itle="Default implementation. Provide overloads for performance.">channel_invert</a>(
<a name="l00215"></a>00215                        detail::rgb_to_luminance&lt;<span class="keyword">typename</span> <a class="code" href="g_i_l_0444.html" title="Specifies the type of the element associated with a given color tag.">color_element_type&lt;P1,black_t&gt;::type</a>&gt;(
<a name="l00216"></a>00216                             <a class="code" href="g_i_l_0106.html#g4b9fe0ec8239047ac50842800de872b9" title="Constan