-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | A model for human colour/color perception
--   
--   This package provides a data type for colours and transparency.
--   Colours can be blended and composed. Various colour spaces are
--   supported. A module of colour names (<a>Data.Colour.Names</a>) is
--   provided.
@package colour
@version 2.2.0

module Data.Colour.RGBSpace.HSL

-- | An RGB triple for an unspecified colour space.
data RGB a

-- | Returns the HSL (hue-saturation-lightness) coordinates of an
--   <a>RGB</a> triple. See <a>hue</a>, <a>saturation</a>, and
--   <a>lightness</a>.
hslView :: (Fractional a, Ord a) => RGB a -> (a, a, a)

-- | The <a>hue</a> coordinate of an <a>RGB</a> value is in degrees. Its
--   value is always in the range 0-360.
hue :: (Fractional a, Ord a) => RGB a -> a

-- | Returns the saturation coordinate of an <a>RGB</a> triple for the HSL
--   (hue-saturation-lightness) system. Note: This is different from
--   <tt>Data.Colour.RGBSpace.HSV.saturation</tt> for the
--   <a>Data.Colour.RGBSpace.HSV</a>
saturation :: (Fractional a, Ord a) => RGB a -> a

-- | Returns the lightness coordinate of an <a>RGB</a> triple for the HSL
--   (hue-saturation-lightness) system.
lightness :: (Fractional a, Ord a) => RGB a -> a

-- | Convert HSL (hue-saturation-lightness) coordinates to an <a>RGB</a>
--   value. Hue is expected to be measured in degrees.
hsl :: (RealFrac a, Ord a) => a -> a -> a -> RGB a

module Data.Colour.RGBSpace.HSV

-- | An RGB triple for an unspecified colour space.
data RGB a

-- | Returns the HSV (hue-saturation-value) coordinates of an <a>RGB</a>
--   triple. See <a>hue</a>, <a>saturation</a>, and <a>value</a>.
hsvView :: (Fractional a, Ord a) => RGB a -> (a, a, a)

-- | The <a>hue</a> coordinate of an <a>RGB</a> value is in degrees. Its
--   value is always in the range 0-360.
hue :: (Fractional a, Ord a) => RGB a -> a

-- | Returns the saturation coordinate of an <a>RGB</a> triple for the HSV
--   (hue-saturation-value) system. Note: This is different from
--   <tt>Data.Colour.RGBSpace.HSL.saturation</tt> for the
--   <a>Data.Colour.RGBSpace.HSL</a>
saturation :: (Fractional a, Ord a) => RGB a -> a

-- | Returns the value coordinate of an <a>RGB</a> triple for the HSV
--   (hue-saturation-value) system.
value :: (Fractional a, Ord a) => RGB a -> a

-- | Convert HSV (hue-saturation-value) coordinates to an <a>RGB</a> value.
--   Hue is expected to be measured in degrees.
hsv :: (RealFrac a, Ord a) => a -> a -> a -> RGB a


-- | Standard illuminants defined by the International Commission on
--   Illumination (CIE).
module Data.Colour.CIE.Illuminant

-- | Incandescent / Tungsten
a :: (Fractional a) => Chromaticity a

-- | {obsolete} Direct sunlight at noon
b :: (Fractional a) => Chromaticity a

-- | {obsolete} Average / North sky Daylight
c :: (Fractional a) => Chromaticity a

-- | Horizon Light. ICC profile PCS
d50 :: (Fractional a) => Chromaticity a

-- | Mid-morning / Mid-afternoon Daylight
d55 :: (Fractional a) => Chromaticity a

-- | Noon Daylight: Television, sRGB color space
d65 :: (Fractional a) => Chromaticity a

-- | North sky Daylight
d75 :: (Fractional a) => Chromaticity a

-- | Equal energy
e :: (Fractional a) => Chromaticity a

-- | Daylight Fluorescent
f1 :: (Fractional a) => Chromaticity a

-- | Cool White Fluorescent
f2 :: (Fractional a) => Chromaticity a

-- | White Fluorescent
f3 :: (Fractional a) => Chromaticity a

-- | Warm White Fluorescent
f4 :: (Fractional a) => Chromaticity a

-- | Daylight Fluorescent
f5 :: (Fractional a) => Chromaticity a

-- | Lite White Fluorescent
f6 :: (Fractional a) => Chromaticity a

-- | D65 simulator, Daylight simulator
f7 :: (Fractional a) => Chromaticity a

-- | D50 simulator, Sylvania F40 Design 50
f8 :: (Fractional a) => Chromaticity a

-- | Cool White Deluxe Fluorescent
f9 :: (Fractional a) => Chromaticity a

-- | Philips TL85, Ultralume 50
f10 :: (Fractional a) => Chromaticity a

-- | Philips TL84, Ultralume 40
f11 :: (Fractional a) => Chromaticity a

-- | Philips TL83, Ultralume 30
f12 :: (Fractional a) => Chromaticity a


-- | Provides a <i>linear</i> colour space with the same gamut as
--   <a>Data.Colour.SRGB</a>.
module Data.Colour.SRGB.Linear

-- | This type represents the human preception of colour. The <tt>a</tt>
--   parameter is a numeric type used internally for the representation.
--   
--   The <a>Monoid</a> instance allows one to add colours, but beware that
--   adding colours can take you out of gamut. Consider using <a>blend</a>
--   whenever possible.
data Colour a

-- | An RGB triple for an unspecified colour space.
data RGB a
RGB :: !a -> !a -> !a -> RGB a
channelRed :: RGB a -> !a
channelGreen :: RGB a -> !a
channelBlue :: RGB a -> !a

-- | Constructs a <a>Colour</a> from RGB values using the <i>linear</i> RGB
--   colour with the same gamut as sRGB.
rgb :: (Fractional a) => a -> a -> a -> Colour a

-- | Return RGB values using the <i>linear</i> RGB colour with the same
--   gamut as sRGB.
toRGB :: (Fractional a) => Colour a -> RGB a

-- | This is the gamut for the sRGB colour space.
sRGBGamut :: RGBGamut


-- | An <a>RGBSpace</a> is characterized by <a>Chromaticity</a> for red,
--   green, and blue, the <a>Chromaticity</a> of the white point, and it's
--   <a>TransferFunction</a>.
module Data.Colour.RGBSpace

-- | This type represents the human preception of colour. The <tt>a</tt>
--   parameter is a numeric type used internally for the representation.
--   
--   The <a>Monoid</a> instance allows one to add colours, but beware that
--   adding colours can take you out of gamut. Consider using <a>blend</a>
--   whenever possible.
data Colour a

-- | An RGB triple for an unspecified colour space.
data RGB a
RGB :: !a -> !a -> !a -> RGB a
channelRed :: RGB a -> !a
channelGreen :: RGB a -> !a
channelBlue :: RGB a -> !a

-- | Uncurries a function expecting three r, g, b parameters.
uncurryRGB :: (a -> a -> a -> b) -> RGB a -> b

-- | Curries a function expecting one RGB parameter.
curryRGB :: (RGB a -> b) -> a -> a -> a -> b

-- | An <a>RGBGamut</a> 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 <tt>Data.Colour.CIE.luminance</tt> 1.
data RGBGamut

-- | An RGB gamut is specified by three primary colours (red, green, and
--   blue) and a white point (often
--   <tt>Data.Colour.CIE.Illuminant.d65</tt>).
mkRGBGamut :: RGB (Chromaticity Rational) -> Chromaticity Rational -> RGBGamut
primaries :: RGBGamut -> (RGB (Chromaticity Rational))
whitePoint :: RGBGamut -> (Chromaticity Rational)

-- | Returns <a>True</a> if the given colour lies inside the given gamut.
inGamut :: (Ord a, Fractional a) => RGBGamut -> Colour a -> Bool

-- | A <a>transfer</a> function is a function that typically translates
--   linear colour space coordinates into non-linear coordinates. The
--   <a>transferInverse</a> function reverses this by translating
--   non-linear colour space coordinates into linear coordinates. It is
--   required that
--   
--   <pre>
--   transfer . transferInverse === id === transferInverse . inverse
--   </pre>
--   
--   (or that this law holds up to floating point rounding errors).
--   
--   We also require that <a>transfer</a> is approximately
--   <tt>(**transferGamma)</tt> (and hence <a>transferInverse</a> is
--   approximately <tt>(**(recip transferGamma))</tt>). The value
--   <a>transferGamma</a> is for informational purposes only, so there is
--   no bound on how good this approximation needs to be.
data TransferFunction a
TransferFunction :: (a -> a) -> (a -> a) -> a -> TransferFunction a
transfer :: TransferFunction a -> a -> a
transferInverse :: TransferFunction a -> a -> a
transferGamma :: TransferFunction a -> a

-- | This is the identity <a>TransferFunction</a>.
linearTransferFunction :: (Num a) => TransferFunction a

-- | This is the <tt>(**gamma)</tt> <a>TransferFunction</a>.
powerTransferFunction :: (Floating a) => a -> TransferFunction a

-- | This reverses a <a>TransferFunction</a>.
inverseTransferFunction :: (Fractional a) => TransferFunction a -> TransferFunction a

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

-- | An RGBSpace is specified by an <a>RGBGamut</a> and a
--   <a>TransferFunction</a>.
mkRGBSpace :: RGBGamut -> TransferFunction a -> RGBSpace a
gamut :: RGBSpace a -> RGBGamut
transferFunction :: RGBSpace a -> TransferFunction a

-- | Produce a linear colour space from an <a>RGBGamut</a>.
linearRGBSpace :: (Num a) => RGBGamut -> RGBSpace a

-- | Create a <a>Colour</a> from red, green, and blue coordinates given in
--   a general <a>RGBSpace</a>.
rgbUsingSpace :: (Fractional a) => RGBSpace a -> a -> a -> a -> Colour a

-- | Return the coordinates of a given <a>Colour</a> for a general
--   <a>RGBSpace</a>.
toRGBUsingSpace :: (Fractional a) => RGBSpace a -> Colour a -> RGB a
instance (Num a) => Monoid (TransferFunction a)


-- | Specifies <a>Colour</a>s in accordance with the sRGB standard.
module Data.Colour.SRGB

-- | This type represents the human preception of colour. The <tt>a</tt>
--   parameter is a numeric type used internally for the representation.
--   
--   The <a>Monoid</a> instance allows one to add colours, but beware that
--   adding colours can take you out of gamut. Consider using <a>blend</a>
--   whenever possible.
data Colour a

-- | An RGB triple for an unspecified colour space.
data RGB a
RGB :: !a -> !a -> !a -> RGB a
channelRed :: RGB a -> !a
channelGreen :: RGB a -> !a
channelBlue :: RGB a -> !a

-- | Construct a colour from a 24-bit (three 8-bit words) sRGB
--   specification.
sRGB24 :: (Ord b, Floating b) => Word8 -> Word8 -> Word8 -> Colour b

-- | Construct a colour from an sRGB specification. Input components are
--   expected to be in the range [0..<a>maxBound</a>].
sRGBBounded :: (Ord b, Floating b, Integral a, Bounded a) => a -> a -> a -> Colour b

-- | Construct a colour from an sRGB specification. Input components are
--   expected to be in the range [0..1].
sRGB :: (Ord b, Floating b) => b -> b -> b -> Colour b

-- | Return the approximate 24-bit sRGB colour components as three 8-bit
--   components. Out of range values are clamped.
toSRGB24 :: (RealFrac b, Floating b) => Colour b -> RGB Word8

-- | Return the approximate sRGB colour components in the range
--   [0..<a>maxBound</a>]. Out of range values are clamped.
toSRGBBounded :: (RealFrac b, Floating b, Integral a, Bounded a) => Colour b -> RGB a

-- | Return the sRGB colour components in the range [0..1].
toSRGB :: (Ord b, Floating b) => Colour b -> RGB b

-- | Show a colour in hexadecimal form, e.g. "#00aaff"
sRGB24shows :: (RealFrac b, Floating b) => Colour b -> ShowS

-- | Show a colour in hexadecimal form, e.g. "#00aaff"
sRGB24show :: (RealFrac b, Floating b) => Colour b -> String

-- | Read a colour in hexadecimal form, e.g. "#00aaff" or "00aaff"
sRGB24reads :: (Ord b, Floating b) => ReadS (Colour b)

-- | Read a colour in hexadecimal form, e.g. "#00aaff" or "00aaff"
sRGB24read :: (Ord b, Floating b) => String -> (Colour b)

-- | The sRGB colour space
sRGBSpace :: (Ord a, Floating a) => RGBSpace a


-- | Names for colours. Names taken from SVG 1.1 specification,
--   <a>http://www.w3.org/TR/SVG11/types.html#ColorKeywords</a>.
--   
--   <a>readColourName</a> takes a string naming a colour (must be all
--   lowercase) and returns the colour. Fails if the name is not
--   recognized.
module Data.Colour.Names
readColourName :: (Monad m, Ord a, Floating a) => String -> m (Colour a)
aliceblue :: (Ord a, Floating a) => Colour a
antiquewhite :: (Ord a, Floating a) => Colour a
aqua :: (Ord a, Floating a) => Colour a
aquamarine :: (Ord a, Floating a) => Colour a
azure :: (Ord a, Floating a) => Colour a
beige :: (Ord a, Floating a) => Colour a
bisque :: (Ord a, Floating a) => Colour a
black :: (Ord a, Floating a) => Colour a
blanchedalmond :: (Ord a, Floating a) => Colour a
blue :: (Ord a, Floating a) => Colour a
blueviolet :: (Ord a, Floating a) => Colour a
brown :: (Ord a, Floating a) => Colour a
burlywood :: (Ord a, Floating a) => Colour a
cadetblue :: (Ord a, Floating a) => Colour a
chartreuse :: (Ord a, Floating a) => Colour a
chocolate :: (Ord a, Floating a) => Colour a
coral :: (Ord a, Floating a) => Colour a
cornflowerblue :: (Ord a, Floating a) => Colour a
cornsilk :: (Ord a, Floating a) => Colour a
crimson :: (Ord a, Floating a) => Colour a
cyan :: (Ord a, Floating a) => Colour a
darkblue :: (Ord a, Floating a) => Colour a
darkcyan :: (Ord a, Floating a) => Colour a
darkgoldenrod :: (Ord a, Floating a) => Colour a
darkgray :: (Ord a, Floating a) => Colour a
darkgreen :: (Ord a, Floating a) => Colour a
darkgrey :: (Ord a, Floating a) => Colour a
darkkhaki :: (Ord a, Floating a) => Colour a
darkmagenta :: (Ord a, Floating a) => Colour a
darkolivegreen :: (Ord a, Floating a) => Colour a
darkorange :: (Ord a, Floating a) => Colour a
darkorchid :: (Ord a, Floating a) => Colour a
darkred :: (Ord a, Floating a) => Colour a
darksalmon :: (Ord a, Floating a) => Colour a
darkseagreen :: (Ord a, Floating a) => Colour a
darkslateblue :: (Ord a, Floating a) => Colour a
darkslategray :: (Ord a, Floating a) => Colour a
darkslategrey :: (Ord a, Floating a) => Colour a
darkturquoise :: (Ord a, Floating a) => Colour a
darkviolet :: (Ord a, Floating a) => Colour a
deeppink :: (Ord a, Floating a) => Colour a
deepskyblue :: (Ord a, Floating a) => Colour a
dimgray :: (Ord a, Floating a) => Colour a
dimgrey :: (Ord a, Floating a) => Colour a
dodgerblue :: (Ord a, Floating a) => Colour a
firebrick :: (Ord a, Floating a) => Colour a
floralwhite :: (Ord a, Floating a) => Colour a
forestgreen :: (Ord a, Floating a) => Colour a
fuchsia :: (Ord a, Floating a) => Colour a
gainsboro :: (Ord a, Floating a) => Colour a
ghostwhite :: (Ord a, Floating a) => Colour a
gold :: (Ord a, Floating a) => Colour a
goldenrod :: (Ord a, Floating a) => Colour a
gray :: (Ord a, Floating a) => Colour a
grey :: (Ord a, Floating a) => Colour a
green :: (Ord a, Floating a) => Colour a
greenyellow :: (Ord a, Floating a) => Colour a
honeydew :: (Ord a, Floating a) => Colour a
hotpink :: (Ord a, Floating a) => Colour a
indianred :: (Ord a, Floating a) => Colour a
indigo :: (Ord a, Floating a) => Colour a
ivory :: (Ord a, Floating a) => Colour a
khaki :: (Ord a, Floating a) => Colour a
lavender :: (Ord a, Floating a) => Colour a
lavenderblush :: (Ord a, Floating a) => Colour a
lawngreen :: (Ord a, Floating a) => Colour a
lemonchiffon :: (Ord a, Floating a) => Colour a
lightblue :: (Ord a, Floating a) => Colour a
lightcoral :: (Ord a, Floating a) => Colour a
lightcyan :: (Ord a, Floating a) => Colour a
lightgoldenrodyellow :: (Ord a, Floating a) => Colour a
lightgray :: (Ord a, Floating a) => Colour a
lightgreen :: (Ord a, Floating a) => Colour a
lightgrey :: (Ord a, Floating a) => Colour a
lightpink :: (Ord a, Floating a) => Colour a
lightsalmon :: (Ord a, Floating a) => Colour a
lightseagreen :: (Ord a, Floating a) => Colour a
lightskyblue :: (Ord a, Floating a) => Colour a
lightslategray :: (Ord a, Floating a) => Colour a
lightslategrey :: (Ord a, Floating a) => Colour a
lightsteelblue :: (Ord a, Floating a) => Colour a
lightyellow :: (Ord a, Floating a) => Colour a
lime :: (Ord a, Floating a) => Colour a
limegreen :: (Ord a, Floating a) => Colour a
linen :: (Ord a, Floating a) => Colour a
magenta :: (Ord a, Floating a) => Colour a
maroon :: (Ord a, Floating a) => Colour a
mediumaquamarine :: (Ord a, Floating a) => Colour a
mediumblue :: (Ord a, Floating a) => Colour a
mediumorchid :: (Ord a, Floating a) => Colour a
mediumpurple :: (Ord a, Floating a) => Colour a
mediumseagreen :: (Ord a, Floating a) => Colour a
mediumslateblue :: (Ord a, Floating a) => Colour a
mediumspringgreen :: (Ord a, Floating a) => Colour a
mediumturquoise :: (Ord a, Floating a) => Colour a
mediumvioletred :: (Ord a, Floating a) => Colour a
midnightblue :: (Ord a, Floating a) => Colour a
mintcream :: (Ord a, Floating a) => Colour a
mistyrose :: (Ord a, Floating a) => Colour a
moccasin :: (Ord a, Floating a) => Colour a
navajowhite :: (Ord a, Floating a) => Colour a
navy :: (Ord a, Floating a) => Colour a
oldlace :: (Ord a, Floating a) => Colour a
olive :: (Ord a, Floating a) => Colour a
olivedrab :: (Ord a, Floating a) => Colour a
orange :: (Ord a, Floating a) => Colour a
orangered :: (Ord a, Floating a) => Colour a
orchid :: (Ord a, Floating a) => Colour a
palegoldenrod :: (Ord a, Floating a) => Colour a
palegreen :: (Ord a, Floating a) => Colour a
paleturquoise :: (Ord a, Floating a) => Colour a
palevioletred :: (Ord a, Floating a) => Colour a
papayawhip :: (Ord a, Floating a) => Colour a
peachpuff :: (Ord a, Floating a) => Colour a
peru :: (Ord a, Floating a) => Colour a
pink :: (Ord a, Floating a) => Colour a
plum :: (Ord a, Floating a) => Colour a
powderblue :: (Ord a, Floating a) => Colour a
purple :: (Ord a, Floating a) => Colour a
red :: (Ord a, Floating a) => Colour a
rosybrown :: (Ord a, Floating a) => Colour a
royalblue :: (Ord a, Floating a) => Colour a
saddlebrown :: (Ord a, Floating a) => Colour a
salmon :: (Ord a, Floating a) => Colour a
sandybrown :: (Ord a, Floating a) => Colour a
seagreen :: (Ord a, Floating a) => Colour a
seashell :: (Ord a, Floating a) => Colour a
sienna :: (Ord a, Floating a) => Colour a
silver :: (Ord a, Floating a) => Colour a
skyblue :: (Ord a, Floating a) => Colour a
slateblue :: (Ord a, Floating a) => Colour a
slategray :: (Ord a, Floating a) => Colour a
slategrey :: (Ord a, Floating a) => Colour a
snow :: (Ord a, Floating a) => Colour a
springgreen :: (Ord a, Floating a) => Colour a
steelblue :: (Ord a, Floating a) => Colour a
tan :: (Ord a, Floating a) => Colour a
teal :: (Ord a, Floating a) => Colour a
thistle :: (Ord a, Floating a) => Colour a
tomato :: (Ord a, Floating a) => Colour a
turquoise :: (Ord a, Floating a) => Colour a
violet :: (Ord a, Floating a) => Colour a
wheat :: (Ord a, Floating a) => Colour a
white :: (Ord a, Floating a) => Colour a
whitesmoke :: (Ord a, Floating a) => Colour a
yellow :: (Ord a, Floating a) => Colour a
yellowgreen :: (Ord a, Floating a) => Colour a


-- | Datatypes for representing the human perception of colour. Includes
--   common operations for blending and compositing colours. The most
--   common way of creating colours is either by name (see
--   <a>Data.Colour.Names</a>) or by giving an sRGB triple (see
--   <a>Data.Colour.SRGB</a>).
--   
--   Methods of specifying Colours can be found in
--   
--   <ul>
--   <li><a>Data.Colour.SRGB</a></li>
--   <li><a>Data.Colour.SRGB.Linear</a></li>
--   <li><a>Data.Colour.CIE</a></li>
--   </ul>
--   
--   Colours can be specified in a generic
--   <tt>Data.Colour.RGBSpace.RGBSpace</tt> by using
--   
--   <ul>
--   <li><a>Data.Colour.RGBSpace</a></li>
--   </ul>
module Data.Colour

-- | This type represents the human preception of colour. The <tt>a</tt>
--   parameter is a numeric type used internally for the representation.
--   
--   The <a>Monoid</a> instance allows one to add colours, but beware that
--   adding colours can take you out of gamut. Consider using <a>blend</a>
--   whenever possible.
data Colour a

-- | Change the type used to represent the colour coordinates.
colourConvert :: (Fractional b, Real a) => Colour a -> Colour b

-- | This type represents a <a>Colour</a> that may be semi-transparent.
--   
--   The <a>Monoid</a> instance allows you to composite colours.
--   
--   <pre>
--   x `mappend` y == x `over` y
--   </pre>
--   
--   To get the (pre-multiplied) colour channel of an <a>AlphaColour</a>
--   <tt>c</tt>, simply composite <tt>c</tt> over black.
--   
--   <pre>
--   c `over` (mempty :: Colour a)
--   </pre>
data AlphaColour a

-- | Creates an opaque <a>AlphaColour</a> from a <a>Colour</a>.
opaque :: (Num a) => Colour a -> AlphaColour a

-- | Creates an <a>AlphaColour</a> from a <a>Colour</a> with a given
--   opacity.
--   
--   <pre>
--   c `withOpacity` o == dissolve o (opaque c) 
--   </pre>
withOpacity :: (Num a) => Colour a -> a -> AlphaColour a

-- | This <a>AlphaColour</a> is entirely transparent and has no associated
--   colour channel.
transparent :: (Num a) => AlphaColour a

-- | Change the type used to represent the colour coordinates.
alphaColourConvert :: (Fractional b, Real a) => AlphaColour a -> AlphaColour b

-- | Returns the opacity of an <a>AlphaColour</a>.
alphaChannel :: AlphaColour a -> a
class AffineSpace f
affineCombo :: (AffineSpace f, Num a) => [(a, f a)] -> f a -> f a

-- | Compute the weighted average of two points. e.g.
--   
--   <pre>
--   blend 0.4 a b = 0.4*a + 0.6*b
--   </pre>
--   
--   The weight can be negative, or greater than 1.0; however, be aware
--   that non-convex combinations may lead to out of gamut colours.
blend :: (Num a, AffineSpace f) => a -> f a -> f a -> f a
class ColourOps f
over :: (ColourOps f, Num a) => AlphaColour a -> f a -> f a
darken :: (ColourOps f, Num a) => a -> f a -> f a

-- | Returns an <a>AlphaColour</a> more transparent by a factor of
--   <tt>o</tt>.
dissolve :: (Num a) => a -> AlphaColour a -> AlphaColour a

-- | <tt>c1 `atop` c2</tt> returns the <a>AlphaColour</a> produced by
--   covering the portion of <tt>c2</tt> visible by <tt>c1</tt>. The
--   resulting alpha channel is always the same as the alpha channel of
--   <tt>c2</tt>.
--   
--   <pre>
--   c1 `atop` (opaque c2) == c1 `over` (opaque c2)
--   AlphaChannel (c1 `atop` c2) == AlphaChannel c2
--   </pre>
atop :: (Fractional a) => AlphaColour a -> AlphaColour a -> AlphaColour a
instance (Fractional a, Read a) => Read (AlphaColour a)
instance (Fractional a) => Show (AlphaColour a)
instance (Fractional a, Read a) => Read (Colour a)
instance (Fractional a) => Show (Colour a)


-- | Colour operations defined by the International Commission on
--   Illumination (CIE).
module Data.Colour.CIE

-- | This type represents the human preception of colour. The <tt>a</tt>
--   parameter is a numeric type used internally for the representation.
--   
--   The <a>Monoid</a> instance allows one to add colours, but beware that
--   adding colours can take you out of gamut. Consider using <a>blend</a>
--   whenever possible.
data Colour a

-- | Construct a <a>Colour</a> from XYZ coordinates for the 2° standard
--   (colourimetric) observer.
cieXYZ :: (Fractional a) => a -> a -> a -> Colour a

-- | Return the XYZ colour coordinates for the 2° standard (colourimetric)
--   observer.
toCIEXYZ :: (Fractional a) => Colour a -> (a, a, a)

-- | Returns the Y colour coordinate (luminance) for the 2° standard
--   (colourimetric) observer.
luminance :: (Fractional a) => Colour a -> a
data Chromaticity a

-- | Constructs <a>Chromaticity</a> from the CIE little <i>x</i>, little
--   <i>y</i> coordinates for the 2° standard (colourimetric) observer.
mkChromaticity :: (Fractional a) => a -> a -> Chromaticity a

-- | Returns the CIE little <i>x</i>, little <i>y</i>, little <i>z</i>
--   coordinates for the 2° standard (colourimetric) observer.
chromaCoords :: (Fractional a) => Chromaticity a -> (a, a, a)

-- | Returns the CIE little <i>x</i> coordinate for the 2° standard
--   (colourimetric) observer.
chromaX :: (Fractional a) => Chromaticity a -> a

-- | Returns the CIE little <i>y</i> coordinate for the 2° standard
--   (colourimetric) observer.
chromaY :: (Fractional a) => Chromaticity a -> a

-- | Returns the CIE little <i>z</i> coordinate for the 2° standard
--   (colourimetric) observer.
chromaZ :: (Fractional a) => Chromaticity a -> a

-- | Change the type used to represent the chromaticity coordinates.
chromaConvert :: (Fractional b, Real a) => Chromaticity a -> Chromaticity b

-- | Constructs a colour from the given <a>Chromaticity</a> and
--   <a>luminance</a>.
chromaColour :: (Fractional a) => Chromaticity a -> a -> Colour a
instance AffineSpace Chromaticity