Get device independent resolution for rendering.
void SDL_RenderGetLogicalSize(SDL_Renderer * renderer, int *w, int *h);
|renderer||a rendering context|
|w||an int to be filled with the width|
|h||an int to be filled with the height|
When using the main rendering target (eg no target texture is set): this may return 0 for
h if the SDL_Renderer has never had its logical size set by SDL_RenderSetLogicalSize(). Otherwise it returns the logical width and height.
When using a target texture: Never return 0 for
h at first. Then it returns the logical width and height that are set.
This function is available since SDL 2.0.0.