    {-
    Copyright (c) 2008
    Russell O'Connor

    Permission is hereby granted, free of charge, to any person obtaining a copy
    of this software and associated documentation files (the "Software"), to deal
    in the Software without restriction, including without limitation the rights
    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
    copies of the Software, and to permit persons to whom the Software is
    furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
    THE SOFTWARE.
    -}
    module Data.Colour.CIE.Chromaticity where

    data Chromaticity a = Chroma !a !a deriving (Chromaticity a -> Chromaticity a -> Bool
    (Chromaticity a -> Chromaticity a -> Bool)
    -> (Chromaticity a -> Chromaticity a -> Bool)
    -> Eq (Chromaticity a)
    forall a. Eq a => Chromaticity a -> Chromaticity a -> Bool
    forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
    $c== :: forall a. Eq a => Chromaticity a -> Chromaticity a -> Bool
    == :: Chromaticity a -> Chromaticity a -> Bool
    $c/= :: forall a. Eq a => Chromaticity a -> Chromaticity a -> Bool
    /= :: Chromaticity a -> Chromaticity a -> Bool
    Eq)

    -- |Constructs 'Chromaticity' from the CIE little /x/, little /y/
    -- coordinates for the 2&#176; standard (colourimetric) observer.
    mkChromaticity :: (Fractional a) => a -> a -> Chromaticity a
    mkChromaticity :: forall a. Fractional a => a -> a -> Chromaticity a
    mkChromaticity = a -> a -> Chromaticity a
    forall a. a -> a -> Chromaticity a
    Chroma

    -- |Returns the CIE little /x/, little /y/, little /z/ coordinates
    -- for the 2&#176; standard (colourimetric) observer.
    chromaCoords :: (Fractional a) => Chromaticity a -> (a, a, a)
    chromaCoords :: forall a. Fractional a => Chromaticity a -> (a, a, a)
    chromaCoords (Chroma a
    x a
    y) = (a
    x, a
    y, a
    1 a -> a -> a
    forall a. Num a => a -> a -> a
    - a
    x a -> a -> a
    forall a. Num a => a -> a -> a
    - a
    y)

    -- |Returns the CIE little /x/ coordinate
    -- for the 2&#176; standard (colourimetric) observer.
    chromaX :: (Fractional a) => Chromaticity a -> a
    chromaX :: forall a. Fractional a => Chromaticity a -> a
    chromaX (Chroma a
    x a
    _y) = a
    x

    -- |Returns the CIE little /y/ coordinate
    -- for the 2&#176; standard (colourimetric) observer.
    chromaY :: (Fractional a) => Chromaticity a -> a
    chromaY :: forall a. Fractional a => Chromaticity a -> a
    chromaY (Chroma a
    _x a
    y) = a
    y

    -- |Returns the CIE little /z/ coordinate
    -- for the 2&#176; standard (colourimetric) observer.
    chromaZ :: (Fractional a) => Chromaticity a -> a
    chromaZ :: forall a. Fractional a => Chromaticity a -> a
    chromaZ (Chroma a
    x a
    y) = a
    1 a -> a -> a
    forall a. Num a => a -> a -> a
    - a
    x a -> a -> a
    forall a. Num a => a -> a -> a
    - a
    y

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

    instance (Fractional a, Show a) => Show (Chromaticity a) where
      showsPrec :: Int -> Chromaticity a -> ShowS
    showsPrec Int
    d Chromaticity a
    c = Bool -> ShowS -> ShowS
    showParen (Int
    d Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    > Int
    app_prec) ShowS
    showStr
       where
        showStr :: ShowS
    showStr = String -> ShowS
    showString String
    "mkChromaticity " ShowS -> ShowS -> ShowS
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (Int -> a -> ShowS
    forall a. Show a => Int -> a -> ShowS
    showsPrec (Int
    app_precInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    1) a
    x)
                ShowS -> ShowS -> ShowS
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . String -> ShowS
    showString String
    " "          ShowS -> ShowS -> ShowS
    forall b c a. (b -> c) -> (a -> b) -> a -> c
    . (Int -> a -> ShowS
    forall a. Show a => Int -> a -> ShowS
    showsPrec (Int
    app_precInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    1) a
    y)
        (a
    x,a
    y,a
    z) = Chromaticity a -> (a, a, a)
    forall a. Fractional a => Chromaticity a -> (a, a, a)
    chromaCoords Chromaticity a
    c

    instance (Fractional a, Read a) => Read (Chromaticity a) where
      readsPrec :: Int -> ReadS (Chromaticity a)
    readsPrec Int
    d String
    r = Bool -> ReadS (Chromaticity a) -> ReadS (Chromaticity a)
    forall a. Bool -> ReadS a -> ReadS a
    readParen (Int
    d Int -> Int -> Bool
    forall a. Ord a => a -> a -> Bool
    > Int
    app_prec)
                      (\String
    r -> [(a -> a -> Chromaticity a
    forall a. Fractional a => a -> a -> Chromaticity a
    mkChromaticity a
    x a
    y,String
    t)
                             |(String
    "mkChromaticity",String
    s) <- ReadS String
    lex String
    r
                             ,(a
    x,String
    s0) <- Int -> ReadS a
    forall a. Read a => Int -> ReadS a
    readsPrec (Int
    app_precInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    1) String
    s
                             ,(a
    y,String
    t) <- Int -> ReadS a
    forall a. Read a => Int -> ReadS a
    readsPrec (Int
    app_precInt -> Int -> Int
    forall a. Num a => a -> a -> a
    +Int
    1) String
    s0]) String
    r

    --------------------------------------------------------------------------
    -- not for export
    --------------------------------------------------------------------------

    app_prec :: Int
    app_prec = Int
    10

    infix_prec :: Int
    infix_prec = Int
    9 Int -> Int -> Int
    forall a. a -> a -> a
    `asTypeOf` Int
    app_prec