SDL_RenderReadPixels - Man Page

#include <SDL3/SDL_render.h>

SDL_Surface * SDL_RenderReadPixels(SDL_Renderer *renderer, const SDL_Rect *rect);

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().

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.

Returns a new SDL_Surface on success or NULL on failure; call SDL_GetError() for more information.

This function should only be called on the main thread.

This function is available since SDL 3.2.0.