Get the output size in pixels of a rendering context.
int SDL_GetRendererOutputSize(SDL_Renderer * renderer, int *w, int *h);
|renderer||the rendering context|
|w||an int filled with the width|
|h||an int filled with the height|
Returns 0 on success or a negative error code on failure; call SDL_GetError() for more information.
Due to high-dpi displays, you might end up with a rendering context that has more pixels than the window that contains it, so use this instead of SDL_GetWindowSize() to decide how much drawing area you have.
This function is available since SDL 2.0.0.