Data.Colour.Internal

Documentation

data Red

Constructors

Red

data Green

Constructors

Green

data Blue

Constructors

Blue

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.

Constructors

RGB !(Chan Red a) !(Chan Green a) !(Chan Blue a)

Instances

ColourOps Colour

Methods

over :: Num a => AlphaColour a -> Colour a -> Colour a

darken :: Num a => a -> Colour a -> Colour a

AffineSpace Colour

Methods

affineCombo :: Num a => [(a, Colour a)] -> Colour a -> Colour a

Eq a => Eq (Colour a)

Methods

(==) :: Colour a -> Colour a -> Bool

(/=) :: Colour a -> Colour a -> Bool

Num a => Semigroup (Colour a)

Methods

(<>) :: Colour a -> Colour a -> Colour a

sconcat :: NonEmpty (Colour a) -> Colour a

stimes :: Integral b => b -> Colour a -> Colour a

Num a => Monoid (Colour a)

Methods

mempty :: Colour a

mappend :: Colour a -> Colour a -> Colour a

mconcat :: [Colour a] -> Colour a

colourConvert :: (Fractional b, Real a) => Colour a -> Colour b

Change the type used to represent the colour coordinates.

black :: Num a => Colour a

data Alpha

Constructors

Alpha

data AlphaColour a

This type represents a Colour that may be semi-transparent.

The Monoid instance allows you to composite colours.

x `mappend` y == x `over` y

To get the (pre-multiplied) colour channel of an AlphaColour c, simply composite c over black.

c `over` black

Constructors

RGBA !(Colour a) !(Chan Alpha a)

Instances

ColourOps AlphaColour

Methods

over :: Num a => AlphaColour a -> AlphaColour a -> AlphaColour a

darken :: Num a => a -> AlphaColour a -> AlphaColour a

AffineSpace AlphaColour

Methods

affineCombo :: Num a => [(a, AlphaColour a)] -> AlphaColour a -> AlphaColour a

Eq a => Eq (AlphaColour a)

Methods

(==) :: AlphaColour a -> AlphaColour a -> Bool

(/=) :: AlphaColour a -> AlphaColour a -> Bool

Num a => Semigroup (AlphaColour a)

AlphaColour forms a monoid with over and transparent.

Methods

(<>) :: AlphaColour a -> AlphaColour a -> AlphaColour a

sconcat :: NonEmpty (AlphaColour a) -> AlphaColour a

stimes :: Integral b => b -> AlphaColour a -> AlphaColour a

Num a => Monoid (AlphaColour a)

Methods

mempty :: AlphaColour a

mappend :: AlphaColour a -> AlphaColour a -> AlphaColour a

mconcat :: [AlphaColour a] -> AlphaColour a

transparent :: Num a => AlphaColour a

This AlphaColour is entirely transparent and has no associated colour channel.

alphaColourConvert :: (Fractional b, Real a) => AlphaColour a -> AlphaColour b

Change the type used to represent the colour coordinates.

opaque :: Num a => Colour a -> AlphaColour a

Creates an opaque AlphaColour from a Colour.

dissolve :: Num a => a -> AlphaColour a -> AlphaColour a

Returns an AlphaColour more transparent by a factor of o.

withOpacity :: Num a => Colour a -> a -> AlphaColour a

Creates an AlphaColour from a Colour with a given opacity.

c `withOpacity` o == dissolve o (opaque c) 

class AffineSpace f where

Minimal complete definition

affineCombo

Methods

affineCombo :: Num a => [(a, f a)] -> f a -> f a

Compute a affine Combination (weighted-average) of points. The last parameter will get the remaining weight. e.g.

affineCombo [(0.2,a), (0.3,b)] c == 0.2*a + 0.3*b + 0.5*c

Weights can be negative, or greater than 1.0; however, be aware that non-convex combinations may lead to out of gamut colours.

Instances

AffineSpace AlphaColour

Methods

affineCombo :: Num a => [(a, AlphaColour a)] -> AlphaColour a -> AlphaColour a

AffineSpace Colour

Methods

affineCombo :: Num a => [(a, Colour a)] -> Colour a -> Colour a

blend :: (Num a, AffineSpace f) => a -> f a -> f a -> f a

Compute the weighted average of two points. e.g.

blend 0.4 a b = 0.4*a + 0.6*b

The weight can be negative, or greater than 1.0; however, be aware that non-convex combinations may lead to out of gamut colours.

class ColourOps f where

Minimal complete definition

over, darken

Methods

over :: Num a => AlphaColour a -> f a -> f a

c1 `over` c2 returns the Colour created by compositing the AlphaColour c1 over c2, which may be either a Colour or AlphaColour.

darken :: Num a => a -> f a -> f a

darken s c blends a colour with black without changing it's opacity.

For Colour, darken s c = blend s c mempty

Instances

ColourOps AlphaColour

Methods

over :: Num a => AlphaColour a -> AlphaColour a -> AlphaColour a

darken :: Num a => a -> AlphaColour a -> AlphaColour a

ColourOps Colour

Methods

over :: Num a => AlphaColour a -> Colour a -> Colour a

darken :: Num a => a -> Colour a -> Colour a

atop :: Fractional a => AlphaColour a -> AlphaColour a -> AlphaColour a

c1 `atop` c2 returns the AlphaColour produced by covering the portion of c2 visible by c1. The resulting alpha channel is always the same as the alpha channel of c2.

c1 `atop` (opaque c2) == c1 `over` (opaque c2)
AlphaChannel (c1 `atop` c2) == AlphaChannel c2

quantize :: (RealFrac a1, Integral a, Bounded a) => a1 -> a

rounds and then clamps x between 0 and maxBound.

alphaChannel :: AlphaColour a -> a

Returns the opacity of an AlphaColour.

colourChannel :: Fractional a => AlphaColour a -> Colour a

Returns the colour of an AlphaColour. colourChannel transparent is undefined and may result in nan or an error. Its use is discouraged. If you are desperate, use

darken (recip (alphaChannel c)) (c `over` black)

rgbaAdd :: Num a => AlphaColour a -> AlphaColour a -> AlphaColour a