bionic (3) SDL_SetPalette.3.gz

NAME

       SDL_SetPalette - Sets the colors in the palette of an 8-bit surface.

SYNOPSIS

       #include "SDL.h"

       int SDL_SetPalette(SDL_Surface *surface, int flags, SDL_Color *colors, int firstcolor, int ncolors);

DESCRIPTION

       Sets a portion of the palette for the given 8-bit surface.

       Palettized  (8-bit) screen surfaces with the SDL_HWPALETTE flag have two palettes, a logical palette that
       is used for mapping blits to/from the surface and a physical palette (that determines  how  the  hardware
       will  map  the  colors  to  the  display).  SDL_BlitSurface always uses the logical palette when blitting
       surfaces (if it has to convert between surface pixel formats). Because of this, it  is  often  useful  to
       modify only one or the other palette to achieve various special color effects (e.g., screen fading, color
       flashes, screen dimming).

       This function can modify either the logical or physical palette by specifing SDL_LOGPAL or SDL_PHYSPALthe
       in the flags parameter.

       When  surface  is  the  surface associated with the current display, the display colormap will be updated
       with the requested colors. If SDL_HWPALETTE was set in SDL_SetVideoMode flags, SDL_SetPalette will always
       return  1, and the palette is guaranteed to be set the way you desire, even if the window colormap has to
       be warped or run under emulation.

       The color components of a SDL_Color structure are 8-bits in size, giving you a  total  of  256^3=16777216
       colors.

RETURN VALUE

       If  surface  is  not  a palettized surface, this function does nothing, returning 0. If all of the colors
       were set as passed to SDL_SetPalette, it will return 1. If not all the color entries were set exactly  as
       given,  it  will  return  0,  and  you  should  look at the surface palette to determine the actual color
       palette.

EXAMPLE

               /* Create a display surface with a grayscale palette */
               SDL_Surface *screen;
               SDL_Color colors[256];
               int i;
               .
               .
               .
               /* Fill colors with color information */
               for(i=0;i<256;i++){
                 colors[i].r=i;
                 colors[i].g=i;
                 colors[i].b=i;
               }

               /* Create display */
               screen=SDL_SetVideoMode(640, 480, 8, SDL_HWPALETTE);
               if(!screen){
                 printf("Couldn't set video mode: %s
       ", SDL_GetError());
                 exit(-1);
               }

               /* Set palette */
               SDL_SetPalette(screen, SDL_LOGPAL|SDL_PHYSPAL, colors, 0, 256);
               .
               .
               .
               .

SEE ALSO

       SDL_SetColors, SDL_SetVideoMode, SDL_Surface, SDL_Color