Data.Colour.RGBSpace

An RGBSpace is characterized by Chromaticity for red, green, and blue, the Chromaticity of the white point, and it's TransferFunction.

Documentation

data Colour a

This type represents the human preception of colour. The a parameter is a numeric type used internally for the representation.

The Monoid instance allows one to add colours, but beware that adding colours can take you out of gamut. Consider using blend whenever possible.

Instances

ColourOps Colour

AffineSpace Colour

Eq a => Eq (Colour a)

(Fractional a, Read a) => Read (Colour a)

(Fractional a, Show a) => Show (Colour a)

Num a => Monoid (Colour a)

RGB Tuple

data RGB a

An RGB triple for an unspecified colour space.

Constructors

RGB

Fields

channelRed :: !a

channelGreen :: !a

channelBlue :: !a

Instances

Functor RGB

Applicative RGB

Eq a => Eq (RGB a)

Read a => Read (RGB a)

Show a => Show (RGB a)

uncurryRGB :: (a -> a -> a -> b) -> RGB a -> b

Uncurries a function expecting three r, g, b parameters.

curryRGB :: (RGB a -> b) -> a -> a -> a -> b

Curries a function expecting one RGB parameter.

RGB Gamut

data RGBGamut

An RGBGamut is a 3-D colour “cube” that contains all the colours that can be displayed by a RGB device. The “cube” is normalized so that white has Data.Colour.CIE.luminance 1.

Instances

Eq RGBGamut

Read RGBGamut

Show RGBGamut

mkRGBGamut

Arguments

:: RGB (Chromaticity Rational)

The three primaries

-> Chromaticity Rational

The white point

-> RGBGamut

An RGB gamut is specified by three primary colours (red, green, and blue) and a white point (often Data.Colour.CIE.Illuminant.d65).

primaries :: RGBGamut -> RGB (Chromaticity Rational)

whitePoint :: RGBGamut -> Chromaticity Rational

inGamut :: (Ord a, Fractional a) => RGBGamut -> Colour a -> Bool

Returns True if the given colour lies inside the given gamut.

RGB Space

data TransferFunction a

A transfer function is a function that typically translates linear colour space coordinates into non-linear coordinates. The transferInverse function reverses this by translating non-linear colour space coordinates into linear coordinates. It is required that

 transfer . transferInverse === id === transferInverse . inverse

(or that this law holds up to floating point rounding errors).

We also require that transfer is approximately (**transferGamma) (and hence transferInverse is approximately (**(recip transferGamma))). The value transferGamma is for informational purposes only, so there is no bound on how good this approximation needs to be.

Constructors

TransferFunction

Fields

transfer :: a -> a

transferInverse :: a -> a

transferGamma :: a

Instances

Num a => Monoid (TransferFunction a)

linearTransferFunction :: Num a => TransferFunction a

This is the identity TransferFunction.

powerTransferFunction :: Floating a => a -> TransferFunction a

This is the (**gamma) TransferFunction.

inverseTransferFunction :: Fractional a => TransferFunction a -> TransferFunction a

This reverses a TransferFunction.

data RGBSpace a

An RGBSpace is a colour coordinate system for colours laying inGamut of gamut. Linear coordinates are passed through a transferFunction to produce non-linear RGB values.

mkRGBSpace :: RGBGamut -> TransferFunction a -> RGBSpace a

An RGBSpace is specified by an RGBGamut and a TransferFunction.

gamut :: RGBSpace a -> RGBGamut

transferFunction :: RGBSpace a -> TransferFunction a

linearRGBSpace :: Num a => RGBGamut -> RGBSpace a

Produce a linear colour space from an RGBGamut.

rgbUsingSpace :: Fractional a => RGBSpace a -> a -> a -> a -> Colour a

Create a Colour from red, green, and blue coordinates given in a general RGBSpace.

toRGBUsingSpace :: Fractional a => RGBSpace a -> Colour a -> RGB a

Return the coordinates of a given Colour for a general RGBSpace.