Perhaps I was looking at something outdated. As for rotation, that was because SDL_gfx modifies the pixels of the surface itself, using trigonometry and all of that. SMFL, relying on OpenGL, maps loaded graphics to 3D surfaces, which can easily be rotated (so the renderer handles the rotation instead of the actual image data having to be modified to perform a rotation).
Whenever I feel like it, I may install SMFL and write a simple program in it and write an SDL version of it and compare things like file-size, how much memory is used by each one, and the like. There are just so many graphical libraries out there, each with their ups and downs. Thanks again, and have a great day!
I would like to also provide a link to a video I found pertaining to this subject:
What he says about SDL being the most low-level, how it is the API of choice for working on a low level, it being C-based, and all of that... those things and more are the reasons I prefer SDL.
This topic has kind of strayed. LOL.