title: Lower Left Coordinates of SKScene
body: <p>I'm new to Swift SpriteKit programming and the coordinate system is driving me crazy.  I create a sprite and I want to move it to the four corners of the screen.  So, I set the position to (0,0).  That's off the bottom left corner of the screen.  Through some manual testing I've developed the chart below.  The lower left and upper right are what the iOS simulator report when I touch the screen.</p>
  
  <p>I have 2 questions:</p>
  
  <p>1: Is there a method of determining the coordinates of the lower left hand corner of the view?  Maybe I could build a dictionary with the coordinate values and the determine the machine type and then set the offsets.  But, that's a lot of work and might not be accurate for new devices.  It just seems that there should be a scene or frame property that I can use to put an object at the bottom left of the window.</p>
  
  <p>2:  The math doesn't work.  In the iPhone5, 300 (lower left x) + 320 (width) = 620, not the reported 727.  Same issue is true with the y coordinates.  How does this work?</p>
  
  <p>I set as few parameters as possible.  I have not changed the anchorPoint or position of the scene.</p>
  
  <pre>
  Device      Size            LL      UR
  iPhone4s    (320,480)   (260,0) (766,764)
  iPhone5     (320,568)   (300,0) (727,764)
  iPhone5s    (320,568)   (298,0) (727,764)
  iPhone6     (375,667)   (297,1) (728,765)
  iPhone6plus (414,736)   (298,0) (728,766)
  iPad2       (768,1024)  (226,0) (800,768)
  iPad Air    (768,1024)  (224,0) (800,767)
  iPad Retina (768,1024)  (225,0) (800,768)
  </pre>