SDL_SetColors (3)

#include "SDL.h"

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

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

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_SetColors 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.

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_SetColors modifies both palettes (if present), and is equivalent to calling SDL_SetPalette with the flags set to (SDL_LOGPAL | SDL_PHYSPAL).

If surface is not a palettized surface, this function does nothing, returning 0. If all of the colors were set as passed to SDL_SetColors, 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.

/* Create a display surface with a grayscale palette */
SDL_Surface *screen;
SDL_Color colors[256];
int i;
.
.
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/* 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_SetColors(screen, colors, 0, 256);
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.
.
.

SDL_Color SDL_Surface, SDL_SetPalette, SDL_SetVideoMode