title: Swift - Auto layout - UIView - Intrinsic Size Confusion
body: <p>When using auto layout, I am confused on how to set the size of both my view and, more importantly, my labels/buttons/images.</p>
  
  <p>I have read dozens of webpages perspectives. Many say that if I am using auto layout correctly, I should not need to explicitly state the size of my view objects. Yet, auto layout seems to almost demand exactly that, explicit size constraints! If I do not give them, auto layout says my image and view sizes are "ambiguous".</p>
  
  <p>I would also like to know what auto layout will do when my conatraints are loaded on a retina display. Will my 300x90 image suddenly be half the size? Will a view I pin 70 from the top now be covered by a navigation bar? Most auto layout tutorials focus on how to use constraints, not how my 300x90 image will be manipulated by the iOS on different devices.</p>
  
  <p>It seems like, if they wanted the view to be fluid then I should be specifying percents, not specific pixel measurements!</p>
  
  <p>Can anyone help me better understand how my views will scale up and down?</p>