Colour type for the library: red, green, blue, opacity in [0,1].

Is Colour in-gamut?

>>> validColour (Colour 1 1 1.01 1)
False

Validate that the Colout is in-gamut.

>>> validate (Colour 1 1 1.01 1)
Nothing

Trim colour back to gamut.

>>> trimColour (Colour 1 1 1.01 1)
Colour 1.0 1.0 1.0 1.0

CSS-style representation

CSS-style representation

CSS-style representation

lens for opacity (or alpha channel)

Opacity or alpha

Sets RGB color but not opacity

Select a Colour from the palette

>>> palette 0
Colour 1.745945680532727e-2 0.7278003002346461 0.7974711192713982 1.0

Select a Colour from the palette with a specified opacity

>>> paletteO 0 0.5
Colour 1.745945680532727e-2 0.7278003002346461 0.7974711192713982 0.5

Zero-opacity black

>>> transparent
Colour 0.0 0.0 0.0 0.0

black

>>> black
Colour 0.0 0.0 0.0 1.0

white

>>> white
Colour 0.99 0.99 0.99 1.0

light

For lighter huds against a dark background ...

colourHudOptions light defaultHudOptions

>>> light
Colour 0.94 0.94 0.94 1.0

dark

dark is hardcoded in most of the default options.

>>> dark
Colour 5.0e-2 5.0e-2 5.0e-2 1.0

Grey(scale) colour inputting lightness and opacity.

>>> grey 0.5 0.4
Colour 0.5 0.5 0.5 0.4

LCH colour representation

oklab is a colour space being written into CSS specifications, that attempts to be ok at human-consistent colour representation. See:

• A perceptual color space for image processing
• CSS Color Module Level 5
• CSS Color Module Level 4

The type is represented by three elements:

L: Lightness ranging from 0 (LCH 0 _ _ is black) to 1 (LCH 1 _ _ is white)

C: Chromacity, which ranges from 0 to around 0.32 or so.

H: Hue, which ranges from 0 to 360

Lightness lens for LCH

Chromacity lens for LCH

Hue lens for LCH

LCHA representation, including an alpha channel.

LCHA pattern

LCH lens for LCHA

Alpha lens for LCHA

A type to represent the RGB triple, useful as an intermediary between Colour and LCHA

Lens for conversion between Double and Word8 RGB triples.

Lens for conversion between an (RGB3, alpha) pair and Colour

LAB colour representation. a is green-red and b is blue-yellow

LCHA to Colour lens

>>> c0 = Colour 0.78 0.36 0.02 1.00
>>> view (re lcha2colour') c0
LCHA' {_lch = LCH 0.5969891006896103 0.15793931531669247 49.191113810479784, _alpha = 1.0}

>>> view (re lcha2colour' % lcha2colour') c0
Colour 0.7799971480660184 0.36002701529867864 2.0019279558778965e-2 1.0

>>> c1 = Colour 0.49 0.14 0.16 1
>>> view (re lcha2colour') c1
LCHA' {_lch = LCH 0.40115567099848914 0.12279066817938503 21.51476756026837, _alpha = 1.0}

>>> view (re lcha2colour' % lcha2colour') c1
Colour 0.4899986884783269 0.14002320537292892 0.16000148010470103 1.0

Lens between generic XY color representations and CH ones, which are polar versions of the XY.

Mix 2 colours, using the oklch model.

This may not always be what you expect. One example is mixing black and another colour:

>>> mix 0.8 (Colour 0 0 0 1) (Colour 0.2 0.6 0.8 0.5)
Colour -9.09931254727234e-2 0.4761749098994677 0.448853534456995 0.6

The mix has gone out of gamut because we are swishing through hue mixes.

In this case, settting the hue on the black colour within the LCH contruct helps:

>>> betterblack = set (lch' % hLCH') (view hue' (Colour 0.2 0.6 0.8 0.5)) (review lcha2colour' black)
>>> view lcha2colour' $ mixLCHA 0.8 betterblack (review lcha2colour' $ Colour 0.2 0.6 0.8 0.5)
Colour 0.13796457900126569 0.4405742858448237 0.5918899179589158 0.6

Mix 2 colours, using the oklch model, trimming the reult back to in-gamut.

>>> mixTrim 0.8 (Colour 0 0 0 1) (Colour 0.2 0.6 0.8 0.5)
Colour 0.0 0.4761749098994677 0.448853534456995 0.6

Mix two LCHA specified colours.

Interpolate across a list of Colours, with input being in Range 0 1

>>> mixes 0 [black, (Colour 0.2 0.6 0.8 0.5), white]
Colour 0.0 0.0 0.0 1.0

>>> mixes 1 [black, (Colour 0.2 0.6 0.8 0.5), white]
Colour 0.990006487680139 0.9900235338998363 0.9900069013222627 1.0

>>> mixes 0.6 [black, (Colour 0.2 0.6 0.8 0.5), white]
Colour 0.42326087775523685 0.6697483588860055 0.8551643643270169 0.6

Convert a colour to grayscale with the same lightness.

>>> greyed (Colour 0.4 0.7 0.8 0.4)
Colour 0.6512795852495924 0.6512170310301152 0.6509875897399052 0.4

Lightness lens

>>> over lightness' (*0.8) (Colour 0.4 0.7 0.8 0.4)
Colour 0.2164521158395537 0.52366760947314 0.6192919592501553 0.4

Chromacity lens

>>> over chroma' (*0.8) (Colour 0.4 0.7 0.8 0.4)
Colour 0.4617871186277957 0.6915093453577127 0.7707963054467656 0.4

Hue lens

>>> over hue' (+180) (Colour 0.4 0.7 0.8 0.4)
Colour 0.8320015577891179 0.5836799066928026 0.48874314193645124 0.4

Html element to display colours

>>> showSwatch "swatch" dark
"<div class=swatch style=\"background:rgba(5%, 5%, 5%, 1.00);\">swatch</div>"

Show multiple colors with embedded text.

Random list of RGB3s

Random list of Colours

Random Colours with an opacity of 1 that are not too extreme in terms of lightness or chromacity.