an>&#160;<span class="keyword">auto</span> alpha_or_max_impl(Pixel <span class="keyword">const</span>&amp; p, std::true_type) -&gt; <span class="keyword">typename</span> <a class="code" href="structboost_1_1gil_1_1channel__type.html">channel_type&lt;Pixel&gt;::type</a></div><div class="line"><a name="l00250"></a><span class="lineno">  250</span>&#160;{</div><div class="line"><a name="l00251"></a><span class="lineno">  251</span>&#160;    <span class="keywordflow">return</span> <a class="code" href="group___