Function fermium::surface::SDL_BlitSurface

pub unsafe extern "C" fn SDL_BlitSurface(
    src: *mut SDL_Surface,
    srcrect: *const SDL_Rect,
    dst: *mut SDL_Surface,
    dstrect: *mut SDL_Rect
) -> c_int

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

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.

Return: If the blit is successful, it returns 0, otherwise it returns -1.

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 matching 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 matching 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 matching 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 matching the
    source color key.

You should call SDL_BlitSurface unless you know exactly how SDL blitting works internally and how to use the other blit functions.