3 }
<a name="l00234"></a>00234 } <span class="comment">// namespace detail</span>
<a name="l00235"></a>00235 
<a name="l00236"></a>00236 <span class="comment">// Returns max_value if the pixel has no alpha channel. Otherwise returns the alpha.</span>
<a name="l00237"></a>00237 <span class="keyword">template</span> &lt;<span class="keyword">typename</span> Pixel&gt; 
<a name="l00238"></a>00238 <span class="keyword">typename</span> channel_type&lt;Pixel&gt;::type alpha_or_max(<span class="keyword">const</span