Proposal: Vector graphics API

SDL Development
1

Vector graphics are a great utility for developers, which SDL2 supports but partially(with functions like SDL_RenderDrawRect and SDL_RenderFillRect). Developers can use SDL2_gfx, but it uses pixel plotting (as noted by @rtrussell) to draw the shapes, which may be a bit inefficient. Another alternative is to use OpenGL/DirectX/Vulcan/Metal vector graphics libraries, but this solution requires the developer to handle cross-platform stuff (when using DirectX/Metal). On the other hand, SDL2 handles cross-platform API-s by choosing the most performant one.
So I propose to (only one of these ideas, choice goes to the developers of SDL2):

  1. add a new SDL2 “extension” library called SDL_Vgfx (if you think you find a better name, please suggest it)
  2. introduce a new header file on the library (I propose SDL_vg.h)
  3. add new drawing functions on the already existing SDL_render.h header
    which contain new drawing functions like SDL_RenderDrawCircle, SDL_RenderDrawEllipse, SDL_RenderDrawBezier, etc.

The functions I propose are similar to those provided by SDL2_gfx, with the exception that the proposed functions should use better drawing algorithms (other than pixel plotting) where possible to gain performance. I propose that anti-aliasing should be a must for each of these drawing functions (where needed, of course).

Suggestions are welcome. Thank you for your time.

2

I’m unsure what you mean by “software rendering” in this context. SDL2_gfx (and my own extensions) ultimately call SDL_RenderDrawPoints() or SDL_RenderDrawLine() so they do, indirectly, benefit from accelerated hardware rendering, if enabled.

Having to decompose everything to points and lines adds a bottleneck, certainly, but I wouldn’t describe it as “software rendering”.

3

Thanks for the note @rtrussell. With software rendering, I meant exactly what you said, but I just mixed using points/lines with software rendering. I fixed it now. Thanks once more.