ss="lineno">  165</span> </div>
<div class="line"><a id="l00166" name="l00166"></a><span class="lineno">  166</span><span class="comment">// viewer traits</span></div>
<div class="line"><a id="l00167" name="l00167"></a><span class="lineno">  167</span><span class="keyword">template</span> &lt;<span class="keyword">typename</span> T&gt;</div>
<div class="foldopen" id="foldopen00168" data-start="{" data-end="};">
<div class="line"><a id="l00168" name="l00168"></a><span class="lineno"><a class="line" href="str