Isn't cairo a vector font rendering system? DeFessler: if you would like to finish a game instead of prototype it for ages I'd kindly recommend Unity 3D With C++ you will focuns only on the mechanics/features not on the game in 99% of time. And there is a great probability it will never get done. With Unity you will have your game finished in notime but also get richer for the experience that a coder is not a game producer because you will run out on levers or excitement.
Did you try SDL or Alegro and the other stuff? I wish you all of luck in your project.