Is Freetype needed for Gd? Or just truetype fonts?

Hello. What I mean is, I want to manipulate images that exist, and those that I create To use truetype fonts so the default font text is not all that's required, but more importantly I want to do all the stuff gd/php can do so, I wonder if *just* having true type font support is enough, or is freetype so special, I must get that with libpng/gd and the rest? IN order to make/modify images, text on those images specifically. I am just confused that's all Thanks for your time Joel