ring:</p>
<pre class="highlight swift"><code><span class="k">let</span> <span class="nv">context</span> <span class="o">=</span> <span class="kt">NSGraphicsContext</span><span class="o">.</span><span class="nf">current</span><span class="p">()?</span><span class="o">.</span><span class="n">cgContext</span>
<span class="n">context</span><span class="p">?</span><span class="o">.</span><span class="nf">saveGState</span><span class="p">()</span>
<span class="n">context</span><span class="p">?</span><span class=