Manual Pages for UNIX Operating System command usage for man SDL_BlitSurface

SDL API Reference                              SDL_BlitSurface(3)



NAME
     SDL_BlitSurface - This performs a fast blit from the  source
     surface to the destination surface.

SYNOPSIS
     #include "SDL.h"

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

DESCRIPTION
     This performs a fast blit from the  source  surface  to  the
     destination surface.

     Only the position is used in  the  dstrect  (the  width  and
     height are ignored).

     If either srcrect or dstrect are NULL,  the  entire  surface
     (src or dst) is copied.

     The final blit rectangle is saved in dstrect after all clip-
     ping is performed (srcrect is not modified).

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

     The results of blitting operations vary greatly depending on
     whether  SDL_SRCAPLHA is set or not. See SDL_SetAlpha for an
     explaination of how this affects your  results.  Colorkeying
     and alpha attributes also interact with surface blitting, as
     the following pseudo-code should hopefully explain.

     if (source surface has SDL_SRCALPHA set) {
         if (source surface has alpha channel (that is, format->Amask != 0))
             blit using per-pixel alpha, ignoring any colour key
         else {
             if (source surface has SDL_SRCCOLORKEY set)
                 blit using the colour key AND the per-surface alpha value
             else
                 blit using the per-surface alpha value
         }
     } else {
         if (source surface has SDL_SRCCOLORKEY set)
             blit using the colour key
         else
             ordinary opaque rectangular blit
     }

RETURN VALUE
     If the blit  is  successful,  it  returns  0,  otherwise  it
     returns -1.





SDL            Last change: Tue 11 Sep 2001, 23:01              1






SDL API Reference                              SDL_BlitSurface(3)



     If either of the surfaces were in video memory, and the blit
     returns  -2,  the  video  memory  was  lost, so it should be
     reloaded with artwork and re-blitted:

             while ( SDL_BlitSurface(image, imgrect, screen, dstrect) == -2 ) {
                     while ( SDL_LockSurface(image)) < 0 )
                             Sleep(10);
                     -- Write image pixels to image->pixels --
                     SDL_UnlockSurface(image);
             }

      This happens under DirectX 5.0  when  the  system  switches
     away  from  your fullscreen application. Locking the surface
     will also fail until you have access  to  the  video  memory
     again.

SEE ALSO
     SDL_LockSurface, SDL_FillRect, SDL_Surface, SDL_Rect





































SDL            Last change: Tue 11 Sep 2001, 23:01              2