title: How to draw a NSImage like images in NSButtons (with a deepness)?
body: <p>Is there any way to draw an NSImage like images in NSButtons or other cocoa interface elements?</p>
  
  <p>Here are examples:
  <img src="https://i.stack.imgur.com/lrWpR.png" alt="enter image description here">
  <img src="https://i.stack.imgur.com/580vf.png" alt="enter image description here"></p>
  
  <p>Apple uses pdf's with black icons:
  <img src="https://i.stack.imgur.com/nYdK0.png" alt="enter image description here"></p>