[yairchu]

It is using OpenGL indirectly via the graphics-drawingcombinators library (http://hackage.haskell.org/package/graphics-drawingcombinato...).

Indeed the fonts may not be as pretty as with Cairo etc but on the other hand there are very nice animations when edits make stuff move around.

[seanmcdirmid]

Ah! I hand rolled my own code editor using WPF (mostly canvas and font rendering) for my live programming work. Its amazing what can be done when not using inflexible high level components.