title: In what contexts is the coordinate space on iOS the (unflipped) default?
body: <p>According to the <a href="https://developer.apple.com/reference/coregraphics/cgrect" rel="nofollow noreferrer">documentation for CGRect</a></p>
  
  <blockquote>
    <p>In the default Core Graphics coordinate space, the origin is located
    in the lower-left corner of the rectangle and the rectangle extends
    towards the upper-right corner. If the context has a
    flipped-coordinate space—often the case on iOS—the origin is in the
    upper-left corner and the rectangle extends towards the lower-right
    corner.</p>
  </blockquote>
  
  <p>I've always taken it at face value that the coordinate system on iOS starts on the upper-left, but after reading this, it makes sense that it's flipped, and not the default coordinate space. You don't think about points on a Cartesian graph the same way you do on iOS, where adding to the Y value shifts down, not up.</p>
  
  <p>The documentation says it's 'often the case', so when is it not the case on iOS? And on what platforms is the coordinate space the Core Graphics default?</p>