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  41 <h1>channel_algorithm.hpp</h1><a href="g_i_l_0016.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment"><a name="l00001"></a>00001 <span class="comment">/*</span>
  42 <a name="l00002"></a>00002 <span class="comment">    Copyright 2005-2007 Adobe Systems Incorporated</span>
  43 <a name="l00003"></a>00003 <span class="comment">   </span>
  44 <a name="l00004"></a>00004 <span class="comment">    Use, modification and distribution are subject to the Boost Software License,</span>
  45 <a name="l00005"></a>00005 <span class="comment">    Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at</span>
  46 <a name="l00006"></a>00006 <span class="comment">    http://www.boost.org/LICENSE_1_0.txt).</span>
  47 <a name="l00007"></a>00007 <span class="comment"></span>
  48 <a name="l00008"></a>00008 <span class="comment">    See http://opensource.adobe.com/gil for most recent version including documentation.</span>
  49 <a name="l00009"></a>00009 <span class="comment">*/</span>
  50 <a name="l00010"></a>00010 <span class="comment">/*************************************************************************************************/</span>
  51 <a name="l00011"></a>00011
  52 <a name="l00012"></a>00012 <span class="preprocessor">#ifndef GIL_CHANNEL_ALGORITHM_HPP</span>
  53 <a name="l00013"></a>00013 <span class="preprocessor"></span><span class="preprocessor">#define GIL_CHANNEL_ALGORITHM_HPP</span>
  54 <a name="l00014"></a>00014 <span class="preprocessor"></span>
  55 <a name="l00025"></a>00025
  56 <a name="l00026"></a>00026 <span class="preprocessor">#include "<a class="code" href="g_i_l_0094.html" title="GIL configuration file.">gil_config.hpp</a>"</span>
  57 <a name="l00027"></a>00027 <span class="preprocessor">#include "<a class="code" href="channel_8hpp.html" title="Channel utilities.">channel.hpp</a>"</span>
  58 <a name="l00028"></a>00028 <span class="preprocessor">#include &lt;boost/mpl/less.hpp&gt;</span>
  59 <a name="l00029"></a>00029 <span class="preprocessor">#include &lt;boost/mpl/integral_c.hpp&gt;</span>
  60 <a name="l00030"></a>00030 <span class="preprocessor">#include &lt;boost/mpl/greater.hpp&gt;</span>
  61 <a name="l00031"></a>00031 <span class="preprocessor">#include &lt;boost/type_traits.hpp&gt;</span>
  62 <a name="l00032"></a>00032
  63 <a name="l00033"></a>00033 <span class="keyword">namespace </span>boost { <span class="keyword">namespace </span>gil {
  64 <a name="l00034"></a>00034
  65 <a name="l00035"></a>00035 <span class="comment">//#ifdef _MSC_VER</span>
  66 <a name="l00036"></a>00036 <span class="comment">//#pragma warning(push)</span>
  67 <a name="l00037"></a>00037 <span class="comment">//#pragma warning(disable: 4309)      // disable truncation of constant value warning (using -1 to get the max value of an integral)</span>
  68 <a name="l00038"></a>00038 <span class="comment">//#endif</span>
  69 <a name="l00039"></a>00039
  70 <a name="l00040"></a>00040 <span class="keyword">namespace </span>detail {
  71 <a name="l00041"></a>00041
  72 <a name="l00042"></a>00042 <span class="comment">// some forward declarations</span>
  73 <a name="l00043"></a>00043 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcChannelV, <span class="keyword">typename</span> DstChannelV, <span class="keywordtype">bool</span> SrcIsIntegral, <span class="keywordtype">bool</span> DstIsIntegral&gt; <span class="keyword">struct </span>channel_converter_unsigned_impl;
  74 <a name="l00044"></a>00044 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcChannelV, <span class="keyword">typename</span> DstChannelV, <span class="keywordtype">bool</span> SrcIsGreater&gt; <span class="keyword">struct </span>channel_converter_unsigned_integral;
  75 <a name="l00045"></a>00045 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcChannelV, <span class="keyword">typename</span> DstChannelV, <span class="keywordtype">bool</span> SrcLessThanDst, <span class="keywordtype">bool</span> SrcDivisible&gt; <span class="keyword">struct </span>channel_converter_unsigned_integral_impl;
  76 <a name="l00046"></a>00046 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcChannelV, <span class="keyword">typename</span> DstChannelV, <span class="keywordtype">bool</span> SrcLessThanDst, <span class="keywordtype">bool</span> CannotFitInInteger&gt; <span class="keyword">struct </span>channel_converter_unsigned_integral_nondivisible;
  77 <a name="l00047"></a>00047
  78 <a name="l00051"></a>00051
  79 <a name="l00052"></a>00052
  80 <a name="l00053"></a>00053 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> Un<span class="keywordtype">signed</span>IntegralChannel&gt;
  81 <a name="l00054"></a>00054 <span class="keyword">struct </span>unsigned_integral_max_value : <span class="keyword">public</span> mpl::integral_c&lt;UnsignedIntegralChannel,-1&gt; {};
  82 <a name="l00055"></a>00055
  83 <a name="l00056"></a>00056 <span class="keyword">template</span> &lt;&gt;
  84 <a name="l00057"></a>00057 <span class="keyword">struct </span>unsigned_integral_max_value&lt;uint8_t&gt; : <span class="keyword">public</span> mpl::integral_c&lt;uint32_t,0xFF&gt; {};
  85 <a name="l00058"></a>00058 <span class="keyword">template</span> &lt;&gt;
  86 <a name="l00059"></a>00059 <span class="keyword">struct </span>unsigned_integral_max_value&lt;uint16_t&gt; : <span class="keyword">public</span> mpl::integral_c&lt;uint32_t,0xFFFF&gt; {};
  87 <a name="l00060"></a>00060 <span class="keyword">template</span> &lt;&gt;
  88 <a name="l00061"></a>00061 <span class="keyword">struct </span>unsigned_integral_max_value&lt;uint32_t&gt; : <span class="keyword">public</span> mpl::integral_c&lt;uintmax_t,0xFFFFFFFF&gt; {};
  89 <a name="l00062"></a>00062
  90 <a name="l00063"></a>00063
  91 <a name="l00064"></a>00064 <span class="keyword">template</span> &lt;<span class="keywordtype">int</span> K&gt;
  92 <a name="l00065"></a>00065 <span class="keyword">struct </span>unsigned_integral_max_value&lt;packed_channel_value&lt;K&gt; &gt;
  93 <a name="l00066"></a>00066     : <span class="keyword">public</span> mpl::integral_c&lt;typename packed_channel_value&lt;K&gt;::integer_t, (1&lt;&lt;K)-1&gt; {};
  94 <a name="l00067"></a>00067
  95 <a name="l00071"></a>00071
  96 <a name="l00072"></a>00072 template &lt;typename UnsignedIntegralChannel&gt;
  97 <a name="l00073"></a>00073 struct unsigned_integral_num_bits : public mpl::int_&lt;sizeof(UnsignedIntegralChannel)*8&gt; {};
  98 <a name="l00074"></a>00074
  99 <a name="l00075"></a>00075 template &lt;int K&gt;
 100 <a name="l00076"></a>00076 struct unsigned_integral_num_bits&lt;packed_channel_value&lt;K&gt; &gt;
 101 <a name="l00077"></a>00077     : public mpl::int_&lt;K&gt; {};
 102 <a name="l00078"></a>00078
 103 <a name="l00079"></a>00079 } <span class="comment">// namespace detail</span>
 104 <a name="l00080"></a>00080
 105 <a name="l00114"></a>00114
 106 <a name="l00115"></a>00115
 107 <a name="l00116"></a>00116
 108 <a name="l00117"></a>00117
 109 <a name="l00118"></a>00118 template &lt;typename SrcChannelV, typename DstChannelV&gt;     <span class="comment">// Model ChannelValueConcept</span>
 110 <a name="l00119"></a>00119 struct channel_converter_unsigned
 111 <a name="l00120"></a>00120     : public detail::channel_converter_unsigned_impl&lt;SrcChannelV,DstChannelV,is_integral&lt;SrcChannelV&gt;::value,is_integral&lt;DstChannelV&gt;::value&gt; {};
 112 <a name="l00121"></a>00121
 113 <a name="l00122"></a>00122
 114 <a name="l00124"></a><a class="code" href="g_i_l_0410.html">00124</a> template &lt;typename T&gt; struct channel_converter_unsigned&lt;T,T&gt; : public detail::identity&lt;T&gt; {};
 115 <a name="l00125"></a>00125
 116 <a name="l00126"></a>00126
 117 <a name="l00127"></a>00127 namespace detail {
 118 <a name="l00128"></a>00128
 119 <a name="l00132"></a>00132
 120 <a name="l00134"></a>00134 template &lt;typename SrcChannelV, typename DstChannelV, bool SrcIsIntegral, bool DstIsIntegral&gt;
 121 <a name="l00135"></a><a class="code" href="g_i_l_0477.html">00135</a> struct channel_converter_unsigned_impl : public std::unary_function&lt;DstChannelV,SrcChannelV&gt; {
 122 <a name="l00136"></a>00136     DstChannelV operator()(SrcChannelV src) const {
 123 <a name="l00137"></a>00137         return DstChannelV(channel_traits&lt;DstChannelV&gt;::min_value() +
 124 <a name="l00138"></a>00138             (src - channel_traits&lt;SrcChannelV&gt;::min_value()) / channel_range&lt;SrcChannelV&gt;() * channel_range&lt;DstChannelV&gt;());
 125 <a name="l00139"></a>00139     }
 126 <a name="l00140"></a>00140 private:
 127 <a name="l00141"></a>00141     template &lt;typename C&gt;
 128 <a name="l00142"></a>00142     static double channel_range() {
 129 <a name="l00143"></a>00143         return double(channel_traits&lt;C&gt;::max_value()) - double(channel_traits&lt;C&gt;::min_value());
 130 <a name="l00144"></a>00144     }
 131 <a name="l00145"></a>00145 };
 132 <a name="l00146"></a>00146
 133 <a name="l00147"></a>00147 <span class="comment">// When both the source and the destination are integral channels, perform a faster conversion</span>
 134 <a name="l00148"></a>00148 template &lt;typename SrcChannelV, typename DstChannelV&gt;
 135 <a name="l00149"></a>00149 struct channel_converter_unsigned_impl&lt;SrcChannelV,DstChannelV,true,true&gt;
 136 <a name="l00150"></a>00150     : public channel_converter_unsigned_integral&lt;SrcChannelV,DstChannelV,
 137 <a name="l00151"></a>00151     mpl::less&lt;unsigned_integral_max_value&lt;SrcChannelV&gt;,unsigned_integral_max_value&lt;DstChannelV&gt; &gt;::value &gt; {};
 138 <a name="l00152"></a>00152
 139 <a name="l00153"></a>00153
 140 <a name="l00157"></a>00157
 141 <a name="l00158"></a>00158 template &lt;typename SrcChannelV, typename DstChannelV&gt;
 142 <a name="l00159"></a>00159 struct channel_converter_unsigned_integral&lt;SrcChannelV,DstChannelV,true&gt;
 143 <a name="l00160"></a>00160     : public channel_converter_unsigned_integral_impl&lt;SrcChannelV,DstChannelV,true,
 144 <a name="l00161"></a>00161     !(unsigned_integral_max_value&lt;DstChannelV&gt;::value % unsigned_integral_max_value&lt;SrcChannelV&gt;::value) &gt; {};
 145 <a name="l00162"></a>00162
 146 <a name="l00163"></a>00163 template &lt;typename SrcChannelV, typename DstChannelV&gt;
 147 <a name="l00164"></a>00164 struct channel_converter_unsigned_integral&lt;SrcChannelV,DstChannelV,false&gt;
 148 <a name="l00165"></a>00165     : public channel_converter_unsigned_integral_impl&lt;SrcChannelV,DstChannelV,false,
 149 <a name="l00166"></a>00166     !(unsigned_integral_max_value&lt;SrcChannelV&gt;::value % unsigned_integral_max_value&lt;DstChannelV&gt;::value) &gt; {};
 150 <a name="l00167"></a>00167
 151 <a name="l00168"></a>00168
 152 <a name="l00172"></a>00172
 153 <a name="l00173"></a>00173 <span class="comment">// Both source and destination are unsigned integral channels, </span>
 154 <a name="l00174"></a>00174 <span class="comment">// the src max value is less than the dst max value,</span>
 155 <a name="l00175"></a>00175 <span class="comment">// and the dst max value is divisible by the src max value</span>
 156 <a name="l00176"></a>00176 template &lt;typename SrcChannelV, typename DstChannelV&gt;
 157 <a name="l00177"></a>00177 struct channel_converter_unsigned_integral_impl&lt;SrcChannelV,DstChannelV,true,true&gt; {
 158 <a name="l00178"></a>00178     DstChannelV operator()(SrcChannelV src) const {
 159 <a name="l00179"></a>00179         typedef typename unsigned_integral_max_value&lt;DstChannelV&gt;::value_type integer_t;
 160 <a name="l00180"></a>00180         static const integer_t mul = unsigned_integral_max_value&lt;DstChannelV&gt;::value / unsigned_integral_max_value&lt;SrcChannelV&gt;::value;
 161 <a name="l00181"></a>00181         return DstChannelV(src * mul);
 162 <a name="l00182"></a>00182     }
 163 <a name="l00183"></a>00183 };
 164 <a name="l00184"></a>00184
 165 <a name="l00185"></a>00185 <span class="comment">// Both source and destination are unsigned integral channels, </span>
 166 <a name="l00186"></a>00186 <span class="comment">// the dst max value is less than (or equal to) the src max value,</span>
 167 <a name="l00187"></a>00187 <span class="comment">// and the src max value is divisible by the dst max value</span>
 168 <a name="l00188"></a>00188 template &lt;typename SrcChannelV, typename DstChannelV&gt;
 169 <a name="l00189"></a>00189 struct channel_converter_unsigned_integral_impl&lt;SrcChannelV,DstChannelV,false,true&gt; {
 170 <a name="l00190"></a>00190     DstChannelV operator()(SrcChannelV src) const {
 171 <a name="l00191"></a>00191         typedef typename unsigned_integral_max_value&lt;SrcChannelV&gt;::value_type integer_t;
 172 <a name="l00192"></a>00192         static const integer_t div = unsigned_integral_max_value&lt;SrcChannelV&gt;::value / unsigned_integral_max_value&lt;DstChannelV&gt;::value;
 173 <a name="l00193"></a>00193         static const integer_t div2 = div/2;
 174 <a name="l00194"></a>00194         return DstChannelV((src + div2) / div);
 175 <a name="l00195"></a>00195     }
 176 <a name="l00196"></a>00196 };
 177 <a name="l00197"></a>00197
 178 <a name="l00198"></a>00198 <span class="comment">// Prevent overflow for the largest integral type</span>
 179 <a name="l00199"></a>00199 template &lt;typename DstChannelV&gt;
 180 <a name="l00200"></a>00200 struct channel_converter_unsigned_integral_impl&lt;uintmax_t,DstChannelV,false,true&gt; {
 181 <a name="l00201"></a>00201     DstChannelV operator()(uintmax_t src) const {
 182 <a name="l00202"></a>00202         static const uintmax_t div = unsigned_integral_max_value&lt;bits32&gt;::value / unsigned_integral_max_value&lt;DstChannelV&gt;::value;
 183 <a name="l00203"></a>00203         static const uintmax_t div2 = div/2;
 184 <a name="l00204"></a>00204         if (src &gt; unsigned_integral_max_value&lt;uintmax_t&gt;::value - div2)
 185 <a name="l00205"></a>00205             return unsigned_integral_max_value&lt;DstChannelV&gt;::value;
 186 <a name="l00206"></a>00206         return DstChannelV((src + div2) / div);
 187 <a name="l00207"></a>00207     }
 188 <a name="l00208"></a>00208 };
 189 <a name="l00209"></a>00209
 190 <a name="l00210"></a>00210 <span class="comment">// Both source and destination are unsigned integral channels, </span>
 191 <a name="l00211"></a>00211 <span class="comment">// and the dst max value is not divisible by the src max value</span>
 192 <a name="l00212"></a>00212 <span class="comment">// See if you can represent the expression (src * dst_max) / src_max in integral form</span>
 193 <a name="l00213"></a>00213 template &lt;typename SrcChannelV, typename DstChannelV, bool SrcLessThanDst&gt;
 194 <a name="l00214"></a>00214 struct channel_converter_unsigned_integral_impl&lt;SrcChannelV,DstChannelV,SrcLessThanDst,false&gt;
 195 <a name="l00215"></a>00215     : public channel_converter_unsigned_integral_nondivisible&lt;SrcChannelV,DstChannelV,SrcLessThanDst,
 196 <a name="l00216"></a>00216     mpl::greater&lt;
 197 <a name="l00217"></a>00217         mpl::plus&lt;unsigned_integral_num_bits&lt;SrcChannelV&gt;,unsigned_integral_num_bits&lt;DstChannelV&gt; &gt;,
 198 <a name="l00218"></a>00218         unsigned_integral_num_bits&lt;uintmax_t&gt;
 199 <a name="l00219"></a>00219     &gt;::value&gt; {};
 200 <a name="l00220"></a>00220
 201 <a name="l00221"></a>00221
 202 <a name="l00222"></a>00222 <span class="comment">// Both source and destination are unsigned integral channels, </span>
 203 <a name="l00223"></a>00223 <span class="comment">// the src max value is less than the dst max value,</span>
 204 <a name="l00224"></a>00224 <span class="comment">// and the dst max value is not divisible by the src max value</span>
 205 <a name="l00225"></a>00225 <span class="comment">// The expression (src * dst_max) / src_max fits in an integer</span>
 206 <a name="l00226"></a>00226 template &lt;typename SrcChannelV, typename DstChannelV&gt;
 207 <a name="l00227"></a>00227 struct channel_converter_unsigned_integral_nondivisible&lt;SrcChannelV,DstChannelV,true,false&gt; {
 208 <a name="l00228"></a>00228     DstChannelV operator()(SrcChannelV src) const {
 209 <a name="l00229"></a>00229         typedef typename detail::min_fast_uint&lt;unsigned_integral_num_bits&lt;SrcChannelV&gt;::value+unsigned_integral_num_bits&lt;DstChannelV&gt;::value&gt;::type integer_t;
 210 <a name="l00230"></a>00230         return DstChannelV(integer_t(src * unsigned_integral_max_value&lt;DstChannelV&gt;::value) / unsigned_integral_max_value&lt;SrcChannelV&gt;::value);
 211 <a name="l00231"></a>00231     }
 212 <a name="l00232"></a>00232 };
 213 <a name="l00233"></a>00233
 214 <a name="l00234"></a>00234 <span class="comment">// Both source and destination are unsigned integral channels, </span>
 215 <a name="l00235"></a>00235 <span class="comment">// the src max value is less than the dst max value,</span>
 216 <a name="l00236"></a>00236 <span class="comment">// and the dst max value is not divisible by the src max value</span>
 217 <a name="l00237"></a>00237 <span class="comment">// The expression (src * dst_max) / src_max cannot fit in an integer (overflows). Use a double</span>
 218 <a name="l00238"></a>00238 template &lt;typename SrcChannelV, typename DstChannelV&gt;
 219 <a name="l00239"></a>00239 struct channel_converter_unsigned_integral_nondivisible&lt;SrcChannelV,DstChannelV,true,true&gt; {
 220 <a name="l00240"></a>00240     DstChannelV operator()(SrcChannelV src) const {
 221 <a name="l00241"></a>00241         static const double mul = unsigned_integral_max_value&lt;DstChannelV&gt;::value / double(unsigned_integral_max_value&lt;SrcChannelV&gt;::value);
 222 <a name="l00242"></a>00242         return DstChannelV(src * mul);
 223 <a name="l00243"></a>00243     }
 224 <a name="l00244"></a>00244 };
 225 <a name="l00245"></a>00245
 226 <a name="l00246"></a>00246
 227 <a name="l00247"></a>00247 <span class="comment">// Both source and destination are unsigned integral channels, </span>
 228 <a name="l00248"></a>00248 <span class="comment">// the dst max value is less than (or equal to) the src max value,</span>
 229 <a name="l00249"></a>00249 <span class="comment">// and the src max value is not divisible by the dst max value</span>
 230 <a name="l00250"></a>00250 template &lt;typename SrcChannelV, typename DstChannelV, bool CannotFit&gt;
 231 <a name="l00251"></a>00251 struct channel_converter_unsigned_integral_nondivisible&lt;SrcChannelV,DstChannelV,false,CannotFit&gt; {
 232 <a name="l00252"></a>00252     DstChannelV operator()(SrcChannelV src) const {
 233 <a name="l00253"></a>00253         typedef typename unsigned_integral_max_value&lt;SrcChannelV&gt;::value_type integer_t;
 234 <a name="l00254"></a>00254
 235 <a name="l00255"></a>00255         static const double div = unsigned_integral_max_value&lt;SrcChannelV&gt;::value / double(unsigned_integral_max_value&lt;DstChannelV&gt;::value);
 236 <a name="l00256"></a>00256         static const integer_t div2 = integer_t(div/2);
 237 <a name="l00257"></a>00257         return DstChannelV((src + div2) / div);
 238 <a name="l00258"></a>00258     }
 239 <a name="l00259"></a>00259 };
 240 <a name="l00260"></a>00260
 241 <a name="l00261"></a>00261 } <span class="comment">// namespace detail</span>
 242 <a name="l00262"></a>00262
 243 <a name="l00266"></a>00266
 244 <a name="l00267"></a><a class="code" href="g_i_l_0414.html">00267</a> template &lt;typename DstChannelV&gt; struct channel_converter_unsigned&lt;bits32f,DstChannelV&gt; : public std::unary_function&lt;bits32f,DstChannelV&gt; {
 245 <a name="l00268"></a>00268     DstChannelV   operator()(bits32f x) const { return DstChannelV(x*channel_traits&lt;DstChannelV&gt;::max_value()+0.5f); }
 246 <a name="l00269"></a>00269 };
 247 <a name="l00270"></a>00270
 248 <a name="l00271"></a>00271 template &lt;typename SrcChannelV&gt; struct channel_converter_unsigned&lt;SrcChannelV,bits32f&gt; : public std::unary_function&lt;SrcChannelV,bits32f&gt; {
 249 <a name="l00272"></a>00272     bits32f operator()(SrcChannelV   x) const { return bits32f(x/float(channel_traits&lt;SrcChannelV&gt;::max_value())); }
 250 <a name="l00273"></a>00273 };
 251 <a name="l00274"></a>00274
 252 <a name="l00275"></a>00275 template &lt;&gt; struct channel_converter_unsigned&lt;bits32f,bits32f&gt; : public std::unary_function&lt;bits32f,bits32f&gt; {
 253 <a name="l00276"></a>00276     bits32f operator()(bits32f   x) const { return x; }
 254 <a name="l00277"></a>00277 };
 255 <a name="l00278"></a>00278
 256 <a name="l00279"></a>00279
 257 <a name="l00281"></a><a class="code" href="g_i_l_0412.html">00281</a> template &lt;&gt; struct channel_converter_unsigned&lt;bits32,bits32f&gt; : public std::unary_function&lt;bits32,bits32f&gt; {
 258 <a name="l00282"></a>00282     bits32f operator()(bits32 x) const {
 259 <a name="l00283"></a>00283         <span class="comment">// unfortunately without an explicit check it is possible to get a round-off error. We must ensure that max_value of bits32 matches max_value of bits32f</span>
 260 <a name="l00284"></a>00284         if (x&gt;=channel_traits&lt;bits32&gt;::max_value()) return <a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits</a>&lt;bits32f&gt;::max_value();
 261 <a name="l00285"></a>00285         return float(x) / float(channel_traits&lt;bits32&gt;::max_value());
 262 <a name="l00286"></a>00286     }
 263 <a name="l00287"></a>00287 };
 264 <a name="l00289"></a><a class="code" href="g_i_l_0416.html">00289</a> template &lt;&gt; struct channel_converter_unsigned&lt;bits32f,bits32&gt; : <span class="keyword">public</span> std::unary_function&lt;bits32f,bits32&gt; {
 265 <a name="l00290"></a>00290     bits32 operator()(<a class="code" href="g_i_l_0620.html" title="A channel adaptor that modifies the range of the source channel. Models: ChannelValueConcept...">bits32f</a> x)<span class="keyword"> const </span>{
 266 <a name="l00291"></a>00291         <span class="comment">// unfortunately without an explicit check it is possible to get a round-off error. We must ensure that max_value of bits32 matches max_value of bits32f</span>
 267 <a name="l00292"></a>00292         <span class="keywordflow">if</span> (x&gt;=<a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits&lt;bits32f&gt;::max_value</a>()) <span class="keywordflow">return</span> <a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits&lt;bits32&gt;::max_value</a>();
 268 <a name="l00293"></a>00293         <span class="keywordflow">return</span> bits32(x * <a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits&lt;bits32&gt;::max_value</a>() + 0.5f);
 269 <a name="l00294"></a>00294     }
 270 <a name="l00295"></a>00295 };
 271 <a name="l00296"></a>00296
 272 <a name="l00298"></a>00298
 273 <a name="l00299"></a>00299 <span class="keyword">namespace </span>detail {
 274 <a name="l00300"></a>00300 <span class="comment">// Converting from signed to unsigned integral channel. </span>
 275 <a name="l00301"></a>00301 <span class="comment">// It is both a unary function, and a metafunction (thus requires the 'type' nested typedef, which equals result_type)</span>
 276 <a name="l00302"></a>00302 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> ChannelValue&gt;     <span class="comment">// Model ChannelValueConcept</span>
 277 <a name="l00303"></a>00303 <span class="keyword">struct </span>channel_convert_to_unsigned : <span class="keyword">public</span> detail::identity&lt;ChannelValue&gt; {
 278 <a name="l00304"></a>00304     <span class="keyword">typedef</span> ChannelValue type;
 279 <a name="l00305"></a>00305 };
 280 <a name="l00306"></a>00306
 281 <a name="l00307"></a>00307 <span class="keyword">template</span> &lt;&gt; <span class="keyword">struct </span>channel_convert_to_unsigned&lt;bits8s&gt; : <span class="keyword">public</span> std::unary_function&lt;bits8s,bits8&gt; {
 282 <a name="l00308"></a>00308     <span class="keyword">typedef</span> bits8 type;
 283 <a name="l00309"></a>00309     type operator()(bits8s  val)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> val+128; }
 284 <a name="l00310"></a>00310 };
 285 <a name="l00311"></a>00311
 286 <a name="l00312"></a>00312 <span class="keyword">template</span> &lt;&gt; <span class="keyword">struct </span>channel_convert_to_unsigned&lt;bits16s&gt; : <span class="keyword">public</span> std::unary_function&lt;bits16s,bits16&gt; {
 287 <a name="l00313"></a>00313     <span class="keyword">typedef</span> bits16 type;
 288 <a name="l00314"></a>00314     type operator()(bits16s  val)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> val+32768; }
 289 <a name="l00315"></a>00315 };
 290 <a name="l00316"></a>00316
 291 <a name="l00317"></a>00317 <span class="keyword">template</span> &lt;&gt; <span class="keyword">struct </span>channel_convert_to_unsigned&lt;bits32s&gt; : <span class="keyword">public</span> std::unary_function&lt;bits32s,bits32&gt; {
 292 <a name="l00318"></a>00318     <span class="keyword">typedef</span> bits32 type;
 293 <a name="l00319"></a>00319     type operator()(bits32s x)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> <span class="keyword">static_cast&lt;</span>bits32<span class="keyword">&gt;</span>(x+(1&lt;&lt;31)); }
 294 <a name="l00320"></a>00320 };
 295 <a name="l00321"></a>00321
 296 <a name="l00322"></a>00322
 297 <a name="l00323"></a>00323 <span class="comment">// Converting from unsigned to signed integral channel</span>
 298 <a name="l00324"></a>00324 <span class="comment">// It is both a unary function, and a metafunction (thus requires the 'type' nested typedef, which equals result_type)</span>
 299 <a name="l00325"></a>00325 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> ChannelValue&gt;     <span class="comment">// Model ChannelValueConcept</span>
 300 <a name="l00326"></a>00326 <span class="keyword">struct </span>channel_convert_from_unsigned : <span class="keyword">public</span> detail::identity&lt;ChannelValue&gt; {
 301 <a name="l00327"></a>00327     <span class="keyword">typedef</span> ChannelValue type;
 302 <a name="l00328"></a>00328 };
 303 <a name="l00329"></a>00329
 304 <a name="l00330"></a>00330 <span class="keyword">template</span> &lt;&gt; <span class="keyword">struct </span>channel_convert_from_unsigned&lt;bits8s&gt; : <span class="keyword">public</span> std::unary_function&lt;bits8,bits8s&gt; {
 305 <a name="l00331"></a>00331     <span class="keyword">typedef</span> bits8s type;
 306 <a name="l00332"></a>00332     type  operator()(bits8  val)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> val-128; }
 307 <a name="l00333"></a>00333 };
 308 <a name="l00334"></a>00334
 309 <a name="l00335"></a>00335 <span class="keyword">template</span> &lt;&gt; <span class="keyword">struct </span>channel_convert_from_unsigned&lt;bits16s&gt; : <span class="keyword">public</span> std::unary_function&lt;bits16,bits16s&gt; {
 310 <a name="l00336"></a>00336     <span class="keyword">typedef</span> bits16s type;
 311 <a name="l00337"></a>00337     type operator()(bits16 val)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> val-32768; }
 312 <a name="l00338"></a>00338 };
 313 <a name="l00339"></a>00339
 314 <a name="l00340"></a>00340 <span class="keyword">template</span> &lt;&gt; <span class="keyword">struct </span>channel_convert_from_unsigned&lt;bits32s&gt; : <span class="keyword">public</span> std::unary_function&lt;bits32,bits32s&gt; {
 315 <a name="l00341"></a>00341     <span class="keyword">typedef</span> bits32s type;
 316 <a name="l00342"></a>00342     type operator()(bits32 x)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> <span class="keyword">static_cast&lt;</span>bits32s<span class="keyword">&gt;</span>(x-(1&lt;&lt;31)); }
 317 <a name="l00343"></a>00343 };
 318 <a name="l00344"></a>00344
 319 <a name="l00345"></a>00345 }   <span class="comment">// namespace detail</span>
 320 <a name="l00346"></a>00346
 321 <a name="l00349"></a>00349 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> SrcChannelV, <span class="keyword">typename</span> DstChannelV&gt; <span class="comment">// Model ChannelValueConcept</span>
 322 <a name="l00350"></a><a class="code" href="g_i_l_0408.html">00350</a> <span class="keyword">struct </span><a class="code" href="g_i_l_0408.html" title="A unary function object converting between channel types.">channel_converter</a> : <span class="keyword">public</span> std::unary_function&lt;SrcChannelV,DstChannelV&gt; {
 323 <a name="l00351"></a>00351     DstChannelV operator()(SrcChannelV src)<span class="keyword"> const </span>{
 324 <a name="l00352"></a>00352         <span class="keyword">typedef</span> detail::channel_convert_to_unsigned&lt;SrcChannelV&gt; to_unsigned;
 325 <a name="l00353"></a>00353         <span class="keyword">typedef</span> detail::channel_convert_from_unsigned&lt;DstChannelV&gt;   from_unsigned;
 326 <a name="l00354"></a>00354         <span class="keyword">typedef</span> channel_converter_unsigned&lt;typename to_unsigned::result_type, typename from_unsigned::argument_type&gt; converter_unsigned;
 327 <a name="l00355"></a>00355         <span class="keywordflow">return</span> from_unsigned()(converter_unsigned()(to_unsigned()(src)));
 328 <a name="l00356"></a>00356     }
 329 <a name="l00357"></a>00357 };
 330 <a name="l00358"></a>00358
 331 <a name="l00361"></a>00361 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> DstChannel, <span class="keyword">typename</span> SrcChannel&gt; <span class="comment">// Model ChannelConcept (could be channel references)</span>
 332 <a name="l00362"></a><a class="code" href="g_i_l_0099.html#gf04e6ac30a35a1f68a8bb84730e34786">00362</a> <span class="keyword">inline</span> <span class="keyword">typename</span> <a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits&lt;DstChannel&gt;::value_type</a> <a class="code" href="g_i_l_0099.html#gf04e6ac30a35a1f68a8bb84730e34786" title="Converting from one channel type to another.">channel_convert</a>(SrcChannel src) {
 333 <a name="l00363"></a>00363     <span class="keywordflow">return</span> <a class="code" href="g_i_l_0408.html" title="A unary function object converting between channel types.">channel_converter&lt;typename channel_traits&lt;SrcChannel&gt;::value_type</a>,
 334 <a name="l00364"></a>00364                              <span class="keyword">typename</span> <a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits&lt;DstChannel&gt;::value_type</a>&gt;()(src);
 335 <a name="l00365"></a>00365 }
 336 <a name="l00366"></a>00366
 337 <a name="l00371"></a><a class="code" href="g_i_l_0450.html">00371</a> <span class="keyword">struct </span><a class="code" href="g_i_l_0450.html" title="Same as channel_converter, except it takes the destination channel by reference,...">default_channel_converter</a> {
 338 <a name="l00372"></a>00372     <span class="keyword">template</span> &lt;<span class="keyword">typename</span> Ch1, <span class="keyword">typename</span> Ch2&gt;
 339 <a name="l00373"></a>00373     <span class="keywordtype">void</span> operator()(<span class="keyword">const</span> Ch1&amp; src, Ch2&amp; dst)<span class="keyword"> const </span>{
 340 <a name="l00374"></a>00374         dst=channel_convert&lt;Ch2&gt;(src);
 341 <a name="l00375"></a>00375     }
 342 <a name="l00376"></a>00376 };
 343 <a name="l00377"></a>00377
 344 <a name="l00378"></a>00378 <span class="keyword">namespace </span>detail {
 345 <a name="l00379"></a>00379     <span class="comment">// fast integer division by 255</span>
 346 <a name="l00380"></a>00380     <span class="keyword">inline</span> uint32_t div255(uint32_t in) { uint32_t tmp=in+128; <span class="keywordflow">return</span> (tmp + (tmp&gt;&gt;8))&gt;&gt;8; }
 347 <a name="l00381"></a>00381
 348 <a name="l00382"></a>00382     <span class="comment">// fast integer divison by 32768</span>
 349 <a name="l00383"></a>00383     <span class="keyword">inline</span> uint32_t div32768(uint32_t in) { <span class="keywordflow">return</span> (in+16384)&gt;&gt;15; }
 350 <a name="l00384"></a>00384 }
 351 <a name="l00385"></a>00385
 352 <a name="l00399"></a>00399
 353 <a name="l00400"></a>00400
 354 <a name="l00402"></a>00402 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> ChannelValue&gt;
 355 <a name="l00403"></a><a class="code" href="g_i_l_0422.html">00403</a> <span class="keyword">struct </span><a class="code" href="g_i_l_0422.html" title="This is the default implementation. Performance specializatons are provided.">channel_multiplier_unsigned</a> : <span class="keyword">public</span> std::binary_function&lt;ChannelValue,ChannelValue,ChannelValue&gt; {
 356 <a name="l00404"></a>00404     ChannelValue operator()(ChannelValue a, ChannelValue b)<span class="keyword"> const </span>{
 357 <a name="l00405"></a>00405         <span class="keywordflow">return</span> ChannelValue(a / <span class="keywordtype">double</span>(<a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits&lt;ChannelValue&gt;::max_value</a>()) * b);
 358 <a name="l00406"></a>00406     }
 359 <a name="l00407"></a>00407 };
 360 <a name="l00408"></a>00408
 361 <a name="l00410"></a><a class="code" href="g_i_l_0428.html">00410</a> <span class="keyword">template</span>&lt;&gt; <span class="keyword">struct </span><a class="code" href="g_i_l_0422.html" title="This is the default implementation. Performance specializatons are provided.">channel_multiplier_unsigned</a>&lt;bits8&gt; : <span class="keyword">public</span> std::binary_function&lt;bits8,bits8,bits8&gt; {
 362 <a name="l00411"></a>00411     bits8 operator()(bits8 a, bits8 b)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> bits8(detail::div255(uint32_t(a) * uint32_t(b))); }
 363 <a name="l00412"></a>00412 };
 364 <a name="l00413"></a>00413
 365 <a name="l00415"></a><a class="code" href="g_i_l_0424.html">00415</a> <span class="keyword">template</span>&lt;&gt; <span class="keyword">struct </span><a class="code" href="g_i_l_0422.html" title="This is the default implementation. Performance specializatons are provided.">channel_multiplier_unsigned</a>&lt;bits16&gt; : <span class="keyword">public</span> std::binary_function&lt;bits16,bits16,bits16&gt; {
 366 <a name="l00416"></a>00416     bits16 operator()(bits16 a, bits16 b)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> bits16((uint32_t(a) * uint32_t(b))/65535); }
 367 <a name="l00417"></a>00417 };
 368 <a name="l00418"></a>00418
 369 <a name="l00420"></a><a class="code" href="g_i_l_0426.html">00420</a> <span class="keyword">template</span>&lt;&gt; <span class="keyword">struct </span><a class="code" href="g_i_l_0422.html" title="This is the default implementation. Performance specializatons are provided.">channel_multiplier_unsigned</a>&lt;<a class="code" href="g_i_l_0620.html" title="A channel adaptor that modifies the range of the source channel. Models: ChannelValueConcept...">bits32f</a>&gt; : <span class="keyword">public</span> std::binary_function&lt;bits32f,bits32f,bits32f&gt; {
 370 <a name="l00421"></a>00421     <a class="code" href="g_i_l_0620.html" title="A channel adaptor that modifies the range of the source channel. Models: ChannelValueConcept...">bits32f</a> operator()(<a class="code" href="g_i_l_0620.html" title="A channel adaptor that modifies the range of the source channel. Models: ChannelValueConcept...">bits32f</a> a, <a class="code" href="g_i_l_0620.html" title="A channel adaptor that modifies the range of the source channel. Models: ChannelValueConcept...">bits32f</a> b)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> a*b; }
 371 <a name="l00422"></a>00422 };
 372 <a name="l00423"></a>00423
 373 <a name="l00425"></a>00425 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> ChannelValue&gt;
 374 <a name="l00426"></a><a class="code" href="g_i_l_0420.html">00426</a> <span class="keyword">struct </span><a class="code" href="g_i_l_0420.html" title="A function object to multiply two channels. result = a * b / max_value.">channel_multiplier</a> : <span class="keyword">public</span> std::binary_function&lt;ChannelValue, ChannelValue, ChannelValue&gt; {
 375 <a name="l00427"></a>00427     ChannelValue operator()(ChannelValue a, ChannelValue b)<span class="keyword"> const </span>{
 376 <a name="l00428"></a>00428         <span class="keyword">typedef</span> detail::channel_convert_to_unsigned&lt;ChannelValue&gt; to_unsigned;
 377 <a name="l00429"></a>00429         <span class="keyword">typedef</span> detail::channel_convert_from_unsigned&lt;ChannelValue&gt;   from_unsigned;
 378 <a name="l00430"></a>00430         <span class="keyword">typedef</span> <a class="code" href="g_i_l_0422.html" title="This is the default implementation. Performance specializatons are provided.">channel_multiplier_unsigned&lt;typename to_unsigned::result_type&gt;</a> multiplier_unsigned;
 379 <a name="l00431"></a>00431         <span class="keywordflow">return</span> from_unsigned()(multiplier_unsigned()(to_unsigned()(a), to_unsigned()(b)));
 380 <a name="l00432"></a>00432     }
 381 <a name="l00433"></a>00433 };
 382 <a name="l00434"></a>00434
 383 <a name="l00436"></a>00436 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> Channel&gt; <span class="comment">// Models ChannelConcept (could be a channel reference)</span>
 384 <a name="l00437"></a><a class="code" href="g_i_l_0103.html#gf73b2a47a7877767534df0eee46dda17">00437</a> <span class="keyword">inline</span> <span class="keyword">typename</span> <a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits&lt;Channel&gt;::value_type</a> <a class="code" href="g_i_l_0103.html#gf73b2a47a7877767534df0eee46dda17" title="A function multiplying two channels. result = a * b / max_value.">channel_multiply</a>(Channel a, Channel b) {
 385 <a name="l00438"></a>00438     <span class="keywordflow">return</span> <a class="code" href="g_i_l_0420.html" title="A function object to multiply two channels. result = a * b / max_value.">channel_multiplier&lt;typename channel_traits&lt;Channel&gt;::value_type</a>&gt;()(a,b);
 386 <a name="l00439"></a>00439 }
 387 <a name="l00441"></a>00441
 388 <a name="l00456"></a>00456
 389 <a name="l00457"></a>00457
 390 <a name="l00458"></a>00458 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> Channel&gt; <span class="comment">// Models ChannelConcept (could be a channel reference)</span>
 391 <a name="l00459"></a><a class="code" href="g_i_l_0101.html#ge2e0267865f89610ef26148874a04bb5">00459</a> <span class="keyword">inline</span> <span class="keyword">typename</span> <a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits&lt;Channel&gt;::value_type</a> <a class="code" href="g_i_l_0101.html#ge2e0267865f89610ef26148874a04bb5" title="Default implementation. Provide overloads for performance.">channel_invert</a>(Channel x) {
 392 <a name="l00460"></a>00460     <span class="keywordflow">return</span> <a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits&lt;Channel&gt;::max_value</a>()-x + <a class="code" href="g_i_l_0429.html" title="Traits for channels. Contains the following members:.">channel_traits&lt;Channel&gt;::min_value</a>();
 393 <a name="l00461"></a>00461 }
 394 <a name="l00462"></a>00462
 395 <a name="l00463"></a>00463 <span class="comment">//#ifdef _MSC_VER</span>
 396 <a name="l00464"></a>00464 <span class="comment">//#pragma warning(pop)</span>
 397 <a name="l00465"></a>00465 <span class="comment">//#endif</span>
 398 <a name="l00466"></a>00466
 399 <a name="l00467"></a>00467 } }  <span class="comment">// namespace boost::gil</span>
 400 <a name="l00468"></a>00468
 401 <a name="l00469"></a>00469 <span class="preprocessor">#endif</span>
 402 </pre></div></div>
 403 <hr size="1"><address style="text-align: right;"><small>Generated on Sat May 2 13:50:13 2009 for Generic Image Library by&nbsp;
 404 <a href="http://www.doxygen.org/index.html">
 405 <img src="doxygen.png" alt="doxygen" align="middle" border="0"></a> 1.5.6 </small></address>
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