as well for Scalars.</p>

<h2 id="A.-Compose-hidden-image-with-PDL">A. Compose hidden image with PDL</h2>

<p>With PDL a whole Matrix can be Shifted and ORed at once. This is done in one single line.</p>

<pre><code> my %hidden;
 @hidden{ &#39;bit7&#39;,&#39;bit6&#39;,&#39;bit5&#39; } = (
        $image{bit_plane}{red}[0],
        $image{bit_plane}{green}[0],
        $image{bit_plane}{blue}[0],
 );
 $hidden{data} = ($hidden{bit7} &lt;&lt; 7) | ($hidden{bit6} &lt;&lt; 6) | ($hidden{bit5} &lt;&lt; 5);</code><