No, it is not a subset, unless you are talking about drawing textures. Those libraries use GPU rendering using textures, like distance fields(Qt) or simply cal

No, it is not a subset, unless you are talking about drawing textures. Those libraries use GPU rendering using textures, like distance fields(Qt) or simply calculate fonts in 2D and draw it on textures using the GPU, like Apple or cairo usually do. Distance fields are blurry when you have small fonts on display. Things like calculating the exact area order the 2D curve is something you could easily do in CPU, but it is extremely difficult to do on the GPU. You need decoupled data in order to parallelize it.