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<pre><a name="line-1"></a><span class='hs-comment'>{-
<a name="line-2"></a>Copyright (c) 2008, 2009
<a name="line-3"></a>Russell O'Connor
<a name="line-4"></a>
<a name="line-5"></a>Permission is hereby granted, free of charge, to any person obtaining a copy
<a name="line-6"></a>of this software and associated documentation files (the "Software"), to deal
<a name="line-7"></a>in the Software without restriction, including without limitation the rights
<a name="line-8"></a>to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
<a name="line-9"></a>copies of the Software, and to permit persons to whom the Software is
<a name="line-10"></a>furnished to do so, subject to the following conditions:
<a name="line-11"></a>
<a name="line-12"></a>The above copyright notice and this permission notice shall be included in
<a name="line-13"></a>all copies or substantial portions of the Software.
<a name="line-14"></a>
<a name="line-15"></a>THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
<a name="line-16"></a>IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
<a name="line-17"></a>FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
<a name="line-18"></a>AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
<a name="line-19"></a>LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
<a name="line-20"></a>OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
<a name="line-21"></a>THE SOFTWARE.
<a name="line-22"></a>-}</span>
<a name="line-23"></a><span class='hs-comment'>-- |Colour operations defined by the International Commission on </span>
<a name="line-24"></a><span class='hs-comment'>-- Illumination (CIE).</span>
<a name="line-25"></a><span class='hs-keyword'>module</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Colour</span><span class='hs-varop'>.</span><span class='hs-conid'>CIE</span>
<a name="line-26"></a> <span class='hs-layout'>(</span><span class='hs-conid'>Colour</span>
<a name="line-27"></a> <span class='hs-layout'>,</span><span class='hs-varid'>cieXYZ</span><span class='hs-layout'>,</span> <span class='hs-varid'>cieXYZView</span><span class='hs-layout'>,</span> <span class='hs-varid'>luminance</span>
<a name="line-28"></a> <span class='hs-layout'>,</span><span class='hs-varid'>toCIEXYZ</span> <span class='hs-comment'>-- depricated</span>
<a name="line-29"></a>
<a name="line-30"></a> <span class='hs-layout'>,</span><span class='hs-conid'>Chromaticity</span>
<a name="line-31"></a> <span class='hs-layout'>,</span><span class='hs-varid'>mkChromaticity</span><span class='hs-layout'>,</span> <span class='hs-varid'>chromaCoords</span>
<a name="line-32"></a> <span class='hs-layout'>,</span><span class='hs-varid'>chromaX</span><span class='hs-layout'>,</span> <span class='hs-varid'>chromaY</span><span class='hs-layout'>,</span> <span class='hs-varid'>chromaZ</span>
<a name="line-33"></a> <span class='hs-layout'>,</span><span class='hs-varid'>chromaConvert</span>
<a name="line-34"></a> <span class='hs-layout'>,</span><span class='hs-varid'>chromaColour</span>
<a name="line-35"></a>
<a name="line-36"></a> <span class='hs-layout'>,</span><span class='hs-varid'>lightness</span><span class='hs-layout'>,</span> <span class='hs-varid'>cieLABView</span><span class='hs-layout'>,</span> <span class='hs-varid'>cieLAB</span> <span class='hs-varop'>--cieLuv</span>
<a name="line-37"></a> <span class='hs-layout'>)</span>
<a name="line-38"></a><span class='hs-keyword'>where</span>
<a name="line-39"></a>
<a name="line-40"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>List</span>
<a name="line-41"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Colour</span>
<a name="line-42"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Colour</span><span class='hs-varop'>.</span><span class='hs-conid'>RGB</span>
<a name="line-43"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Colour</span><span class='hs-varop'>.</span><span class='hs-conid'>SRGB</span><span class='hs-varop'>.</span><span class='hs-conid'>Linear</span>
<a name="line-44"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Colour</span><span class='hs-varop'>.</span><span class='hs-conid'>CIE</span><span class='hs-varop'>.</span><span class='hs-conid'>Chromaticity</span>
<a name="line-45"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Colour</span><span class='hs-varop'>.</span><span class='hs-conid'>Matrix</span>
<a name="line-46"></a>
<a name="line-47"></a><a name="cieXYZ"></a><span class='hs-comment'>-- |Construct a 'Colour' from XYZ coordinates for the 2&#176; standard</span>
<a name="line-48"></a><span class='hs-comment'>-- (colourimetric) observer.</span>
<a name="line-49"></a><span class='hs-definition'>cieXYZ</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Fractional</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>a</span>
<a name="line-50"></a><span class='hs-definition'>cieXYZ</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span> <span class='hs-varid'>z</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>rgb</span> <span class='hs-varid'>r</span> <span class='hs-varid'>g</span> <span class='hs-varid'>b</span>
<a name="line-51"></a> <span class='hs-keyword'>where</span>
<a name="line-52"></a> <span class='hs-keyglyph'>[</span><span class='hs-varid'>r</span><span class='hs-layout'>,</span><span class='hs-varid'>g</span><span class='hs-layout'>,</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mult</span> <span class='hs-varid'>matrix</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span><span class='hs-varid'>y</span><span class='hs-layout'>,</span><span class='hs-varid'>z</span><span class='hs-keyglyph'>]</span>
<a name="line-53"></a> <span class='hs-varid'>matrix</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>fromRational</span><span class='hs-layout'>)</span> <span class='hs-varid'>xyz2rgb709</span>
<a name="line-54"></a>
<a name="line-55"></a><a name="cieXYZView"></a><span class='hs-comment'>-- |Returns the XYZ colour coordinates for the 2&#176; standard</span>
<a name="line-56"></a><span class='hs-comment'>-- (colourimetric) observer.</span>
<a name="line-57"></a><span class='hs-definition'>cieXYZView</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Fractional</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-58"></a><span class='hs-definition'>cieXYZView</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span><span class='hs-varid'>y</span><span class='hs-layout'>,</span><span class='hs-varid'>z</span><span class='hs-layout'>)</span>
<a name="line-59"></a> <span class='hs-keyword'>where</span>
<a name="line-60"></a> <span class='hs-conid'>RGB</span> <span class='hs-varid'>r</span> <span class='hs-varid'>g</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>toRGB</span> <span class='hs-varid'>c</span>
<a name="line-61"></a> <span class='hs-keyglyph'>[</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span><span class='hs-varid'>y</span><span class='hs-layout'>,</span><span class='hs-varid'>z</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mult</span> <span class='hs-varid'>matrix</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>r</span><span class='hs-layout'>,</span><span class='hs-varid'>g</span><span class='hs-layout'>,</span><span class='hs-varid'>b</span><span class='hs-keyglyph'>]</span>
<a name="line-62"></a> <span class='hs-varid'>matrix</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>map</span> <span class='hs-layout'>(</span><span class='hs-varid'>map</span> <span class='hs-varid'>fromRational</span><span class='hs-layout'>)</span> <span class='hs-varid'>rgb7092xyz</span>
<a name="line-63"></a>
<a name="line-64"></a><a name="toCIEXYZ"></a><span class='hs-comment'>{-# DEPRECATED toCIEXYZ "`toCIEXYZ' has been renamed `cieXYZView'" #-}</span>
<a name="line-65"></a><span class='hs-definition'>toCIEXYZ</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>cieXYZView</span> <span class='hs-varid'>x</span>
<a name="line-66"></a>
<a name="line-67"></a><a name="luminance"></a><span class='hs-comment'>{- CIE luminance -}</span>
<a name="line-68"></a><span class='hs-comment'>-- |Returns the Y colour coordinate (luminance) for the 2&#176; standard</span>
<a name="line-69"></a><span class='hs-comment'>-- (colourimetric) observer.</span>
<a name="line-70"></a><span class='hs-definition'>luminance</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Fractional</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span>
<a name="line-71"></a><span class='hs-definition'>luminance</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>y</span>
<a name="line-72"></a> <span class='hs-keyword'>where</span>
<a name="line-73"></a> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span><span class='hs-varid'>y</span><span class='hs-layout'>,</span><span class='hs-varid'>z</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>toCIEXYZ</span> <span class='hs-varid'>c</span>
<a name="line-74"></a>
<a name="line-75"></a><span class='hs-keyword'>instance</span> <span class='hs-conid'>AffineSpace</span> <span class='hs-conid'>Chromaticity</span> <span class='hs-keyword'>where</span>
<a name="line-76"></a> <span class='hs-varid'>affineCombo</span> <span class='hs-varid'>l</span> <span class='hs-varid'>z</span> <span class='hs-keyglyph'>=</span>
<a name="line-77"></a> <span class='hs-varid'>foldl1'</span> <span class='hs-varid'>chromaAdd</span> <span class='hs-keyglyph'>[</span><span class='hs-varid'>chromaScale</span> <span class='hs-varid'>w</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-varid'>w</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-layout'>(</span><span class='hs-num'>1</span><span class='hs-comment'>-</span><span class='hs-varid'>total</span><span class='hs-layout'>,</span><span class='hs-varid'>z</span><span class='hs-layout'>)</span><span class='hs-conop'>:</span><span class='hs-varid'>l</span><span class='hs-keyglyph'>]</span>
<a name="line-78"></a> <span class='hs-keyword'>where</span>
<a name="line-79"></a> <span class='hs-varid'>total</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sum</span> <span class='hs-varop'>$</span> <span class='hs-varid'>map</span> <span class='hs-varid'>fst</span> <span class='hs-varid'>l</span>
<a name="line-80"></a> <span class='hs-layout'>(</span><span class='hs-conid'>Chroma</span> <span class='hs-varid'>x0</span> <span class='hs-varid'>y0</span><span class='hs-layout'>)</span> <span class='hs-varop'>`chromaAdd`</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chroma</span> <span class='hs-varid'>x1</span> <span class='hs-varid'>y1</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Chroma</span> <span class='hs-layout'>(</span><span class='hs-varid'>x0</span><span class='hs-varop'>+</span><span class='hs-varid'>x1</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>y0</span><span class='hs-varop'>+</span><span class='hs-varid'>y1</span><span class='hs-layout'>)</span>
<a name="line-81"></a> <span class='hs-varid'>s</span> <span class='hs-varop'>`chromaScale`</span> <span class='hs-layout'>(</span><span class='hs-conid'>Chroma</span> <span class='hs-varid'>x</span> <span class='hs-varid'>y</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>Chroma</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span><span class='hs-varop'>*</span><span class='hs-varid'>x</span><span class='hs-layout'>)</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span><span class='hs-varop'>*</span><span class='hs-varid'>y</span><span class='hs-layout'>)</span>
<a name="line-82"></a>
<a name="line-83"></a><a name="chromaColour"></a><span class='hs-comment'>-- |Constructs a colour from the given 'Chromaticity' and 'luminance'.</span>
<a name="line-84"></a><span class='hs-definition'>chromaColour</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Fractional</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span>
<a name="line-85"></a> <span class='hs-conid'>Chromaticity</span> <span class='hs-varid'>a</span>
<a name="line-86"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- ^ 'luminance'</span>
<a name="line-87"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>a</span>
<a name="line-88"></a><span class='hs-definition'>chromaColour</span> <span class='hs-varid'>ch</span> <span class='hs-varid'>y</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>cieXYZ</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span><span class='hs-varop'>*</span><span class='hs-varid'>ch_x</span><span class='hs-layout'>)</span> <span class='hs-varid'>y</span> <span class='hs-layout'>(</span><span class='hs-varid'>s</span><span class='hs-varop'>*</span><span class='hs-varid'>ch_z</span><span class='hs-layout'>)</span>
<a name="line-89"></a> <span class='hs-keyword'>where</span>
<a name="line-90"></a> <span class='hs-layout'>(</span><span class='hs-varid'>ch_x</span><span class='hs-layout'>,</span> <span class='hs-varid'>ch_y</span><span class='hs-layout'>,</span> <span class='hs-varid'>ch_z</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>chromaCoords</span> <span class='hs-varid'>ch</span>
<a name="line-91"></a> <span class='hs-varid'>s</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>y</span><span class='hs-varop'>/</span><span class='hs-varid'>ch_y</span>
<a name="line-92"></a>
<a name="line-93"></a><a name="lightness"></a><span class='hs-comment'>-- |Returns the lightness of a colour with respect to a given white point.</span>
<a name="line-94"></a><span class='hs-comment'>-- Lightness is a perceptually uniform measure.</span>
<a name="line-95"></a><span class='hs-definition'>lightness</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Chromaticity</span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- ^White point</span>
<a name="line-96"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span>
<a name="line-97"></a><span class='hs-definition'>lightness</span> <span class='hs-varid'>white_ch</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-num'>6</span><span class='hs-varop'>/</span><span class='hs-num'>29</span><span class='hs-layout'>)</span><span class='hs-varop'>^</span><span class='hs-num'>3</span> <span class='hs-varop'><</span> <span class='hs-varid'>y'</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>116</span><span class='hs-varop'>*</span><span class='hs-varid'>y'</span><span class='hs-varop'>**</span><span class='hs-layout'>(</span><span class='hs-num'>1</span><span class='hs-varop'>/</span><span class='hs-num'>3</span><span class='hs-layout'>)</span> <span class='hs-comment'>-</span> <span class='hs-num'>16</span>
<a name="line-98"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-num'>29</span><span class='hs-varop'>/</span><span class='hs-num'>3</span><span class='hs-layout'>)</span><span class='hs-varop'>^</span><span class='hs-num'>3</span><span class='hs-varop'>*</span><span class='hs-varid'>y'</span>
<a name="line-99"></a> <span class='hs-keyword'>where</span>
<a name="line-100"></a> <span class='hs-varid'>white</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>chromaColour</span> <span class='hs-varid'>white_ch</span> <span class='hs-num'>1.0</span>
<a name="line-101"></a> <span class='hs-varid'>y'</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>luminance</span> <span class='hs-varid'>c</span><span class='hs-varop'>/</span><span class='hs-varid'>luminance</span> <span class='hs-varid'>white</span><span class='hs-layout'>)</span>
<a name="line-102"></a>
<a name="line-103"></a><a name="cieLABView"></a><span class='hs-comment'>-- |Returns the CIELAB coordinates of a colour, which is a</span>
<a name="line-104"></a><span class='hs-comment'>-- perceptually uniform colour space.</span>
<a name="line-105"></a><span class='hs-comment'>-- The first coordinate is 'lightness'.</span>
<a name="line-106"></a><span class='hs-comment'>-- If you don't know what white point to use, use</span>
<a name="line-107"></a><span class='hs-comment'>-- 'Data.Colour.CIE.Illuminant.d65'.</span>
<a name="line-108"></a><span class='hs-definition'>cieLABView</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Chromaticity</span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- ^White point</span>
<a name="line-109"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-110"></a><span class='hs-definition'>cieLABView</span> <span class='hs-varid'>white_ch</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>lightness</span> <span class='hs-varid'>white_ch</span> <span class='hs-varid'>c</span><span class='hs-layout'>,</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-111"></a> <span class='hs-keyword'>where</span>
<a name="line-112"></a> <span class='hs-varid'>white</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>chromaColour</span> <span class='hs-varid'>white_ch</span> <span class='hs-num'>1.0</span>
<a name="line-113"></a> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span><span class='hs-varid'>y</span><span class='hs-layout'>,</span><span class='hs-varid'>z</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>toCIEXYZ</span> <span class='hs-varid'>c</span>
<a name="line-114"></a> <span class='hs-layout'>(</span><span class='hs-varid'>xn</span><span class='hs-layout'>,</span><span class='hs-varid'>yn</span><span class='hs-layout'>,</span><span class='hs-varid'>zn</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>toCIEXYZ</span> <span class='hs-varid'>white</span>
<a name="line-115"></a> <span class='hs-layout'>(</span><span class='hs-varid'>fx</span><span class='hs-layout'>,</span> <span class='hs-varid'>fy</span><span class='hs-layout'>,</span> <span class='hs-varid'>fz</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-varop'>/</span><span class='hs-varid'>xn</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>y</span><span class='hs-varop'>/</span><span class='hs-varid'>yn</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>z</span><span class='hs-varop'>/</span><span class='hs-varid'>zn</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-116"></a> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>500</span><span class='hs-varop'>*</span><span class='hs-layout'>(</span><span class='hs-varid'>fx</span> <span class='hs-comment'>-</span> <span class='hs-varid'>fy</span><span class='hs-layout'>)</span>
<a name="line-117"></a> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>200</span><span class='hs-varop'>*</span><span class='hs-layout'>(</span><span class='hs-varid'>fy</span> <span class='hs-comment'>-</span> <span class='hs-varid'>fz</span><span class='hs-layout'>)</span>
<a name="line-118"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>|</span> <span class='hs-layout'>(</span><span class='hs-num'>6</span><span class='hs-varop'>/</span><span class='hs-num'>29</span><span class='hs-layout'>)</span><span class='hs-varop'>^</span><span class='hs-num'>3</span> <span class='hs-varop'><</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span><span class='hs-varop'>**</span><span class='hs-layout'>(</span><span class='hs-num'>1</span><span class='hs-varop'>/</span><span class='hs-num'>3</span><span class='hs-layout'>)</span>
<a name="line-119"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>841</span><span class='hs-varop'>/</span><span class='hs-num'>108</span><span class='hs-varop'>*</span><span class='hs-varid'>x</span> <span class='hs-varop'>+</span> <span class='hs-num'>4</span><span class='hs-varop'>/</span><span class='hs-num'>29</span>
<a name="line-120"></a>
<a name="line-121"></a><a name="cieLAB"></a><span class='hs-comment'>-- |Returns the colour for given CIELAB coordinates, which is a</span>
<a name="line-122"></a><span class='hs-comment'>-- perceptually uniform colour space.</span>
<a name="line-123"></a><span class='hs-comment'>-- If you don't know what white point to use, use</span>
<a name="line-124"></a><span class='hs-comment'>-- 'Data.Colour.CIE.Illuminant.d65'.</span>
<a name="line-125"></a><span class='hs-definition'>cieLAB</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Chromaticity</span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- ^White point</span>
<a name="line-126"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- ^L* coordinate (lightness)</span>
<a name="line-127"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- ^a* coordinate</span>
<a name="line-128"></a> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- ^b* coordinate</span>
<a name="line-129"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>a</span>
<a name="line-130"></a><span class='hs-definition'>cieLAB</span> <span class='hs-varid'>white_ch</span> <span class='hs-varid'>l</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>cieXYZ</span> <span class='hs-layout'>(</span><span class='hs-varid'>xn</span><span class='hs-varop'>*</span><span class='hs-varid'>transform</span> <span class='hs-varid'>fx</span><span class='hs-layout'>)</span>
<a name="line-131"></a> <span class='hs-layout'>(</span><span class='hs-varid'>yn</span><span class='hs-varop'>*</span><span class='hs-varid'>transform</span> <span class='hs-varid'>fy</span><span class='hs-layout'>)</span>
<a name="line-132"></a> <span class='hs-layout'>(</span><span class='hs-varid'>zn</span><span class='hs-varop'>*</span><span class='hs-varid'>transform</span> <span class='hs-varid'>fz</span><span class='hs-layout'>)</span>
<a name="line-133"></a> <span class='hs-keyword'>where</span>
<a name="line-134"></a> <span class='hs-varid'>white</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>chromaColour</span> <span class='hs-varid'>white_ch</span> <span class='hs-num'>1.0</span>
<a name="line-135"></a> <span class='hs-layout'>(</span><span class='hs-varid'>xn</span><span class='hs-layout'>,</span><span class='hs-varid'>yn</span><span class='hs-layout'>,</span><span class='hs-varid'>zn</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>toCIEXYZ</span> <span class='hs-varid'>white</span>
<a name="line-136"></a> <span class='hs-varid'>fx</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fy</span> <span class='hs-varop'>+</span> <span class='hs-varid'>a</span><span class='hs-varop'>/</span><span class='hs-num'>500</span>
<a name="line-137"></a> <span class='hs-varid'>fy</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>l</span> <span class='hs-varop'>+</span> <span class='hs-num'>16</span><span class='hs-layout'>)</span><span class='hs-varop'>/</span><span class='hs-num'>116</span>
<a name="line-138"></a> <span class='hs-varid'>fz</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fy</span> <span class='hs-comment'>-</span> <span class='hs-varid'>b</span><span class='hs-varop'>/</span><span class='hs-num'>200</span>
<a name="line-139"></a> <span class='hs-varid'>delta</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>6</span><span class='hs-varop'>/</span><span class='hs-num'>29</span>
<a name="line-140"></a> <span class='hs-varid'>transform</span> <span class='hs-varid'>fa</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>fa</span> <span class='hs-varop'>></span> <span class='hs-varid'>delta</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fa</span><span class='hs-varop'>^</span><span class='hs-num'>3</span>
<a name="line-141"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>fa</span> <span class='hs-comment'>-</span> <span class='hs-num'>16</span><span class='hs-varop'>/</span><span class='hs-num'>116</span><span class='hs-layout'>)</span><span class='hs-varop'>*</span><span class='hs-num'>3</span><span class='hs-varop'>*</span><span class='hs-varid'>delta</span><span class='hs-varop'>^</span><span class='hs-num'>2</span>
<a name="line-142"></a>
<a name="line-143"></a><a name="cieLuv"></a><span class='hs-comment'>-- |Returns the CIELUV coordinates of a colour, which is a</span>
<a name="line-144"></a><span class='hs-comment'>-- perceptually uniform colour space.</span>
<a name="line-145"></a><span class='hs-comment'>-- If you don't know what white point to use, use</span>
<a name="line-146"></a><span class='hs-comment'>-- 'Data.Colour.CIE.Illuminant.d65'.</span>
<a name="line-147"></a><span class='hs-definition'>cieLuv</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Chromaticity</span> <span class='hs-varid'>a</span> <span class='hs-comment'>-- ^White point</span>
<a name="line-148"></a> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-149"></a><span class='hs-definition'>cieLuv</span> <span class='hs-varid'>white_ch</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>l</span><span class='hs-layout'>,</span> <span class='hs-num'>13</span><span class='hs-varop'>*</span><span class='hs-varid'>l</span><span class='hs-varop'>*</span><span class='hs-layout'>(</span><span class='hs-varid'>u'</span><span class='hs-comment'>-</span><span class='hs-varid'>un'</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-num'>13</span><span class='hs-varop'>*</span><span class='hs-varid'>l</span><span class='hs-varop'>*</span><span class='hs-layout'>(</span><span class='hs-varid'>v'</span><span class='hs-comment'>-</span><span class='hs-varid'>vn'</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-150"></a> <span class='hs-keyword'>where</span>
<a name="line-151"></a> <span class='hs-varid'>white</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>chromaColour</span> <span class='hs-varid'>white_ch</span> <span class='hs-num'>1.0</span>
<a name="line-152"></a> <span class='hs-layout'>(</span><span class='hs-varid'>u'</span><span class='hs-layout'>,</span> <span class='hs-varid'>v'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>u'v'</span> <span class='hs-varid'>c</span>
<a name="line-153"></a> <span class='hs-layout'>(</span><span class='hs-varid'>un'</span><span class='hs-layout'>,</span> <span class='hs-varid'>vn'</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>u'v'</span> <span class='hs-varid'>white</span>
<a name="line-154"></a> <span class='hs-varid'>l</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>lightness</span> <span class='hs-varid'>white_ch</span> <span class='hs-varid'>c</span>
<a name="line-155"></a><a name="u'v'"></a><span class='hs-comment'>--------------------------------------------------------------------------</span>
<a name="line-156"></a><span class='hs-comment'>{- not for export -}</span>
<a name="line-157"></a><span class='hs-definition'>u'v'</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-varid'>a</span><span class='hs-layout'>,</span><span class='hs-varid'>a</span><span class='hs-layout'>)</span>
<a name="line-158"></a><span class='hs-definition'>u'v'</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-num'>4</span><span class='hs-varop'>*</span><span class='hs-varid'>x</span><span class='hs-varop'>/</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-varop'>+</span><span class='hs-num'>15</span><span class='hs-varop'>*</span><span class='hs-varid'>y</span><span class='hs-varop'>+</span><span class='hs-num'>3</span><span class='hs-varop'>*</span><span class='hs-varid'>z</span><span class='hs-layout'>)</span><span class='hs-layout'>,</span> <span class='hs-num'>9</span><span class='hs-varop'>*</span><span class='hs-varid'>y</span><span class='hs-varop'>/</span><span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-varop'>+</span><span class='hs-num'>15</span><span class='hs-varop'>*</span><span class='hs-varid'>y</span><span class='hs-varop'>+</span><span class='hs-num'>3</span><span class='hs-varop'>*</span><span class='hs-varid'>z</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-159"></a> <span class='hs-keyword'>where</span>
<a name="line-160"></a> <span class='hs-layout'>(</span><span class='hs-varid'>x</span><span class='hs-layout'>,</span><span class='hs-varid'>y</span><span class='hs-layout'>,</span><span class='hs-varid'>z</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>toCIEXYZ</span> <span class='hs-varid'>c</span>
<a name="line-161"></a>
<a name="line-162"></a><a name="rgb7092xyz"></a><span class='hs-definition'>rgb7092xyz</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-varid'>rgb2xyz</span> <span class='hs-varid'>sRGBGamut</span><span class='hs-layout'>)</span>
<a name="line-163"></a>
<a name="line-164"></a><a name="xyz2rgb709"></a><span class='hs-definition'>xyz2rgb709</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>inverse</span> <span class='hs-varid'>rgb7092xyz</span>
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