Provided by: libsdl3-doc_3.2.20+ds-2_all 

NAME
SDL_RenderReadPixels - Read pixels from the current rendering target.
SYNOPSIS
#include <SDL3/SDL_render.h>
SDL_Surface * SDL_RenderReadPixels(SDL_Renderer *renderer, const SDL_Rect *rect);
DESCRIPTION
The returned surface contains pixels inside the desired area clipped to the current viewport, and should
be freed with SDL_DestroySurface().
Note that this returns the actual pixels on the screen, so if you are using logical presentation you
should use SDL_GetRenderLogicalPresentationRect() to get the area containing your content.
WARNING: This is a very slow operation, and should not be used frequently. If you're using this on the
main rendering target, it should be called after rendering and before SDL_RenderPresent().
FUNCTION PARAMETERS
renderer
the rendering context.
rect an SDL_Rect structure representing the area to read, which will be clipped to the current
viewport, or NULL for the entire viewport.
RETURN VALUE
Returns a new SDL_Surface on success or NULL on failure; call SDL_GetError() for more information.
THREAD SAFETY
This function should only be called on the main thread.
AVAILABILITY
This function is available since SDL 3.2.0.
Simple Directmedia Layer SDL 3.2.20 SDL_RenderReadPixels(3)