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- <div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> <span class="comment">//</span></div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span> <span class="comment">// Copyright 2005-2007 Adobe Systems Incorporated</span></div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span> <span class="comment">//</span></div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span> <span class="comment">// Distributed under the Boost Software License, Version 1.0</span></div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span> <span class="comment">// See accompanying file LICENSE_1_0.txt or copy at</span></div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span> <span class="comment">// http://www.boost.org/LICENSE_1_0.txt</span></div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span> <span class="comment">//</span></div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span> <span class="preprocessor">#ifndef BOOST_GIL_GIL_CHANNEL_ALGORITHM_HPP</span></div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span> <span class="preprocessor">#define BOOST_GIL_GIL_CHANNEL_ALGORITHM_HPP</span></div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span> </div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span> <span class="preprocessor">#include <boost/gil/channel.hpp></span></div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span> <span class="preprocessor">#include <boost/gil/promote_integral.hpp></span></div><div class="line"><a name="l00013"></a><span class="lineno"> 13</span> <span class="preprocessor">#include <boost/gil/typedefs.hpp></span></div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span> <span class="preprocessor">#include <boost/gil/detail/is_channel_integral.hpp></span></div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span> <span class="preprocessor">#include <boost/gil/detail/mp11.hpp></span></div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span> </div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span> <span class="preprocessor">#include <limits></span></div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span> <span class="preprocessor">#include <type_traits></span></div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span> </div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span> <span class="keyword">namespace </span>boost { <span class="keyword">namespace </span>gil {</div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span> </div><div class="line"><a name="l00022"></a><span class="lineno"> 22</span> <span class="keyword">namespace </span>detail {</div><div class="line"><a name="l00023"></a><span class="lineno"> 23</span> </div><div class="line"><a name="l00024"></a><span class="lineno"> 24</span> <span class="comment">// some forward declarations</span></div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span> <span class="keyword">template</span> <<span class="keyword">typename</span> SrcChannelV, <span class="keyword">typename</span> DstChannelV, <span class="keywordtype">bool</span> SrcIsIntegral, <span class="keywordtype">bool</span> DstIsIntegral></div><div class="line"><a name="l00026"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1detail_1_1channel__converter__unsigned__impl.html"> 26</a></span> <span class="keyword">struct </span><a class="code" href="structboost_1_1gil_1_1detail_1_1channel__converter__unsigned__impl.html">channel_converter_unsigned_impl</a>;</div><div class="line"><a name="l00027"></a><span class="lineno"> 27</span> </div><div class="line"><a name="l00028"></a><span class="lineno"> 28</span> <span class="keyword">template</span> <<span class="keyword">typename</span> SrcChannelV, <span class="keyword">typename</span> DstChannelV, <span class="keywordtype">bool</span> SrcIsGreater></div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span> <span class="keyword">struct </span>channel_converter_unsigned_integral;</div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span> </div><div class="line"><a name="l00031"></a><span class="lineno"> 31</span> <span class="keyword">template</span> <<span class="keyword">typename</span> SrcChannelV, <span class="keyword">typename</span> DstChannelV, <span class="keywordtype">bool</span> SrcLessThanDst, <span class="keywordtype">bool</span> SrcDivisible></div><div class="line"><a name="l00032"></a><span class="lineno"> 32</span> <span class="keyword">struct </span>channel_converter_unsigned_integral_impl;</div><div class="line"><a name="l00033"></a><span class="lineno"> 33</span> </div><div class="line"><a name="l00034"></a><span class="lineno"> 34</span> <span class="keyword">template</span> <<span class="keyword">typename</span> SrcChannelV, <span class="keyword">typename</span> DstChannelV, <span class="keywordtype">bool</span> SrcLessThanDst, <span class="keywordtype">bool</span> CannotFitInInteger></div><div class="line"><a name="l00035"></a><span class="lineno"> 35</span> <span class="keyword">struct </span>channel_converter_unsigned_integral_nondivisible;</div><div class="line"><a name="l00036"></a><span class="lineno"> 36</span> </div><div class="line"><a name="l00041"></a><span class="lineno"> 41</span> </div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span> <span class="keyword">template</span> <<span class="keyword">typename</span> Un<span class="keywordtype">signed</span>IntegralChannel></div><div class="line"><a name="l00043"></a><span class="lineno"> 43</span> <span class="keyword">struct </span>unsigned_integral_max_value</div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span>  : std::integral_constant</div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span>  <</div><div class="line"><a name="l00046"></a><span class="lineno"> 46</span>  UnsignedIntegralChannel,</div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span>  (std::numeric_limits<UnsignedIntegralChannel>::max)()</div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span>  ></div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span> {};</div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span> </div><div class="line"><a name="l00051"></a><span class="lineno"> 51</span> <span class="keyword">template</span> <></div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span> <span class="keyword">struct </span>unsigned_integral_max_value<uint8_t></div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span>  : std::integral_constant<uint32_t, 0xFF></div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span> {};</div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span> </div><div class="line"><a name="l00056"></a><span class="lineno"> 56</span> <span class="keyword">template</span> <></div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span> <span class="keyword">struct </span>unsigned_integral_max_value<uint16_t></div><div class="line"><a name="l00058"></a><span class="lineno"> 58</span>  : std::integral_constant<uint32_t, 0xFFFF></div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span> {};</div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span> </div><div class="line"><a name="l00061"></a><span class="lineno"> 61</span> <span class="keyword">template</span> <></div><div class="line"><a name="l00062"></a><span class="lineno"> 62</span> <span class="keyword">struct </span>unsigned_integral_max_value<uint32_t></div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span>  : std::integral_constant<uintmax_t, 0xFFFFFFFF></div><div class="line"><a name="l00064"></a><span class="lineno"> 64</span> {};</div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span> </div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span> <span class="keyword">template</span> <<span class="keywordtype">int</span> K></div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span> <span class="keyword">struct </span>unsigned_integral_max_value<packed_channel_value<K>></div><div class="line"><a name="l00068"></a><span class="lineno"> 68</span>  : std::integral_constant</div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span>  <</div><div class="line"><a name="l00070"></a><span class="lineno"> 70</span>  typename packed_channel_value<K>::integer_t,</div><div class="line"><a name="l00071"></a><span class="lineno"> 71</span>  (uint64_t(1)<<K)-1</div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span>  ></div><div class="line"><a name="l00073"></a><span class="lineno"> 73</span> {};</div><div class="line"><a name="l00074"></a><span class="lineno"> 74</span> </div><div class="line"><a name="l00079"></a><span class="lineno"> 79</span> </div><div class="line"><a name="l00080"></a><span class="lineno"> 80</span> template <typename UnsignedIntegralChannel></div><div class="line"><a name="l00081"></a><span class="lineno"> 81</span> struct unsigned_integral_num_bits</div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span>  : std::integral_constant<int, sizeof(UnsignedIntegralChannel) * 8></div><div class="line"><a name="l00083"></a><span class="lineno"> 83</span> {};</div><div class="line"><a name="l00084"></a><span class="lineno"> 84</span> </div><div class="line"><a name="l00085"></a><span class="lineno"> 85</span> template <int K></div><div class="line"><a name="l00086"></a><span class="lineno"> 86</span> struct unsigned_integral_num_bits<packed_channel_value<K>></div><div class="line"><a name="l00087"></a><span class="lineno"> 87</span>  : std::integral_constant<int, K></div><div class="line"><a name="l00088"></a><span class="lineno"> 88</span> {};</div><div class="line"><a name="l00089"></a><span class="lineno"> 89</span> </div><div class="line"><a name="l00090"></a><span class="lineno"> 90</span> } <span class="comment">// namespace detail</span></div><div class="line"><a name="l00091"></a><span class="lineno"> 91</span> </div><div class="line"><a name="l00115"></a><span class="lineno"> 115</span> </div><div class="line"><a name="l00121"></a><span class="lineno"> 121</span> </div><div class="line"><a name="l00125"></a><span class="lineno"> 125</span> </div><div class="line"><a name="l00126"></a><span class="lineno"> 126</span> template <typename SrcChannelV, typename DstChannelV> <span class="comment">// Model ChannelValueConcept</span></div><div class="line"><a name="l00127"></a><span class="lineno"> 127</span> struct channel_converter_unsigned</div><div class="line"><a name="l00128"></a><span class="lineno"> 128</span>  : detail::channel_converter_unsigned_impl</div><div class="line"><a name="l00129"></a><span class="lineno"> 129</span>  <</div><div class="line"><a name="l00130"></a><span class="lineno"> 130</span>  SrcChannelV,</div><div class="line"><a name="l00131"></a><span class="lineno"> 131</span>  DstChannelV,</div><div class="line"><a name="l00132"></a><span class="lineno"> 132</span>  detail::is_channel_integral<SrcChannelV>::value,</div><div class="line"><a name="l00133"></a><span class="lineno"> 133</span>  detail::is_channel_integral<DstChannelV>::value</div><div class="line"><a name="l00134"></a><span class="lineno"> 134</span>  ></div><div class="line"><a name="l00135"></a><span class="lineno"> 135</span> {};</div><div class="line"><a name="l00136"></a><span class="lineno"> 136</span> </div><div class="line"><a name="l00138"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1channel__converter__unsigned_3_01_t_00_01_t_01_4.html"> 138</a></span> template <typename T> struct channel_converter_unsigned<T,T> : public detail::identity<T> {};</div><div class="line"><a name="l00139"></a><span class="lineno"> 139</span> </div><div class="line"><a name="l00140"></a><span class="lineno"> 140</span> namespace detail {</div><div class="line"><a name="l00141"></a><span class="lineno"> 141</span> </div><div class="line"><a name="l00145"></a><span class="lineno"> 145</span> </div><div class="line"><a name="l00147"></a><span class="lineno"> 147</span> template <typename SrcChannelV, typename DstChannelV, bool SrcIsIntegral, bool DstIsIntegral></div><div class="line"><a name="l00148"></a><span class="lineno"> 148</span> struct channel_converter_unsigned_impl {</div><div class="line"><a name="l00149"></a><span class="lineno"> 149</span>  using argument_type = SrcChannelV;</div><div class="line"><a name="l00150"></a><span class="lineno"> 150</span>  using result_type = DstChannelV;</div><div class="line"><a name="l00151"></a><span class="lineno"> 151</span>  DstChannelV operator()(SrcChannelV src) const {</div><div class="line"><a name="l00152"></a><span class="lineno"> 152</span>  return DstChannelV(channel_traits<DstChannelV>::min_value() +</div><div class="line"><a name="l00153"></a><span class="lineno"> 153</span>  (src - channel_traits<SrcChannelV>::min_value()) / channel_range<SrcChannelV>() * channel_range<DstChannelV>());</div><div class="line"><a name="l00154"></a><span class="lineno"> 154</span>  }</div><div class="line"><a name="l00155"></a><span class="lineno"> 155</span> private:</div><div class="line"><a name="l00156"></a><span class="lineno"> 156</span>  template <typename C></div><div class="line"><a name="l00157"></a><span class="lineno"> 157</span>  static double channel_range() {</div><div class="line"><a name="l00158"></a><span class="lineno"> 158</span>  return double(channel_traits<C>::max_value()) - double(channel_traits<C>::min_value());</div><div class="line"><a name="l00159"></a><span class="lineno"> 159</span>  }</div><div class="line"><a name="l00160"></a><span class="lineno"> 160</span> };</div><div class="line"><a name="l00161"></a><span class="lineno"> 161</span> </div><div class="line"><a name="l00162"></a><span class="lineno"> 162</span> <span class="comment">// When both the source and the destination are integral channels, perform a faster conversion</span></div><div class="line"><a name="l00163"></a><span class="lineno"> 163</span> template <typename SrcChannelV, typename DstChannelV></div><div class="line"><a name="l00164"></a><span class="lineno"> 164</span> struct channel_converter_unsigned_impl<SrcChannelV, DstChannelV, true, true></div><div class="line"><a name="l00165"></a><span class="lineno"> 165</span>  : channel_converter_unsigned_integral</div><div class="line"><a name="l00166"></a><span class="lineno"> 166</span>  <</div><div class="line"><a name="l00167"></a><span class="lineno"> 167</span>  SrcChannelV,</div><div class="line"><a name="l00168"></a><span class="lineno"> 168</span>  DstChannelV,</div><div class="line"><a name="l00169"></a><span class="lineno"> 169</span>  mp11::mp_less</div><div class="line"><a name="l00170"></a><span class="lineno"> 170</span>  <</div><div class="line"><a name="l00171"></a><span class="lineno"> 171</span>  unsigned_integral_max_value<SrcChannelV>,</div><div class="line"><a name="l00172"></a><span class="lineno"> 172</span>  unsigned_integral_max_value<DstChannelV></div><div class="line"><a name="l00173"></a><span class="lineno"> 173</span>  >::value</div><div class="line"><a name="l00174"></a><span class="lineno"> 174</span>  ></div><div class="line"><a name="l00175"></a><span class="lineno"> 175</span> {};</div><div class="line"><a name="l00176"></a><span class="lineno"> 176</span> </div><div class="line"><a name="l00180"></a><span class="lineno"> 180</span> </div><div class="line"><a name="l00181"></a><span class="lineno"> 181</span> template <typename SrcChannelV, typename DstChannelV></div><div class="line"><a name="l00182"></a><span class="lineno"> 182</span> struct channel_converter_unsigned_integral<SrcChannelV,DstChannelV,true></div><div class="line"><a name="l00183"></a><span class="lineno"> 183</span>  : public channel_converter_unsigned_integral_impl<SrcChannelV,DstChannelV,true,</div><div class="line"><a name="l00184"></a><span class="lineno"> 184</span>  !(unsigned_integral_max_value<DstChannelV>::value % unsigned_integral_max_value<SrcChannelV>::value) > {};</div><div class="line"><a name="l00185"></a><span class="lineno"> 185</span> </div><div class="line"><a name="l00186"></a><span class="lineno"> 186</span> template <typename SrcChannelV, typename DstChannelV></div><div class="line"><a name="l00187"></a><span class="lineno"> 187</span> struct channel_converter_unsigned_integral<SrcChannelV,DstChannelV,false></div><div class="line"><a name="l00188"></a><span class="lineno"> 188</span>  : public channel_converter_unsigned_integral_impl<SrcChannelV,DstChannelV,false,</div><div class="line"><a name="l00189"></a><span class="lineno"> 189</span>  !(unsigned_integral_max_value<SrcChannelV>::value % unsigned_integral_max_value<DstChannelV>::value) > {};</div><div class="line"><a name="l00190"></a><span class="lineno"> 190</span> </div><div class="line"><a name="l00191"></a><span class="lineno"> 191</span> </div><div class="line"><a name="l00195"></a><span class="lineno"> 195</span> </div><div class="line"><a name="l00196"></a><span class="lineno"> 196</span> <span class="comment">// Both source and destination are unsigned integral channels,</span></div><div class="line"><a name="l00197"></a><span class="lineno"> 197</span> <span class="comment">// the src max value is less than the dst max value,</span></div><div class="line"><a name="l00198"></a><span class="lineno"> 198</span> <span class="comment">// and the dst max value is divisible by the src max value</span></div><div class="line"><a name="l00199"></a><span class="lineno"> 199</span> template <typename SrcChannelV, typename DstChannelV></div><div class="line"><a name="l00200"></a><span class="lineno"> 200</span> struct channel_converter_unsigned_integral_impl<SrcChannelV,DstChannelV,true,true> {</div><div class="line"><a name="l00201"></a><span class="lineno"> 201</span>  DstChannelV operator()(SrcChannelV src) const {</div><div class="line"><a name="l00202"></a><span class="lineno"> 202</span>  using integer_t = typename unsigned_integral_max_value<DstChannelV>::value_type;</div><div class="line"><a name="l00203"></a><span class="lineno"> 203</span>  static const integer_t mul = unsigned_integral_max_value<DstChannelV>::value / unsigned_integral_max_value<SrcChannelV>::value;</div><div class="line"><a name="l00204"></a><span class="lineno"> 204</span>  return DstChannelV(src * mul);</div><div class="line"><a name="l00205"></a><span class="lineno"> 205</span>  }</div><div class="line"><a name="l00206"></a><span class="lineno"> 206</span> };</div><div class="line"><a name="l00207"></a><span class="lineno"> 207</span> </div><div class="line"><a name="l00208"></a><span class="lineno"> 208</span> <span class="comment">// Both source and destination are unsigned integral channels,</span></div><div class="line"><a name="l00209"></a><span class="lineno"> 209</span> <span class="comment">// the dst max value is less than (or equal to) the src max value,</span></div><div class="line"><a name="l00210"></a><span class="lineno"> 210</span> <span class="comment">// and the src max value is divisible by the dst max value</span></div><div class="line"><a name="l00211"></a><span class="lineno"> 211</span> template <typename SrcChannelV, typename DstChannelV></div><div class="line"><a name="l00212"></a><span class="lineno"> 212</span> struct channel_converter_unsigned_integral_impl<SrcChannelV,DstChannelV,false,true> {</div><div class="line"><a name="l00213"></a><span class="lineno"> 213</span>  DstChannelV operator()(SrcChannelV src) const {</div><div class="line"><a name="l00214"></a><span class="lineno"> 214</span>  using integer_t = typename unsigned_integral_max_value<SrcChannelV>::value_type;</div><div class="line"><a name="l00215"></a><span class="lineno"> 215</span>  static const integer_t div = unsigned_integral_max_value<SrcChannelV>::value / unsigned_integral_max_value<DstChannelV>::value;</div><div class="line"><a name="l00216"></a><span class="lineno"> 216</span>  static const integer_t div2 = div/2;</div><div class="line"><a name="l00217"></a><span class="lineno"> 217</span>  return DstChannelV((src + div2) / div);</div><div class="line"><a name="l00218"></a><span class="lineno"> 218</span>  }</div><div class="line"><a name="l00219"></a><span class="lineno"> 219</span> };</div><div class="line"><a name="l00220"></a><span class="lineno"> 220</span> </div><div class="line"><a name="l00221"></a><span class="lineno"> 221</span> <span class="comment">// Prevent overflow for the largest integral type</span></div><div class="line"><a name="l00222"></a><span class="lineno"> 222</span> template <typename DstChannelV></div><div class="line"><a name="l00223"></a><span class="lineno"> 223</span> struct channel_converter_unsigned_integral_impl<uintmax_t,DstChannelV,false,true> {</div><div class="line"><a name="l00224"></a><span class="lineno"> 224</span>  DstChannelV operator()(uintmax_t src) const {</div><div class="line"><a name="l00225"></a><span class="lineno"> 225</span>  static const uintmax_t div = unsigned_integral_max_value<uint32_t>::value / unsigned_integral_max_value<DstChannelV>::value;</div><div class="line"><a name="l00226"></a><span class="lineno"> 226</span>  static const uintmax_t div2 = div/2;</div><div class="line"><a name="l00227"></a><span class="lineno"> 227</span>  if (src > unsigned_integral_max_value<uintmax_t>::value - div2)</div><div class="line"><a name="l00228"></a><span class="lineno"> 228</span>  return unsigned_integral_max_value<DstChannelV>::value;</div><div class="line"><a name="l00229"></a><span class="lineno"> 229</span>  return DstChannelV((src + div2) / div);</div><div class="line"><a name="l00230"></a><span class="lineno"> 230</span>  }</div><div class="line"><a name="l00231"></a><span class="lineno"> 231</span> };</div><div class="line"><a name="l00232"></a><span class="lineno"> 232</span> </div><div class="line"><a name="l00233"></a><span class="lineno"> 233</span> <span class="comment">// Both source and destination are unsigned integral channels,</span></div><div class="line"><a name="l00234"></a><span class="lineno"> 234</span> <span class="comment">// and the dst max value is not divisible by the src max value</span></div><div class="line"><a name="l00235"></a><span class="lineno"> 235</span> <span class="comment">// See if you can represent the expression (src * dst_max) / src_max in integral form</span></div><div class="line"><a name="l00236"></a><span class="lineno"> 236</span> template <typename SrcChannelV, typename DstChannelV, bool SrcLessThanDst></div><div class="line"><a name="l00237"></a><span class="lineno"> 237</span> struct channel_converter_unsigned_integral_impl<SrcChannelV, DstChannelV, SrcLessThanDst, false></div><div class="line"><a name="l00238"></a><span class="lineno"> 238</span>  : channel_converter_unsigned_integral_nondivisible</div><div class="line"><a name="l00239"></a><span class="lineno"> 239</span>  <</div><div class="line"><a name="l00240"></a><span class="lineno"> 240</span>  SrcChannelV,</div><div class="line"><a name="l00241"></a><span class="lineno"> 241</span>  DstChannelV,</div><div class="line"><a name="l00242"></a><span class="lineno"> 242</span>  SrcLessThanDst,</div><div class="line"><a name="l00243"></a><span class="lineno"> 243</span>  mp11::mp_less</div><div class="line"><a name="l00244"></a><span class="lineno"> 244</span>  <</div><div class="line"><a name="l00245"></a><span class="lineno"> 245</span>  unsigned_integral_num_bits<uintmax_t>,</div><div class="line"><a name="l00246"></a><span class="lineno"> 246</span>  mp11::mp_plus</div><div class="line"><a name="l00247"></a><span class="lineno"> 247</span>  <</div><div class="line"><a name="l00248"></a><span class="lineno"> 248</span>  unsigned_integral_num_bits<SrcChannelV>,</div><div class="line"><a name="l00249"></a><span class="lineno"> 249</span>  unsigned_integral_num_bits<DstChannelV></div><div class="line"><a name="l00250"></a><span class="lineno"> 250</span>  ></div><div class="line"><a name="l00251"></a><span class="lineno"> 251</span>  >::value</div><div class="line"><a name="l00252"></a><span class="lineno"> 252</span>  ></div><div class="line"><a name="l00253"></a><span class="lineno"> 253</span> {};</div><div class="line"><a name="l00254"></a><span class="lineno"> 254</span> </div><div class="line"><a name="l00255"></a><span class="lineno"> 255</span> <span class="comment">// Both source and destination are unsigned integral channels,</span></div><div class="line"><a name="l00256"></a><span class="lineno"> 256</span> <span class="comment">// the src max value is less than the dst max value,</span></div><div class="line"><a name="l00257"></a><span class="lineno"> 257</span> <span class="comment">// and the dst max value is not divisible by the src max value</span></div><div class="line"><a name="l00258"></a><span class="lineno"> 258</span> <span class="comment">// The expression (src * dst_max) / src_max fits in an integer</span></div><div class="line"><a name="l00259"></a><span class="lineno"> 259</span> template <typename SrcChannelV, typename DstChannelV></div><div class="line"><a name="l00260"></a><span class="lineno"> 260</span> struct channel_converter_unsigned_integral_nondivisible<SrcChannelV, DstChannelV, true, false></div><div class="line"><a name="l00261"></a><span class="lineno"> 261</span> {</div><div class="line"><a name="l00262"></a><span class="lineno"> 262</span>  DstChannelV operator()(SrcChannelV src) const</div><div class="line"><a name="l00263"></a><span class="lineno"> 263</span>  {</div><div class="line"><a name="l00264"></a><span class="lineno"> 264</span>  using dest_t = typename base_channel_type<DstChannelV>::type;</div><div class="line"><a name="l00265"></a><span class="lineno"> 265</span>  return DstChannelV(</div><div class="line"><a name="l00266"></a><span class="lineno"> 266</span>  static_cast<dest_t>(src * unsigned_integral_max_value<DstChannelV>::value)</div><div class="line"><a name="l00267"></a><span class="lineno"> 267</span>  / unsigned_integral_max_value<SrcChannelV>::value);</div><div class="line"><a name="l00268"></a><span class="lineno"> 268</span>  }</div><div class="line"><a name="l00269"></a><span class="lineno"> 269</span> };</div><div class="line"><a name="l00270"></a><span class="lineno"> 270</span> </div><div class="line"><a name="l00271"></a><span class="lineno"> 271</span> <span class="comment">// Both source and destination are unsigned integral channels,</span></div><div class="line"><a name="l00272"></a><span class="lineno"> 272</span> <span class="comment">// the src max value is less than the dst max value,</span></div><div class="line"><a name="l00273"></a><span class="lineno"> 273</span> <span class="comment">// and the dst max value is not divisible by the src max value</span></div><div class="line"><a name="l00274"></a><span class="lineno"> 274</span> <span class="comment">// The expression (src * dst_max) / src_max cannot fit in an integer (overflows). Use a double</span></div><div class="line"><a name="l00275"></a><span class="lineno"> 275</span> template <typename SrcChannelV, typename DstChannelV></div><div class="line"><a name="l00276"></a><span class="lineno"> 276</span> struct channel_converter_unsigned_integral_nondivisible<SrcChannelV, DstChannelV, true, true></div><div class="line"><a name="l00277"></a><span class="lineno"> 277</span> {</div><div class="line"><a name="l00278"></a><span class="lineno"> 278</span>  DstChannelV operator()(SrcChannelV src) const</div><div class="line"><a name="l00279"></a><span class="lineno"> 279</span>  {</div><div class="line"><a name="l00280"></a><span class="lineno"> 280</span>  static const double mul</div><div class="line"><a name="l00281"></a><span class="lineno"> 281</span>  = unsigned_integral_max_value<DstChannelV>::value</div><div class="line"><a name="l00282"></a><span class="lineno"> 282</span>  / double(unsigned_integral_max_value<SrcChannelV>::value);</div><div class="line"><a name="l00283"></a><span class="lineno"> 283</span>  return DstChannelV(src * mul);</div><div class="line"><a name="l00284"></a><span class="lineno"> 284</span>  }</div><div class="line"><a name="l00285"></a><span class="lineno"> 285</span> };</div><div class="line"><a name="l00286"></a><span class="lineno"> 286</span> </div><div class="line"><a name="l00287"></a><span class="lineno"> 287</span> <span class="comment">// Both source and destination are unsigned integral channels,</span></div><div class="line"><a name="l00288"></a><span class="lineno"> 288</span> <span class="comment">// the dst max value is less than (or equal to) the src max value,</span></div><div class="line"><a name="l00289"></a><span class="lineno"> 289</span> <span class="comment">// and the src max value is not divisible by the dst max value</span></div><div class="line"><a name="l00290"></a><span class="lineno"> 290</span> template <typename SrcChannelV, typename DstChannelV, bool CannotFit></div><div class="line"><a name="l00291"></a><span class="lineno"> 291</span> struct channel_converter_unsigned_integral_nondivisible<SrcChannelV,DstChannelV,false,CannotFit> {</div><div class="line"><a name="l00292"></a><span class="lineno"> 292</span>  DstChannelV operator()(SrcChannelV src) const {</div><div class="line"><a name="l00293"></a><span class="lineno"> 293</span> </div><div class="line"><a name="l00294"></a><span class="lineno"> 294</span>  using src_integer_t = typename detail::unsigned_integral_max_value<SrcChannelV>::value_type;</div><div class="line"><a name="l00295"></a><span class="lineno"> 295</span>  using dst_integer_t = typename detail::unsigned_integral_max_value<DstChannelV>::value_type;</div><div class="line"><a name="l00296"></a><span class="lineno"> 296</span> </div><div class="line"><a name="l00297"></a><span class="lineno"> 297</span>  static const double div = unsigned_integral_max_value<SrcChannelV>::value</div><div class="line"><a name="l00298"></a><span class="lineno"> 298</span>  / static_cast< double >( unsigned_integral_max_value<DstChannelV>::value );</div><div class="line"><a name="l00299"></a><span class="lineno"> 299</span> </div><div class="line"><a name="l00300"></a><span class="lineno"> 300</span>  static const src_integer_t div2 = static_cast< src_integer_t >( div / 2.0 );</div><div class="line"><a name="l00301"></a><span class="lineno"> 301</span> </div><div class="line"><a name="l00302"></a><span class="lineno"> 302</span>  return DstChannelV( static_cast< dst_integer_t >(( static_cast< double >( src + div2 ) / div )));</div><div class="line"><a name="l00303"></a><span class="lineno"> 303</span>  }</div><div class="line"><a name="l00304"></a><span class="lineno"> 304</span> };</div><div class="line"><a name="l00305"></a><span class="lineno"> 305</span> </div><div class="line"><a name="l00306"></a><span class="lineno"> 306</span> } <span class="comment">// namespace detail</span></div><div class="line"><a name="l00307"></a><span class="lineno"> 307</span> </div><div class="line"><a name="l00311"></a><span class="lineno"> 311</span> </div><div class="line"><a name="l00312"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1channel__converter__unsigned_3_01float32__t_00_01_dst_channel_v_01_4.html"> 312</a></span> template <typename DstChannelV> struct channel_converter_unsigned<float32_t,DstChannelV> {</div><div class="line"><a name="l00313"></a><span class="lineno"> 313</span>  using argument_type = float32_t;</div><div class="line"><a name="l00314"></a><span class="lineno"> 314</span>  using result_type = DstChannelV;</div><div class="line"><a name="l00315"></a><span class="lineno"> 315</span>  DstChannelV operator()(float32_t x) const</div><div class="line"><a name="l00316"></a><span class="lineno"> 316</span>  {</div><div class="line"><a name="l00317"></a><span class="lineno"> 317</span>  using dst_integer_t = typename detail::unsigned_integral_max_value<DstChannelV>::value_type;</div><div class="line"><a name="l00318"></a><span class="lineno"> 318</span>  return DstChannelV( static_cast< dst_integer_t >(x*channel_traits<DstChannelV>::max_value()+0.5f ));</div><div class="line"><a name="l00319"></a><span class="lineno"> 319</span>  }</div><div class="line"><a name="l00320"></a><span class="lineno"> 320</span> };</div><div class="line"><a name="l00321"></a><span class="lineno"> 321</span> </div><div class="line"><a name="l00322"></a><span class="lineno"> 322</span> template <typename SrcChannelV> struct channel_converter_unsigned<SrcChannelV,float32_t> {</div><div class="line"><a name="l00323"></a><span class="lineno"> 323</span>  using argument_type = float32_t;</div><div class="line"><a name="l00324"></a><span class="lineno"> 324</span>  using result_type = SrcChannelV;</div><div class="line"><a name="l00325"></a><span class="lineno"> 325</span>  float32_t operator()(SrcChannelV x) const { return float32_t(x/float(channel_traits<SrcChannelV>::max_value())); }</div><div class="line"><a name="l00326"></a><span class="lineno"> 326</span> };</div><div class="line"><a name="l00327"></a><span class="lineno"> 327</span> </div><div class="line"><a name="l00328"></a><span class="lineno"> 328</span> template <> struct channel_converter_unsigned<float32_t,float32_t> {</div><div class="line"><a name="l00329"></a><span class="lineno"> 329</span>  using argument_type = float32_t;</div><div class="line"><a name="l00330"></a><span class="lineno"> 330</span>  using result_type = float32_t;</div><div class="line"><a name="l00331"></a><span class="lineno"> 331</span>  float32_t operator()(float32_t x) const { return x; }</div><div class="line"><a name="l00332"></a><span class="lineno"> 332</span> };</div><div class="line"><a name="l00333"></a><span class="lineno"> 333</span> </div><div class="line"><a name="l00334"></a><span class="lineno"> 334</span> </div><div class="line"><a name="l00336"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1channel__converter__unsigned_3_01uint32__t_00_01float32__t_01_4.html"> 336</a></span> template <> struct channel_converter_unsigned<uint32_t,float32_t> {</div><div class="line"><a name="l00337"></a><span class="lineno"> 337</span>  using argument_type = uint32_t;</div><div class="line"><a name="l00338"></a><span class="lineno"> 338</span>  using result_type = float32_t;</div><div class="line"><a name="l00339"></a><span class="lineno"> 339</span>  float32_t operator()(uint32_t x) const {</div><div class="line"><a name="l00340"></a><span class="lineno"> 340</span>  <span class="comment">// unfortunately without an explicit check it is possible to get a round-off error. We must ensure that max_value of uint32_t matches max_value of float32_t</span></div><div class="line"><a name="l00341"></a><span class="lineno"> 341</span>  if (x>=channel_traits<uint32_t>::max_value()) return channel_traits<float32_t>::max_value();</div><div class="line"><a name="l00342"></a><span class="lineno"> 342</span>  return float(x) / float(channel_traits<uint32_t>::max_value());</div><div class="line"><a name="l00343"></a><span class="lineno"> 343</span>  }</div><div class="line"><a name="l00344"></a><span class="lineno"> 344</span> };</div><div class="line"><a name="l00346"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1channel__converter__unsigned_3_01float32__t_00_01uint32__t_01_4.html"> 346</a></span> template <> struct channel_converter_unsigned<float32_t,uint32_t> {</div><div class="line"><a name="l00347"></a><span class="lineno"> 347</span>  <span class="keyword">using</span> argument_type = <a class="code" href="group___channel_model.html#gaa70e2f51d4342cd54a28684f20c6135b">float32_t</a>;</div><div class="line"><a name="l00348"></a><span class="lineno"> 348</span>  <span class="keyword">using</span> result_type = uint32_t;</div><div class="line"><a name="l00349"></a><span class="lineno"> 349</span>  uint32_t operator()(<a class="code" href="group___channel_model.html#gaa70e2f51d4342cd54a28684f20c6135b">float32_t</a> x)<span class="keyword"> const </span>{</div><div class="line"><a name="l00350"></a><span class="lineno"> 350</span>  <span class="comment">// unfortunately without an explicit check it is possible to get a round-off error. We must ensure that max_value of uint32_t matches max_value of float32_t</span></div><div class="line"><a name="l00351"></a><span class="lineno"> 351</span>  <span class="keywordflow">if</span> (x>=channel_traits<float32_t>::max_value())</div><div class="line"><a name="l00352"></a><span class="lineno"> 352</span>  <span class="keywordflow">return</span> channel_traits<uint32_t>::max_value();</div><div class="line"><a name="l00353"></a><span class="lineno"> 353</span> </div><div class="line"><a name="l00354"></a><span class="lineno"> 354</span>  <span class="keyword">auto</span> <span class="keyword">const</span> max_value = channel_traits<uint32_t>::max_value();</div><div class="line"><a name="l00355"></a><span class="lineno"> 355</span>  <span class="keyword">auto</span> <span class="keyword">const</span> result = x * static_cast<float32_t::base_channel_t>(max_value) + 0.5f;</div><div class="line"><a name="l00356"></a><span class="lineno"> 356</span>  <span class="keywordflow">return</span> static_cast<uint32_t>(result);</div><div class="line"><a name="l00357"></a><span class="lineno"> 357</span>  }</div><div class="line"><a name="l00358"></a><span class="lineno"> 358</span> };</div><div class="line"><a name="l00359"></a><span class="lineno"> 359</span> </div><div class="line"><a name="l00361"></a><span class="lineno"> 361</span> </div><div class="line"><a name="l00362"></a><span class="lineno"> 362</span> <span class="keyword">namespace </span>detail {</div><div class="line"><a name="l00363"></a><span class="lineno"> 363</span> <span class="comment">// Converting from signed to unsigned integral channel.</span></div><div class="line"><a name="l00364"></a><span class="lineno"> 364</span> <span class="comment">// It is both a unary function, and a metafunction (thus requires the 'type' nested alias, which equals result_type)</span></div><div class="line"><a name="l00365"></a><span class="lineno"> 365</span> <span class="keyword">template</span> <<span class="keyword">typename</span> ChannelValue> <span class="comment">// Model ChannelValueConcept</span></div><div class="line"><a name="l00366"></a><span class="lineno"> 366</span> <span class="keyword">struct </span>channel_convert_to_unsigned : <span class="keyword">public</span> <a class="code" href="structboost_1_1gil_1_1detail_1_1identity.html">detail::identity</a><ChannelValue> {</div><div class="line"><a name="l00367"></a><span class="lineno"> 367</span>  <span class="keyword">using</span> type = ChannelValue;</div><div class="line"><a name="l00368"></a><span class="lineno"> 368</span> };</div><div class="line"><a name="l00369"></a><span class="lineno"> 369</span> </div><div class="line"><a name="l00370"></a><span class="lineno"> 370</span> <span class="keyword">template</span> <> <span class="keyword">struct </span>channel_convert_to_unsigned<int8_t> {</div><div class="line"><a name="l00371"></a><span class="lineno"> 371</span>  <span class="keyword">using</span> argument_type = int8_t;</div><div class="line"><a name="l00372"></a><span class="lineno"> 372</span>  <span class="keyword">using</span> result_type = uint8_t;</div><div class="line"><a name="l00373"></a><span class="lineno"> 373</span>  <span class="keyword">using</span> type = uint8_t;</div><div class="line"><a name="l00374"></a><span class="lineno"> 374</span>  type operator()(int8_t val)<span class="keyword"> const </span>{</div><div class="line"><a name="l00375"></a><span class="lineno"> 375</span>  <span class="keywordflow">return</span> static_cast<uint8_t>(static_cast<uint32_t>(val) + 128u);</div><div class="line"><a name="l00376"></a><span class="lineno"> 376</span>  }</div><div class="line"><a name="l00377"></a><span class="lineno"> 377</span> };</div><div class="line"><a name="l00378"></a><span class="lineno"> 378</span> </div><div class="line"><a name="l00379"></a><span class="lineno"> 379</span> <span class="keyword">template</span> <> <span class="keyword">struct </span>channel_convert_to_unsigned<int16_t> {</div><div class="line"><a name="l00380"></a><span class="lineno"> 380</span>  <span class="keyword">using</span> argument_type = int16_t;</div><div class="line"><a name="l00381"></a><span class="lineno"> 381</span>  <span class="keyword">using</span> result_type = uint16_t;</div><div class="line"><a name="l00382"></a><span class="lineno"> 382</span>  <span class="keyword">using</span> type = uint16_t;</div><div class="line"><a name="l00383"></a><span class="lineno"> 383</span>  type operator()(int16_t val)<span class="keyword"> const </span>{</div><div class="line"><a name="l00384"></a><span class="lineno"> 384</span>  <span class="keywordflow">return</span> static_cast<uint16_t>(static_cast<uint32_t>(val) + 32768u);</div><div class="line"><a name="l00385"></a><span class="lineno"> 385</span>  }</div><div class="line"><a name="l00386"></a><span class="lineno"> 386</span> };</div><div class="line"><a name="l00387"></a><span class="lineno"> 387</span> </div><div class="line"><a name="l00388"></a><span class="lineno"> 388</span> <span class="keyword">template</span> <> <span class="keyword">struct </span>channel_convert_to_unsigned<int32_t> {</div><div class="line"><a name="l00389"></a><span class="lineno"> 389</span>  <span class="keyword">using</span> argument_type = int32_t;</div><div class="line"><a name="l00390"></a><span class="lineno"> 390</span>  <span class="keyword">using</span> result_type = uint32_t;</div><div class="line"><a name="l00391"></a><span class="lineno"> 391</span>  <span class="keyword">using</span> type = uint32_t;</div><div class="line"><a name="l00392"></a><span class="lineno"> 392</span>  type operator()(int32_t val)<span class="keyword"> const </span>{</div><div class="line"><a name="l00393"></a><span class="lineno"> 393</span>  <span class="keywordflow">return</span> static_cast<uint32_t>(val)+(1u<<31);</div><div class="line"><a name="l00394"></a><span class="lineno"> 394</span>  }</div><div class="line"><a name="l00395"></a><span class="lineno"> 395</span> };</div><div class="line"><a name="l00396"></a><span class="lineno"> 396</span> </div><div class="line"><a name="l00397"></a><span class="lineno"> 397</span> </div><div class="line"><a name="l00398"></a><span class="lineno"> 398</span> <span class="comment">// Converting from unsigned to signed integral channel</span></div><div class="line"><a name="l00399"></a><span class="lineno"> 399</span> <span class="comment">// It is both a unary function, and a metafunction (thus requires the 'type' nested alias, which equals result_type)</span></div><div class="line"><a name="l00400"></a><span class="lineno"> 400</span> <span class="keyword">template</span> <<span class="keyword">typename</span> ChannelValue> <span class="comment">// Model ChannelValueConcept</span></div><div class="line"><a name="l00401"></a><span class="lineno"> 401</span> <span class="keyword">struct </span>channel_convert_from_unsigned : <span class="keyword">public</span> detail::identity<ChannelValue> {</div><div class="line"><a name="l00402"></a><span class="lineno"> 402</span>  <span class="keyword">using</span> type = ChannelValue;</div><div class="line"><a name="l00403"></a><span class="lineno"> 403</span> };</div><div class="line"><a name="l00404"></a><span class="lineno"> 404</span> </div><div class="line"><a name="l00405"></a><span class="lineno"> 405</span> <span class="keyword">template</span> <> <span class="keyword">struct </span>channel_convert_from_unsigned<int8_t> {</div><div class="line"><a name="l00406"></a><span class="lineno"> 406</span>  <span class="keyword">using</span> argument_type = uint8_t;</div><div class="line"><a name="l00407"></a><span class="lineno"> 407</span>  <span class="keyword">using</span> result_type = int8_t;</div><div class="line"><a name="l00408"></a><span class="lineno"> 408</span>  <span class="keyword">using</span> type = int8_t;</div><div class="line"><a name="l00409"></a><span class="lineno"> 409</span>  type operator()(uint8_t val)<span class="keyword"> const </span>{</div><div class="line"><a name="l00410"></a><span class="lineno"> 410</span>  <span class="keywordflow">return</span> static_cast<int8_t>(static_cast<int32_t>(val) - 128);</div><div class="line"><a name="l00411"></a><span class="lineno"> 411</span>  }</div><div class="line"><a name="l00412"></a><span class="lineno"> 412</span> };</div><div class="line"><a name="l00413"></a><span class="lineno"> 413</span> </div><div class="line"><a name="l00414"></a><span class="lineno"> 414</span> <span class="keyword">template</span> <> <span class="keyword">struct </span>channel_convert_from_unsigned<int16_t> {</div><div class="line"><a name="l00415"></a><span class="lineno"> 415</span>  <span class="keyword">using</span> argument_type = uint16_t;</div><div class="line"><a name="l00416"></a><span class="lineno"> 416</span>  <span class="keyword">using</span> result_type = int16_t;</div><div class="line"><a name="l00417"></a><span class="lineno"> 417</span>  <span class="keyword">using</span> type = int16_t;</div><div class="line"><a name="l00418"></a><span class="lineno"> 418</span>  type operator()(uint16_t val)<span class="keyword"> const </span>{</div><div class="line"><a name="l00419"></a><span class="lineno"> 419</span>  <span class="keywordflow">return</span> static_cast<int16_t>(static_cast<int32_t>(val) - 32768);</div><div class="line"><a name="l00420"></a><span class="lineno"> 420</span>  }</div><div class="line"><a name="l00421"></a><span class="lineno"> 421</span> };</div><div class="line"><a name="l00422"></a><span class="lineno"> 422</span> </div><div class="line"><a name="l00423"></a><span class="lineno"> 423</span> <span class="keyword">template</span> <> <span class="keyword">struct </span>channel_convert_from_unsigned<int32_t> {</div><div class="line"><a name="l00424"></a><span class="lineno"> 424</span>  <span class="keyword">using</span> argument_type = uint32_t;</div><div class="line"><a name="l00425"></a><span class="lineno"> 425</span>  <span class="keyword">using</span> result_type = int32_t;</div><div class="line"><a name="l00426"></a><span class="lineno"> 426</span>  <span class="keyword">using</span> type = int32_t;</div><div class="line"><a name="l00427"></a><span class="lineno"> 427</span>  type operator()(uint32_t val)<span class="keyword"> const </span>{</div><div class="line"><a name="l00428"></a><span class="lineno"> 428</span>  <span class="keywordflow">return</span> static_cast<int32_t>(val - (1u<<31));</div><div class="line"><a name="l00429"></a><span class="lineno"> 429</span>  }</div><div class="line"><a name="l00430"></a><span class="lineno"> 430</span> };</div><div class="line"><a name="l00431"></a><span class="lineno"> 431</span> </div><div class="line"><a name="l00432"></a><span class="lineno"> 432</span> } <span class="comment">// namespace detail</span></div><div class="line"><a name="l00433"></a><span class="lineno"> 433</span> </div><div class="line"><a name="l00436"></a><span class="lineno"> 436</span> <span class="keyword">template</span> <<span class="keyword">typename</span> SrcChannelV, <span class="keyword">typename</span> DstChannelV> <span class="comment">// Model ChannelValueConcept</span></div><div class="line"><a name="l00437"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1channel__converter.html"> 437</a></span> <span class="keyword">struct </span><a class="code" href="structboost_1_1gil_1_1channel__converter.html">channel_converter</a> {</div><div class="line"><a name="l00438"></a><span class="lineno"> 438</span>  <span class="keyword">using</span> argument_type = SrcChannelV;</div><div class="line"><a name="l00439"></a><span class="lineno"> 439</span>  <span class="keyword">using</span> result_type = DstChannelV;</div><div class="line"><a name="l00440"></a><span class="lineno"> 440</span>  DstChannelV operator()(<span class="keyword">const</span> SrcChannelV& src)<span class="keyword"> const </span>{</div><div class="line"><a name="l00441"></a><span class="lineno"> 441</span>  <span class="keyword">using</span> to_unsigned = detail::channel_convert_to_unsigned<SrcChannelV>;</div><div class="line"><a name="l00442"></a><span class="lineno"> 442</span>  <span class="keyword">using</span> from_unsigned = detail::channel_convert_from_unsigned<DstChannelV>;</div><div class="line"><a name="l00443"></a><span class="lineno"> 443</span>  <span class="keyword">using</span> converter_unsigned = channel_converter_unsigned<typename to_unsigned::result_type, typename from_unsigned::argument_type>;</div><div class="line"><a name="l00444"></a><span class="lineno"> 444</span>  <span class="keywordflow">return</span> from_unsigned()(converter_unsigned()(to_unsigned()(src)));</div><div class="line"><a name="l00445"></a><span class="lineno"> 445</span>  }</div><div class="line"><a name="l00446"></a><span class="lineno"> 446</span> };</div><div class="line"><a name="l00447"></a><span class="lineno"> 447</span> </div><div class="line"><a name="l00450"></a><span class="lineno"> 450</span> <span class="keyword">template</span> <<span class="keyword">typename</span> DstChannel, <span class="keyword">typename</span> SrcChannel> <span class="comment">// Model ChannelConcept (could be channel references)</span></div><div class="line"><a name="l00451"></a><span class="lineno"><a class="line" href="group___channel_convert_algorithm.html#ga1ca10b1d27bc2f2ce4906b8890e613a5"> 451</a></span> <span class="keyword">inline</span> <span class="keyword">typename</span> channel_traits<DstChannel>::value_type <a class="code" href="group___channel_convert_algorithm.html#ga1ca10b1d27bc2f2ce4906b8890e613a5">channel_convert</a>(<span class="keyword">const</span> SrcChannel& src) {</div><div class="line"><a name="l00452"></a><span class="lineno"> 452</span>  <span class="keywordflow">return</span> <a class="code" href="structboost_1_1gil_1_1channel__converter.html">channel_converter<typename channel_traits<SrcChannel>::value_type</a>,</div><div class="line"><a name="l00453"></a><span class="lineno"> 453</span>  <span class="keyword">typename</span> channel_traits<DstChannel>::value_type>()(src);</div><div class="line"><a name="l00454"></a><span class="lineno"> 454</span> }</div><div class="line"><a name="l00455"></a><span class="lineno"> 455</span> </div><div class="line"><a name="l00460"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1default__channel__converter.html"> 460</a></span> <span class="keyword">struct </span><a class="code" href="structboost_1_1gil_1_1default__channel__converter.html">default_channel_converter</a> {</div><div class="line"><a name="l00461"></a><span class="lineno"> 461</span>  <span class="keyword">template</span> <<span class="keyword">typename</span> Ch1, <span class="keyword">typename</span> Ch2></div><div class="line"><a name="l00462"></a><span class="lineno"> 462</span>  <span class="keywordtype">void</span> operator()(<span class="keyword">const</span> Ch1& src, Ch2& dst)<span class="keyword"> const </span>{</div><div class="line"><a name="l00463"></a><span class="lineno"> 463</span>  dst=channel_convert<Ch2>(src);</div><div class="line"><a name="l00464"></a><span class="lineno"> 464</span>  }</div><div class="line"><a name="l00465"></a><span class="lineno"> 465</span> };</div><div class="line"><a name="l00466"></a><span class="lineno"> 466</span> </div><div class="line"><a name="l00467"></a><span class="lineno"> 467</span> <span class="keyword">namespace </span>detail {</div><div class="line"><a name="l00468"></a><span class="lineno"> 468</span>  <span class="comment">// fast integer division by 255</span></div><div class="line"><a name="l00469"></a><span class="lineno"> 469</span>  <span class="keyword">inline</span> uint32_t div255(uint32_t in) { uint32_t tmp=in+128; <span class="keywordflow">return</span> (tmp + (tmp>>8))>>8; }</div><div class="line"><a name="l00470"></a><span class="lineno"> 470</span> </div><div class="line"><a name="l00471"></a><span class="lineno"> 471</span>  <span class="comment">// fast integer divison by 32768</span></div><div class="line"><a name="l00472"></a><span class="lineno"> 472</span>  <span class="keyword">inline</span> uint32_t div32768(uint32_t in) { <span class="keywordflow">return</span> (in+16384)>>15; }</div><div class="line"><a name="l00473"></a><span class="lineno"> 473</span> }</div><div class="line"><a name="l00474"></a><span class="lineno"> 474</span> </div><div class="line"><a name="l00487"></a><span class="lineno"> 487</span> </div><div class="line"><a name="l00489"></a><span class="lineno"> 489</span> <span class="keyword">template</span> <<span class="keyword">typename</span> ChannelValue></div><div class="line"><a name="l00490"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1channel__multiplier__unsigned.html"> 490</a></span> <span class="keyword">struct </span><a class="code" href="structboost_1_1gil_1_1channel__multiplier__unsigned.html">channel_multiplier_unsigned</a> {</div><div class="line"><a name="l00491"></a><span class="lineno"> 491</span>  <span class="keyword">using</span> first_argument_type = ChannelValue;</div><div class="line"><a name="l00492"></a><span class="lineno"> 492</span>  <span class="keyword">using</span> second_argument_type = ChannelValue;</div><div class="line"><a name="l00493"></a><span class="lineno"> 493</span>  <span class="keyword">using</span> result_type = ChannelValue;</div><div class="line"><a name="l00494"></a><span class="lineno"> 494</span>  ChannelValue operator()(ChannelValue a, ChannelValue b)<span class="keyword"> const </span>{</div><div class="line"><a name="l00495"></a><span class="lineno"> 495</span>  <span class="keywordflow">return</span> ChannelValue(<span class="keyword">static_cast<</span>typename base_channel_type<ChannelValue>::type<span class="keyword">></span>(a / <span class="keywordtype">double</span>(channel_traits<ChannelValue>::max_value()) * b));</div><div class="line"><a name="l00496"></a><span class="lineno"> 496</span>  }</div><div class="line"><a name="l00497"></a><span class="lineno"> 497</span> };</div><div class="line"><a name="l00498"></a><span class="lineno"> 498</span> </div><div class="line"><a name="l00500"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1channel__multiplier__unsigned_3_01uint8__t_01_4.html"> 500</a></span> <span class="keyword">template</span><> <span class="keyword">struct </span><a class="code" href="structboost_1_1gil_1_1channel__multiplier__unsigned.html">channel_multiplier_unsigned</a><uint8_t> {</div><div class="line"><a name="l00501"></a><span class="lineno"> 501</span>  <span class="keyword">using</span> first_argument_type = uint8_t;</div><div class="line"><a name="l00502"></a><span class="lineno"> 502</span>  <span class="keyword">using</span> second_argument_type = uint8_t;</div><div class="line"><a name="l00503"></a><span class="lineno"> 503</span>  <span class="keyword">using</span> result_type = uint8_t;</div><div class="line"><a name="l00504"></a><span class="lineno"> 504</span>  uint8_t operator()(uint8_t a, uint8_t b)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> uint8_t(detail::div255(uint32_t(a) * uint32_t(b))); }</div><div class="line"><a name="l00505"></a><span class="lineno"> 505</span> };</div><div class="line"><a name="l00506"></a><span class="lineno"> 506</span> </div><div class="line"><a name="l00508"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1channel__multiplier__unsigned_3_01uint16__t_01_4.html"> 508</a></span> <span class="keyword">template</span><> <span class="keyword">struct </span><a class="code" href="structboost_1_1gil_1_1channel__multiplier__unsigned.html">channel_multiplier_unsigned</a><uint16_t> {</div><div class="line"><a name="l00509"></a><span class="lineno"> 509</span>  <span class="keyword">using</span> first_argument_type = uint16_t;</div><div class="line"><a name="l00510"></a><span class="lineno"> 510</span>  <span class="keyword">using</span> second_argument_type = uint16_t;</div><div class="line"><a name="l00511"></a><span class="lineno"> 511</span>  <span class="keyword">using</span> result_type = uint16_t;</div><div class="line"><a name="l00512"></a><span class="lineno"> 512</span>  uint16_t operator()(uint16_t a, uint16_t b)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> uint16_t((uint32_t(a) * uint32_t(b))/65535); }</div><div class="line"><a name="l00513"></a><span class="lineno"> 513</span> };</div><div class="line"><a name="l00514"></a><span class="lineno"> 514</span> </div><div class="line"><a name="l00516"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1channel__multiplier__unsigned_3_01float32__t_01_4.html"> 516</a></span> <span class="keyword">template</span><> <span class="keyword">struct </span><a class="code" href="structboost_1_1gil_1_1channel__multiplier__unsigned.html">channel_multiplier_unsigned</a><<a class="code" href="group___channel_model.html#gaa70e2f51d4342cd54a28684f20c6135b">float32_t</a>> {</div><div class="line"><a name="l00517"></a><span class="lineno"> 517</span>  <span class="keyword">using</span> first_argument_type = <a class="code" href="group___channel_model.html#gaa70e2f51d4342cd54a28684f20c6135b">float32_t</a>;</div><div class="line"><a name="l00518"></a><span class="lineno"> 518</span>  <span class="keyword">using</span> second_argument_type = <a class="code" href="group___channel_model.html#gaa70e2f51d4342cd54a28684f20c6135b">float32_t</a>;</div><div class="line"><a name="l00519"></a><span class="lineno"> 519</span>  <span class="keyword">using</span> result_type = <a class="code" href="group___channel_model.html#gaa70e2f51d4342cd54a28684f20c6135b">float32_t</a>;</div><div class="line"><a name="l00520"></a><span class="lineno"> 520</span>  <a class="code" href="group___channel_model.html#gaa70e2f51d4342cd54a28684f20c6135b">float32_t</a> operator()(<a class="code" href="group___channel_model.html#gaa70e2f51d4342cd54a28684f20c6135b">float32_t</a> a, <a class="code" href="group___channel_model.html#gaa70e2f51d4342cd54a28684f20c6135b">float32_t</a> b)<span class="keyword"> const </span>{ <span class="keywordflow">return</span> a*b; }</div><div class="line"><a name="l00521"></a><span class="lineno"> 521</span> };</div><div class="line"><a name="l00522"></a><span class="lineno"> 522</span> </div><div class="line"><a name="l00524"></a><span class="lineno"> 524</span> <span class="keyword">template</span> <<span class="keyword">typename</span> ChannelValue></div><div class="line"><a name="l00525"></a><span class="lineno"><a class="line" href="structboost_1_1gil_1_1channel__multiplier.html"> 525</a></span> <span class="keyword">struct </span><a class="code" href="structboost_1_1gil_1_1channel__multiplier.html">channel_multiplier</a> {</div><div class="line"><a name="l00526"></a><span class="lineno"> 526</span>  <span class="keyword">using</span> first_argument_type = ChannelValue;</div><div class="line"><a name="l00527"></a><span class="lineno"> 527</span>  <span class="keyword">using</span> second_argument_type = ChannelValue;</div><div class="line"><a name="l00528"></a><span class="lineno"> 528</span>  <span class="keyword">using</span> result_type = ChannelValue;</div><div class="line"><a name="l00529"></a><span class="lineno"> 529</span>  ChannelValue operator()(ChannelValue a, ChannelValue b)<span class="keyword"> const </span>{</div><div class="line"><a name="l00530"></a><span class="lineno"> 530</span>  <span class="keyword">using</span> to_unsigned = detail::channel_convert_to_unsigned<ChannelValue>;</div><div class="line"><a name="l00531"></a><span class="lineno"> 531</span>  <span class="keyword">using</span> from_unsigned = detail::channel_convert_from_unsigned<ChannelValue>;</div><div class="line"><a name="l00532"></a><span class="lineno"> 532</span>  <span class="keyword">using</span> multiplier_unsigned = <a class="code" href="structboost_1_1gil_1_1channel__multiplier__unsigned.html">channel_multiplier_unsigned<typename to_unsigned::result_type></a>;</div><div class="line"><a name="l00533"></a><span class="lineno"> 533</span>  <span class="keywordflow">return</span> from_unsigned()(multiplier_unsigned()(to_unsigned()(a), to_unsigned()(b)));</div><div class="line"><a name="l00534"></a><span class="lineno"> 534</span>  }</div><div class="line"><a name="l00535"></a><span class="lineno"> 535</span> };</div><div class="line"><a name="l00536"></a><span class="lineno"> 536</span> </div><div class="line"><a name="l00538"></a><span class="lineno"> 538</span> <span class="keyword">template</span> <<span class="keyword">typename</span> Channel> <span class="comment">// Models ChannelConcept (could be a channel reference)</span></div><div class="line"><a name="l00539"></a><span class="lineno"><a class="line" href="group___channel_multiply_algorithm.html#ga0af81efbbb77846afe2570f242d2b974"> 539</a></span> <span class="keyword">inline</span> <span class="keyword">typename</span> channel_traits<Channel>::value_type <a class="code" href="group___channel_multiply_algorithm.html#ga0af81efbbb77846afe2570f242d2b974">channel_multiply</a>(Channel a, Channel b) {</div><div class="line"><a name="l00540"></a><span class="lineno"> 540</span>  <span class="keywordflow">return</span> <a class="code" href="structboost_1_1gil_1_1channel__multiplier.html">channel_multiplier<typename channel_traits<Channel>::value_type</a>>()(a,b);</div><div class="line"><a name="l00541"></a><span class="lineno"> 541</span> }</div><div class="line"><a name="l00543"></a><span class="lineno"> 543</span> </div><div class="line"><a name="l00555"></a><span class="lineno"> 555</span> </div><div class="line"><a name="l00558"></a><span class="lineno"> 558</span> <span class="keyword">template</span> <<span class="keyword">typename</span> Channel> <span class="comment">// Models ChannelConcept (could be a channel reference)</span></div><div class="line"><a name="l00559"></a><span class="lineno"><a class="line" href="group___channel_invert_algorithm.html#gabbbc7b27d9f61ff45cf5ea7ac21051f5"> 559</a></span> <span class="keyword">inline</span> <span class="keyword">typename</span> channel_traits<Channel>::value_type <a class="code" href="group___channel_invert_algorithm.html#gabbbc7b27d9f61ff45cf5ea7ac21051f5">channel_invert</a>(Channel x) {</div><div class="line"><a name="l00560"></a><span class="lineno"> 560</span> </div><div class="line"><a name="l00561"></a><span class="lineno"> 561</span>  <span class="keyword">using</span> base_t = <span class="keyword">typename</span> base_channel_type<Channel>::type;</div><div class="line"><a name="l00562"></a><span class="lineno"> 562</span>  <span class="keyword">using</span> promoted_t = <span class="keyword">typename</span> promote_integral<base_t>::type;</div><div class="line"><a name="l00563"></a><span class="lineno"> 563</span>  promoted_t <span class="keyword">const</span> promoted_x = x;</div><div class="line"><a name="l00564"></a><span class="lineno"> 564</span>  promoted_t <span class="keyword">const</span> promoted_max = channel_traits<Channel>::max_value();</div><div class="line"><a name="l00565"></a><span class="lineno"> 565</span>  promoted_t <span class="keyword">const</span> promoted_min = channel_traits<Channel>::min_value();</div><div class="line"><a name="l00566"></a><span class="lineno"> 566</span>  promoted_t <span class="keyword">const</span> promoted_inverted_x = promoted_max - promoted_x + promoted_min;</div><div class="line"><a name="l00567"></a><span class="lineno"> 567</span>  <span class="keyword">auto</span> <span class="keyword">const</span> inverted_x = static_cast<base_t>(promoted_inverted_x);</div><div class="line"><a name="l00568"></a><span class="lineno"> 568</span>  <span class="keywordflow">return</span> inverted_x;</div><div class="line"><a name="l00569"></a><span class="lineno"> 569</span> }</div><div class="line"><a name="l00570"></a><span class="lineno"> 570</span> </div><div class="line"><a name="l00571"></a><span class="lineno"> 571</span> } } <span class="comment">// namespace boost::gil</span></div><div class="line"><a name="l00572"></a><span class="lineno"> 572</span> </div><div class="line"><a name="l00573"></a><span class="lineno"> 573</span> <span class="preprocessor">#endif</span></div><div class="ttc" id="group___channel_invert_algorithm_html_gabbbc7b27d9f61ff45cf5ea7ac21051f5"><div class="ttname"><a href="group___channel_invert_algorithm.html#gabbbc7b27d9f61ff45cf5ea7ac21051f5">boost::gil::channel_invert</a></div><div class="ttdeci">channel_traits< Channel >::value_type channel_invert(Channel x)</div><div class="ttdoc">Default implementation. Provide overloads for performance.</div><div class="ttdef"><b>Definition:</b> channel_algorithm.hpp:559</div></div>
- <div class="ttc" id="group___channel_model_html_gaa70e2f51d4342cd54a28684f20c6135b"><div class="ttname"><a href="group___channel_model.html#gaa70e2f51d4342cd54a28684f20c6135b">boost::gil::float32_t</a></div><div class="ttdeci">scoped_channel_value< float, float_point_zero< float >, float_point_one< float > > float32_t</div><div class="ttdoc">32-bit floating point channel type with range [0.0f ... 1.0f]. Models ChannelValueConcept</div><div class="ttdef"><b>Definition:</b> typedefs.hpp:124</div></div>
- <div class="ttc" id="group___channel_convert_algorithm_html_ga1ca10b1d27bc2f2ce4906b8890e613a5"><div class="ttname"><a href="group___channel_convert_algorithm.html#ga1ca10b1d27bc2f2ce4906b8890e613a5">boost::gil::channel_convert</a></div><div class="ttdeci">channel_traits< DstChannel >::value_type channel_convert(const SrcChannel &src)</div><div class="ttdoc">Converting from one channel type to another.</div><div class="ttdef"><b>Definition:</b> channel_algorithm.hpp:451</div></div>
- <div class="ttc" id="group___channel_multiply_algorithm_html_ga0af81efbbb77846afe2570f242d2b974"><div class="ttname"><a href="group___channel_multiply_algorithm.html#ga0af81efbbb77846afe2570f242d2b974">boost::gil::channel_multiply</a></div><div class="ttdeci">channel_traits< Channel >::value_type channel_multiply(Channel a, Channel b)</div><div class="ttdoc">A function multiplying two channels. result = a * b / max_value.</div><div class="ttdef"><b>Definition:</b> channel_algorithm.hpp:539</div></div>
- <div class="ttc" id="structboost_1_1gil_1_1detail_1_1identity_html"><div class="ttname"><a href="structboost_1_1gil_1_1detail_1_1identity.html">boost::gil::detail::identity</a></div><div class="ttdoc">identity taken from SGI STL.</div><div class="ttdef"><b>Definition:</b> utilities.hpp:209</div></div>
- <div class="ttc" id="structboost_1_1gil_1_1default__channel__converter_html"><div class="ttname"><a href="structboost_1_1gil_1_1default__channel__converter.html">boost::gil::default_channel_converter</a></div><div class="ttdoc">Same as channel_converter, except it takes the destination channel by reference, which allows us to m...</div><div class="ttdef"><b>Definition:</b> channel_algorithm.hpp:460</div></div>
- <div class="ttc" id="structboost_1_1gil_1_1channel__multiplier_html"><div class="ttname"><a href="structboost_1_1gil_1_1channel__multiplier.html">boost::gil::channel_multiplier</a></div><div class="ttdoc">A function object to multiply two channels. result = a * b / max_value.</div><div class="ttdef"><b>Definition:</b> channel_algorithm.hpp:525</div></div>
- <div class="ttc" id="structboost_1_1gil_1_1channel__multiplier__unsigned_html"><div class="ttname"><a href="structboost_1_1gil_1_1channel__multiplier__unsigned.html">boost::gil::channel_multiplier_unsigned</a></div><div class="ttdoc">This is the default implementation. Performance specializatons are provided.</div><div class="ttdef"><b>Definition:</b> channel_algorithm.hpp:490</div></div>
- <div class="ttc" id="structboost_1_1gil_1_1detail_1_1channel__converter__unsigned__impl_html"><div class="ttname"><a href="structboost_1_1gil_1_1detail_1_1channel__converter__unsigned__impl.html">boost::gil::detail::channel_converter_unsigned_impl</a></div><div class="ttdoc">This is the default implementation. Performance specializatons are provided.</div><div class="ttdef"><b>Definition:</b> channel_algorithm.hpp:26</div></div>
- <div class="ttc" id="structboost_1_1gil_1_1channel__converter_html"><div class="ttname"><a href="structboost_1_1gil_1_1channel__converter.html">boost::gil::channel_converter</a></div><div class="ttdoc">A unary function object converting between channel types.</div><div class="ttdef"><b>Definition:</b> channel_algorithm.hpp:437</div></div>
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