s="highlight"><pre><span class="n">loc</span><span class="o">=</span><span class="n">img</span><span class="p">.</span><span class="n">xy_at</span><span class="p">(</span><span class="mi">10</span><span class="p">,</span><span class="mi">10</span><span class="p">);</span>            <span class="c1">// start at pixel (x=10,y=10)</span>
<span class="n">above</span><span class="o">=</span><span class="n">loc</span><span class="p">.</span><span class="n">cache_location</span><span class="p">(</span><span class