title: Display a color from a position on a gradient
body: <p>Using the Kinect, I'm taking height measurements of both hands from a table, and displaying a color on the screen that's determined by the proportion of the heights. For example, if handProportion = .5, the screen would be green. At any other proportion, the screen is red. However, I need green to transition smoothly into red.</p>
  
  <p>My first instinct is color bitshifting, but that sounds complicated. How can I write a function that displays a color from a gradient based on a position value in that gradient?</p>
  
  <p>Thank you!</p>