property Value

bool

LinearSrgb

Gets linear sRGB: BT.709 primaries, D65, no curve.

public static ColorProfile LinearSrgb { get; }

Property Value

ColorProfile

Model

Gets the color model.

public ColorModel Model { get; }

Property Value

ColorModel

Name

Gets a short name for the encoding, such as "sRGB" or the description of an ICC profile.

public string Name { get; }

Property Value

string

Primaries

Gets the primaries of an RGB encoding, or null for gray, CMYK, and ICC profiles that convert through tables rather than a matrix.

public ColorPrimaries? Primaries { get; }

Property Value

ColorPrimaries

ProPhotoRgb

Gets ProPhoto RGB (ROMM RGB): its primaries, D50, a 1.8 power with a linear segment below 1/32.

public static ColorProfile ProPhotoRgb { get; }

Property Value

ColorProfile

Rec2020

Gets Rec. 2020: BT.2020 primaries, D65, the BT.709/BT.2020 curve.

public static ColorProfile Rec2020 { get; }

Property Value

ColorProfile

Rec2100Hlg

Gets Rec. 2100 HLG: BT.2020 primaries, D65, the HLG curve (HDR).

public static ColorProfile Rec2100Hlg { get; }

Property Value

ColorProfile

Rec2100Pq

Gets Rec. 2100 PQ: BT.2020 primaries, D65, the PQ curve (HDR).

public static ColorProfile Rec2100Pq { get; }

Property Value

ColorProfile

Srgb

Gets sRGB (IEC 61966-2-1): BT.709 primaries, D65, the sRGB curve. What a file without color information means.

public static ColorProfile Srgb { get; }

Property Value

ColorProfile

Transfer

Gets the transfer function of an RGB or gray encoding, or null for CMYK, ICC profiles that convert through tables, and ICC profiles whose three curves differ.

public TransferFunction? Transfer { get; }

Property Value

TransferFunction

White

Gets the white point.

public Chromaticity White { get; }

Property Value

Chromaticity

Methods

Create(ColorPrimaries, TransferFunction, string?)

Returns an RGB encoding from primaries and a transfer function.

public static ColorProfile Create(ColorPrimaries primaries, TransferFunction transfer, string? name = null)

Parameters

primaries ColorPrimaries

The primaries, with the white point.

transfer TransferFunction

The transfer function.

name string

A name, or null for a generated one.

Returns

ColorProfile

The encoding.

Exceptions

ArgumentNullException

primaries or transfer is null.

ArgumentException

The primaries cannot form a color space (IsValid is false).

CreateGray(TransferFunction, Chromaticity?, string?)

Returns a gray encoding from a transfer function and a white point.

public static ColorProfile CreateGray(TransferFunction transfer, Chromaticity? white = null, string? name = null)

Parameters

transfer TransferFunction

The transfer function.

white Chromaticity?

The white point, or null for D65.

name string

A name, or null for a generated one.

Returns

ColorProfile

The encoding.

Exceptions

ArgumentNullException

transfer is null.

FromCodePoints(ColorCodePoints)

Returns the RGB encoding that H.273 code points name, or null when Egami does not implement the primaries or the transfer they name, or when the matrix code is not RGB (0).

public static ColorProfile? FromCodePoints(ColorCodePoints codePoints)

Parameters

codePoints ColorCodePoints

The code points.

Returns

ColorProfile

The encoding, a built-in one where it matches, or null.

FromIcc(IccData)

Returns the encoding an ICC profile describes. A matrix-shaper profile gets its primaries (un-adapted from D50 by its chad tag or its white point) and its curve, so IsEquivalentTo(ColorProfile) recognizes sRGB, Display P3 and the other built-ins written as ICC; a version 4.4 cicp tag naming a known encoding wins over the rest, as it does for HDR profiles. Profiles that convert through tables, and CMYK, keep only the model and white.

public static ColorProfile FromIcc(IccData icc)

Parameters

icc IccData

The parsed profile.

Returns

ColorProfile

The encoding, with Icc set.

Exceptions

ArgumentNullException

icc is null.

CorruptDataException

The profile is damaged where conversion needs it.

UnsupportedFormatException

The profile is not an RGB, gray or CMYK input, display, output or color space profile.

FromIcc(ReadOnlySpan<byte>)

Reads an ICC profile: FromIcc(IccData) of Parse(ReadOnlySpan<byte>, SafetyLimits?).

public static ColorProfile FromIcc(ReadOnlySpan<byte> profile)

Parameters

profile ReadOnlySpan<byte>

The profile's bytes.

Returns

ColorProfile

The encoding.

Exceptions

CorruptDataException

The profile is damaged where conversion needs it.

UnsupportedFormatException

The profile is not an RGB, gray or CMYK input, display, output or color space profile.

IsEquivalentTo(ColorProfile)

Returns whether two encodings mean the same colors: the same model, primaries and white within 1e-4, and curves that agree within 1e-4 (so an ICC profile written for sRGB is equivalent to Srgb).

public bool IsEquivalentTo(ColorProfile other)

Parameters

other ColorProfile

The other encoding.

Returns

bool

true if they are equivalent.

ToCodePoints()

Returns the H.273 code points of this encoding, or null when its primaries or curve have none (Adobe RGB, ProPhoto, gray, CMYK, parametric and sampled curves).

public ColorCodePoints? ToCodePoints()

Returns

ColorCodePoints?

The code points, or null.

ToIcc()

Returns an ICC profile for this encoding: the bytes it was read from, or a small version 4 profile written for it (4.3 with parametric curves for SDR encodings, 4.4 with a cicp tag for PQ and HLG), which Little CMS, browsers and image tools read.

public byte[] ToIcc()

Returns

byte[]

A new array holding the profile.

Examples

// Any RGB or gray encoding as a small ICC profile, for files and other software.
byte[] p3 = ColorProfile.DisplayP3.ToIcc();
bool same = ColorProfile.FromIcc(p3).IsEquivalentTo(ColorProfile.DisplayP3);

ToIccV2()

Returns a version 2 ICC profile for this encoding, for readers that do not read version 4 ones (older image editors, viewers and print drivers): the bytes it was read from when they are a version 2 profile, else a small version 2.4 matrix-shaper (or gray curve) profile written for it, with curv curves (a gamma or a 1024-entry table) and its own white as the media white point. PQ and HLG get the rolled-off tables ToIcc() writes, without the cicp tag version 2 lacks.

public byte[] ToIccV2()

Returns

byte[]

A new array holding the profile.

Examples

// A version 2 profile, for software that reads only those: older image editors, viewers and print drivers.
byte[] p3 = ColorProfile.DisplayP3.ToIccV2();
Version version = IccData.Parse(p3).Version;

Exceptions

InvalidOperationException

The encoding is not RGB or gray with one curve, which a version 2 matrix-shaper cannot hold.

ToString()

Returns a string that represents the current object.

public override string ToString()

Returns

string

A string that represents the current object.

Edit this page