(This is the documentation for SDL3, which is the current stable version. SDL2 was the previous version!)

SDL_BlitSurface

Performs a fast blit from the source surface to the destination surface.

Header File

Syntax

bool SDL_BlitSurface(SDL_Surface *src, const SDL_Rect *srcrect, SDL_Surface *dst, const SDL_Rect *dstrect);

Function Parameters

SDL_Surface *	src	the SDL_Surface structure to be copied from.
const SDL_Rect *	srcrect	the SDL_Rect structure representing the rectangle to be copied, or NULL to copy the entire surface.
SDL_Surface *	dst	the SDL_Surface structure that is the blit target.
const SDL_Rect *	dstrect	the SDL_Rect structure representing the x and y position in the destination surface, or NULL for (0,0). The width and height are ignored, and are copied from `srcrect`. If you want a specific width and height, you should use SDL_BlitSurfaceScaled().

Return Value

(bool) Returns true on success or false on failure; call SDL_GetError() for more information.

Remarks

This assumes that the source and destination rectangles are the same size. If either srcrect or dstrect are NULL, the entire surface (src or dst) is copied. The final blit rectangles are saved in srcrect and dstrect after all clipping is performed.

The blit function should not be called on a locked surface.

The blit semantics for surfaces with and without blending and colorkey are defined as follows:

   RGBA->RGB:
     Source surface blend mode set to SDL_BLENDMODE_BLEND:
      alpha-blend (using the source alpha-channel and per-surface alpha)
      SDL_SRCCOLORKEY ignored.
    Source surface blend mode set to SDL_BLENDMODE_NONE:
      copy RGB.
      if SDL_SRCCOLORKEY set, only copy the pixels that do not match the
      RGB values of the source color key, ignoring alpha in the
      comparison.

  RGB->RGBA:
    Source surface blend mode set to SDL_BLENDMODE_BLEND:
      alpha-blend (using the source per-surface alpha)
    Source surface blend mode set to SDL_BLENDMODE_NONE:
      copy RGB, set destination alpha to source per-surface alpha value.
    both:
      if SDL_SRCCOLORKEY set, only copy the pixels that do not match the
      source color key.

  RGBA->RGBA:
    Source surface blend mode set to SDL_BLENDMODE_BLEND:
      alpha-blend (using the source alpha-channel and per-surface alpha)
      SDL_SRCCOLORKEY ignored.
    Source surface blend mode set to SDL_BLENDMODE_NONE:
      copy all of RGBA to the destination.
      if SDL_SRCCOLORKEY set, only copy the pixels that do not match the
      RGB values of the source color key, ignoring alpha in the
      comparison.

  RGB->RGB:
    Source surface blend mode set to SDL_BLENDMODE_BLEND:
      alpha-blend (using the source per-surface alpha)
    Source surface blend mode set to SDL_BLENDMODE_NONE:
      copy RGB.
    both:
      if SDL_SRCCOLORKEY set, only copy the pixels that do not match the
      source color key.

Thread Safety

The same destination surface should not be used from two threads at once. It is safe to use the same source surface from multiple threads.

Version

This function is available since SDL 3.1.3.

Code Examples

SDL_Surface *surface;
SDL_Rect source_rect;
SDL_Surface *temp_surface;

SDL_BlitSurface(surface, &source_rect, temp_surface, NULL);