4.html">  128</a></span>&#160;<span class="keyword">struct </span><a class="code" href="structboost_1_1gil_1_1default__color__converter__impl.html">default_color_converter_impl</a>&lt;rgb_t,gray_t&gt; {</div><div class="line"><a name="l00129"></a><span class="lineno">  129</span>&#160;    <span class="keyword">template</span> &lt;<span class="keyword">typename</span> P1, <span class="keyword">typename</span> P2&gt;</div><div class="line"><a name="l00130"></a><span class="lineno">  130</span>&#160;    <span 