title: Does CGPathAddArc include the center pixel of a circle?
body: <p>I use <code>CGPathAddArc</code> to create a circle, if the radius is 5 pixel, will the whole circle end up with 10 pixels width or 11 pixels? </p>
  
  <p>It's also confusing if it does end up with 10 pixels. In that case, what does it mean that center of a radius?</p>
  
  <p>The <code>CGPathAddArc</code> defined here:</p>
  
  <pre><code>void CGPathAddArc (
  CGMutablePathRef path,
  const CGAffineTransform *m,
  CGFloat x,
  CGFloat y,
  CGFloat radius,
  CGFloat startAngle,
  CGFloat endAngle,
  bool clockwise
  );
  </code></pre>