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<pre><a name="line-1"></a><span class='hs-comment'>{-
<a name="line-2"></a>Copyright (c) 2008
<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'>-- |Specifies 'Colour's in accordance with the sRGB standard.</span>
<a name="line-24"></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'>SRGB</span>
<a name="line-25"></a> <span class='hs-layout'>(</span><span class='hs-conid'>Colour</span><span class='hs-layout'>,</span> <span class='hs-conid'>RGB</span><span class='hs-layout'>(</span><span class='hs-keyglyph'>..</span><span class='hs-layout'>)</span>
<a name="line-26"></a> <span class='hs-layout'>,</span><span class='hs-varid'>sRGB24</span><span class='hs-layout'>,</span> <span class='hs-varid'>sRGBBounded</span><span class='hs-layout'>,</span> <span class='hs-varid'>sRGB</span>
<a name="line-27"></a> <span class='hs-layout'>,</span><span class='hs-varid'>toSRGB24</span><span class='hs-layout'>,</span> <span class='hs-varid'>toSRGBBounded</span><span class='hs-layout'>,</span> <span class='hs-varid'>toSRGB</span>
<a name="line-28"></a>
<a name="line-29"></a> <span class='hs-layout'>,</span><span class='hs-varid'>sRGB24shows</span><span class='hs-layout'>,</span> <span class='hs-varid'>sRGB24show</span>
<a name="line-30"></a> <span class='hs-layout'>,</span><span class='hs-varid'>sRGB24reads</span><span class='hs-layout'>,</span> <span class='hs-varid'>sRGB24read</span>
<a name="line-31"></a>
<a name="line-32"></a> <span class='hs-layout'>,</span><span class='hs-varid'>sRGBSpace</span>
<a name="line-33"></a> <span class='hs-layout'>)</span>
<a name="line-34"></a><span class='hs-keyword'>where</span>
<a name="line-35"></a>
<a name="line-36"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Data</span><span class='hs-varop'>.</span><span class='hs-conid'>Word</span>
<a name="line-37"></a><span class='hs-keyword'>import</span> <span class='hs-conid'>Numeric</span>
<a name="line-38"></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'>Internal</span> <span class='hs-layout'>(</span><span class='hs-varid'>quantize</span><span class='hs-layout'>)</span>
<a name="line-39"></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-40"></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'>RGBSpace</span> <span class='hs-varid'>hiding</span> <span class='hs-layout'>(</span><span class='hs-varid'>transferFunction</span><span class='hs-layout'>)</span>
<a name="line-41"></a>
<a name="line-42"></a><a name="transferFunction"></a><span class='hs-comment'>{- Non-linear colour space -}</span>
<a name="line-43"></a><span class='hs-comment'>{- the sRGB transfer function approximates a gamma of about 1/2.2 -}</span>
<a name="line-44"></a><span class='hs-definition'>transferFunction</span> <span class='hs-varid'>lin</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>lin</span> <span class='hs-varop'>==</span> <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>1</span>
<a name="line-45"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>lin</span> <span class='hs-varop'><=</span> <span class='hs-num'>0.0031308</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>12.92</span><span class='hs-varop'>*</span><span class='hs-varid'>lin</span>
<a name="line-46"></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'>1</span> <span class='hs-varop'>+</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span><span class='hs-varop'>*</span><span class='hs-varid'>lin</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'>2.4</span><span class='hs-layout'>)</span> <span class='hs-comment'>-</span> <span class='hs-varid'>a</span>
<a name="line-47"></a> <span class='hs-keyword'>where</span>
<a name="line-48"></a> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>0.055</span>
<a name="line-49"></a>
<a name="line-50"></a><a name="invTransferFunction"></a><span class='hs-definition'>invTransferFunction</span> <span class='hs-varid'>nonLin</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>nonLin</span> <span class='hs-varop'>==</span> <span class='hs-num'>1</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>1</span>
<a name="line-51"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>nonLin</span> <span class='hs-varop'><=</span> <span class='hs-num'>0.04045</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>nonLin</span><span class='hs-varop'>/</span><span class='hs-num'>12.92</span>
<a name="line-52"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span>
<a name="line-53"></a> <span class='hs-layout'>(</span><span class='hs-layout'>(</span><span class='hs-varid'>nonLin</span> <span class='hs-varop'>+</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</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-varid'>a</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-varop'>**</span><span class='hs-num'>2.4</span>
<a name="line-54"></a> <span class='hs-keyword'>where</span>
<a name="line-55"></a> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</span> <span class='hs-num'>0.055</span>
<a name="line-56"></a>
<a name="line-57"></a><a name="sRGB"></a><span class='hs-comment'>-- |Construct a colour from an sRGB specification.</span>
<a name="line-58"></a><span class='hs-comment'>-- Input components are expected to be in the range [0..1].</span>
<a name="line-59"></a><span class='hs-definition'>sRGB</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>b</span>
<a name="line-60"></a><span class='hs-definition'>sRGB</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>curryRGB</span> <span class='hs-layout'>(</span><span class='hs-varid'>uncurryRGB</span> <span class='hs-varid'>rgb</span> <span class='hs-varop'>.</span> <span class='hs-varid'>fmap</span> <span class='hs-varid'>invTransferFunction</span><span class='hs-layout'>)</span>
<a name="line-61"></a>
<a name="line-62"></a><a name="sRGBBounded"></a><span class='hs-comment'>-- |Construct a colour from an sRGB specification.</span>
<a name="line-63"></a><span class='hs-comment'>-- Input components are expected to be in the range [0..'maxBound'].</span>
<a name="line-64"></a><span class='hs-definition'>sRGBBounded</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Integral</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Bounded</span> <span class='hs-varid'>a</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span>
<a name="line-65"></a> <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'>b</span>
<a name="line-66"></a><span class='hs-definition'>sRGBBounded</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'>uncurryRGB</span> <span class='hs-varid'>sRGB</span> <span class='hs-layout'>(</span><span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><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-layout'>)</span><span class='hs-layout'>)</span>
<a name="line-67"></a> <span class='hs-keyword'>where</span>
<a name="line-68"></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-varid'>fromIntegral</span> <span class='hs-varid'>x'</span><span class='hs-varop'>/</span><span class='hs-varid'>m</span><span class='hs-layout'>)</span>
<a name="line-69"></a> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fromIntegral</span> <span class='hs-varop'>$</span> <span class='hs-varid'>maxBound</span> <span class='hs-varop'>`asTypeOf`</span> <span class='hs-varid'>r'</span>
<a name="line-70"></a>
<a name="line-71"></a><a name="sRGB24"></a><span class='hs-comment'>-- |Construct a colour from a 24-bit (three 8-bit words) sRGB</span>
<a name="line-72"></a><span class='hs-comment'>-- specification.</span>
<a name="line-73"></a><span class='hs-definition'>sRGB24</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Word8</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Word8</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Word8</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>b</span>
<a name="line-74"></a><span class='hs-definition'>sRGB24</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sRGBBounded</span>
<a name="line-75"></a>
<a name="line-76"></a><a name="toSRGB"></a><span class='hs-comment'>-- |Return the sRGB colour components in the range [0..1].</span>
<a name="line-77"></a><span class='hs-definition'>toSRGB</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RGB</span> <span class='hs-varid'>b</span>
<a name="line-78"></a><span class='hs-definition'>toSRGB</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmap</span> <span class='hs-varid'>transferFunction</span> <span class='hs-layout'>(</span><span class='hs-varid'>toRGB</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span>
<a name="line-79"></a>
<a name="line-80"></a><a name="toSRGBBounded"></a><span class='hs-comment'>{- Results are clamped and quantized -}</span>
<a name="line-81"></a><span class='hs-comment'>-- |Return the approximate sRGB colour components in the range</span>
<a name="line-82"></a><span class='hs-comment'>-- [0..'maxBound'].</span>
<a name="line-83"></a><span class='hs-comment'>-- Out of range values are clamped.</span>
<a name="line-84"></a><span class='hs-definition'>toSRGBBounded</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>RealFrac</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Integral</span> <span class='hs-varid'>a</span><span class='hs-layout'>,</span> <span class='hs-conid'>Bounded</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'>Colour</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RGB</span> <span class='hs-varid'>a</span>
<a name="line-86"></a><span class='hs-definition'>toSRGBBounded</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fmap</span> <span class='hs-varid'>f</span> <span class='hs-layout'>(</span><span class='hs-varid'>toSRGB</span> <span class='hs-varid'>c</span><span class='hs-layout'>)</span>
<a name="line-87"></a> <span class='hs-keyword'>where</span>
<a name="line-88"></a> <span class='hs-varid'>f</span> <span class='hs-varid'>x'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>quantize</span> <span class='hs-layout'>(</span><span class='hs-varid'>m</span><span class='hs-varop'>*</span><span class='hs-varid'>x'</span><span class='hs-layout'>)</span>
<a name="line-89"></a> <span class='hs-varid'>m</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fromIntegral</span> <span class='hs-varop'>$</span> <span class='hs-varid'>maxBound</span> <span class='hs-varop'>`asTypeOf`</span> <span class='hs-layout'>(</span><span class='hs-varid'>f</span> <span class='hs-varid'>undefined</span><span class='hs-layout'>)</span>
<a name="line-90"></a>
<a name="line-91"></a><a name="toSRGB24"></a><span class='hs-comment'>-- |Return the approximate 24-bit sRGB colour components as three 8-bit</span>
<a name="line-92"></a><span class='hs-comment'>-- components.</span>
<a name="line-93"></a><span class='hs-comment'>-- Out of range values are clamped.</span>
<a name="line-94"></a><span class='hs-definition'>toSRGB24</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>RealFrac</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>RGB</span> <span class='hs-conid'>Word8</span>
<a name="line-95"></a><span class='hs-definition'>toSRGB24</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>toSRGBBounded</span>
<a name="line-96"></a>
<a name="line-97"></a><a name="sRGB24shows"></a><span class='hs-comment'>-- |Show a colour in hexadecimal form, e.g. \"#00aaff\"</span>
<a name="line-98"></a><span class='hs-definition'>sRGB24shows</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>RealFrac</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>ShowS</span>
<a name="line-99"></a><span class='hs-definition'>sRGB24shows</span> <span class='hs-varid'>c</span> <span class='hs-keyglyph'>=</span>
<a name="line-100"></a> <span class='hs-layout'>(</span><span class='hs-str'>"#"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>showHex2</span> <span class='hs-varid'>r'</span> <span class='hs-varop'>.</span> <span class='hs-varid'>showHex2</span> <span class='hs-varid'>g'</span> <span class='hs-varop'>.</span> <span class='hs-varid'>showHex2</span> <span class='hs-varid'>b'</span>
<a name="line-101"></a> <span class='hs-keyword'>where</span>
<a name="line-102"></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'>toSRGB24</span> <span class='hs-varid'>c</span>
<a name="line-103"></a> <span class='hs-varid'>showHex2</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-num'>0xf</span> <span class='hs-keyglyph'>=</span> <span class='hs-layout'>(</span><span class='hs-str'>"0"</span><span class='hs-varop'>++</span><span class='hs-layout'>)</span> <span class='hs-varop'>.</span> <span class='hs-varid'>showHex</span> <span class='hs-varid'>x</span>
<a name="line-104"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>showHex</span> <span class='hs-varid'>x</span>
<a name="line-105"></a>
<a name="line-106"></a><a name="sRGB24show"></a><span class='hs-comment'>-- |Show a colour in hexadecimal form, e.g. \"#00aaff\"</span>
<a name="line-107"></a><span class='hs-definition'>sRGB24show</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>RealFrac</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>Colour</span> <span class='hs-varid'>b</span> <span class='hs-keyglyph'>-></span> <span class='hs-conid'>String</span>
<a name="line-108"></a><span class='hs-definition'>sRGB24show</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sRGB24shows</span> <span class='hs-varid'>x</span> <span class='hs-str'>""</span>
<a name="line-109"></a>
<a name="line-110"></a><a name="sRGB24reads"></a><span class='hs-comment'>-- |Read a colour in hexadecimal form, e.g. \"#00aaff\" or \"00aaff\"</span>
<a name="line-111"></a><span class='hs-definition'>sRGB24reads</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>ReadS</span> <span class='hs-layout'>(</span><span class='hs-conid'>Colour</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-112"></a><span class='hs-definition'>sRGB24reads</span> <span class='hs-str'>""</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>[]</span>
<a name="line-113"></a><span class='hs-definition'>sRGB24reads</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>=</span>
<a name="line-114"></a> <span class='hs-keyglyph'>[</span><span class='hs-layout'>(</span><span class='hs-varid'>sRGB24</span> <span class='hs-varid'>a</span> <span class='hs-varid'>b</span> <span class='hs-varid'>c</span><span class='hs-layout'>,</span> <span class='hs-varid'>c0</span><span class='hs-layout'>)</span>
<a name="line-115"></a> <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'>a0</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>readPair</span> <span class='hs-varid'>x'</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varid'>b</span><span class='hs-layout'>,</span><span class='hs-varid'>b0</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>readPair</span> <span class='hs-varid'>a0</span><span class='hs-layout'>,</span> <span class='hs-layout'>(</span><span class='hs-varid'>c</span><span class='hs-layout'>,</span><span class='hs-varid'>c0</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>readPair</span> <span class='hs-varid'>b0</span><span class='hs-keyglyph'>]</span>
<a name="line-116"></a> <span class='hs-keyword'>where</span>
<a name="line-117"></a> <span class='hs-varid'>x'</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>head</span> <span class='hs-varid'>x</span> <span class='hs-varop'>==</span> <span class='hs-chr'>'#'</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>tail</span> <span class='hs-varid'>x</span>
<a name="line-118"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>x</span>
<a name="line-119"></a> <span class='hs-varid'>readPair</span> <span class='hs-conid'>[]</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>[]</span>
<a name="line-120"></a> <span class='hs-varid'>readPair</span> <span class='hs-keyglyph'>[</span><span class='hs-keyword'>_</span><span class='hs-keyglyph'>]</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>[]</span>
<a name="line-121"></a> <span class='hs-varid'>readPair</span> <span class='hs-varid'>a</span> <span class='hs-keyglyph'>=</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'>a1</span><span class='hs-layout'>)</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-str'>""</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'><-</span> <span class='hs-varid'>readHex</span> <span class='hs-varid'>a0</span><span class='hs-keyglyph'>]</span>
<a name="line-122"></a> <span class='hs-keyword'>where</span>
<a name="line-123"></a> <span class='hs-layout'>(</span><span class='hs-varid'>a0</span><span class='hs-layout'>,</span><span class='hs-varid'>a1</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>splitAt</span> <span class='hs-num'>2</span> <span class='hs-varid'>a</span>
<a name="line-124"></a>
<a name="line-125"></a><a name="sRGB24read"></a><span class='hs-comment'>-- |Read a colour in hexadecimal form, e.g. \"#00aaff\" or \"00aaff\"</span>
<a name="line-126"></a><span class='hs-definition'>sRGB24read</span> <span class='hs-keyglyph'>::</span> <span class='hs-layout'>(</span><span class='hs-conid'>Ord</span> <span class='hs-varid'>b</span><span class='hs-layout'>,</span> <span class='hs-conid'>Floating</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=></span> <span class='hs-conid'>String</span> <span class='hs-keyglyph'>-></span> <span class='hs-layout'>(</span><span class='hs-conid'>Colour</span> <span class='hs-varid'>b</span><span class='hs-layout'>)</span>
<a name="line-127"></a><span class='hs-definition'>sRGB24read</span> <span class='hs-varid'>x</span> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>length</span> <span class='hs-varid'>rx</span> <span class='hs-varop'>/=</span> <span class='hs-num'>1</span> <span class='hs-varop'>||</span> <span class='hs-varid'>not</span> <span class='hs-layout'>(</span><span class='hs-varid'>null</span> <span class='hs-layout'>(</span><span class='hs-varid'>snd</span> <span class='hs-layout'>(</span><span class='hs-varid'>head</span> <span class='hs-varid'>rx</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span><span class='hs-layout'>)</span> <span class='hs-keyglyph'>=</span>
<a name="line-128"></a> <span class='hs-varid'>error</span> <span class='hs-str'>"Data.Colour.SRGB.sRGB24read: no parse"</span>
<a name="line-129"></a> <span class='hs-keyglyph'>|</span> <span class='hs-varid'>otherwise</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>fst</span> <span class='hs-layout'>(</span><span class='hs-varid'>head</span> <span class='hs-varid'>rx</span><span class='hs-layout'>)</span>
<a name="line-130"></a> <span class='hs-keyword'>where</span>
<a name="line-131"></a> <span class='hs-varid'>rx</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>sRGB24reads</span> <span class='hs-varid'>x</span>
<a name="line-132"></a>
<a name="line-133"></a><a name="sRGBSpace"></a><span class='hs-comment'>-- |The sRGB colour space</span>
<a name="line-134"></a><span class='hs-definition'>sRGBSpace</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'>RGBSpace</span> <span class='hs-varid'>a</span>
<a name="line-135"></a><span class='hs-definition'>sRGBSpace</span> <span class='hs-keyglyph'>=</span> <span class='hs-varid'>mkRGBSpace</span> <span class='hs-varid'>sRGBGamut</span> <span class='hs-varid'>transfer</span>
<a name="line-136"></a> <span class='hs-keyword'>where</span>
<a name="line-137"></a> <span class='hs-varid'>transfer</span> <span class='hs-keyglyph'>=</span> <span class='hs-conid'>TransferFunction</span> <span class='hs-varid'>transferFunction</span> <span class='hs-varid'>invTransferFunction</span> <span class='hs-layout'>(</span><span class='hs-varid'>recip</span> <span class='hs-num'>2.2</span><span class='hs-layout'>)</span>
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