title: Draw ellipse gradient in Swift
body: <p>I want to draw ellipse gradient in Swift.</p>
  
  <p>In CSS: </p>
  
  <pre><code>background: radial-gradient(50% 25% at 20% 30%, #ffffff, #ff0000);
  </code></pre>
  
  <p>I expect appearance to be like following: </p>
  
  <p><a href="https://i.stack.imgur.com/38w9A.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/38w9A.png" alt="enter image description here"></a></p>
  
  <p>I know I can draw circle gradient by using <code>CGContext.drawRadialGradient(_:startCenter:startRadius:endCenter:endRadius:options)</code>.
  But, I don't know how to draw <strong>ellipse</strong> gradient.</p>
  
  <p>Any idea? Thanks in advance.</p>