OpenTK: Detect display's DPI

Question

I want to use different scaling for my game if it's running on a Retina display. How do I detect display's DPI with OpenTK/C#?

Answer 1

I found a solution for differentiating between Retina and normal scale on the following page: https://github.com/opentk/opentk/issues/47

Scale factor is calculated with the following code and returns 1 for non-retina and 2 for Retina (at least in OS X):

// game is derived from GameWindow and screenSize
// is given as a parameter for its constructor.
var scale = game.Width / (float)screenSize.X;