eyword">using</span> gray_alpha64f_pixel_t = pixel&lt;double, gray_alpha_layout_t&gt;;</div><div class="line"><a name="l00059"></a><span class="lineno">   59</span>&#160;<span class="preprocessor">#endif // BOOST_GIL_IO_ENABLE_GRAY_ALPHA</span></div><div class="line"><a name="l00060"></a><span class="lineno">   60</span>&#160;</div><div class="line"><a name="l00061"></a><span class="lineno">   61</span>&#160;<span class="keyword">using</span> rgb64f_pixel_t = pixel&lt;double, rgb_layout_t&gt;;</div><div cla