Tao.Sdl SDK Documentation

Sdl.SDL_SetPalette Method 

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

[Visual Basic]
Public Shared Function SDL_SetPalette( _
   ByVal surface As IntPtr, _
   ByVal flags As Integer, _
   ByVal colors As SDL_Color(), _
   ByVal firstcolor As Integer, _
   ByVal ncolors As Integer _
) As Integer
[C#]
public static int SDL_SetPalette(
   IntPtr surface,
   int flags,
   SDL_Color[] colors,
   int firstcolor,
   int ncolors
);

Parameters

surface
flags
colors
firstcolor
ncolors

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.

Remarks

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 2563=16777216 colors.

'flags' is one or both of: SDL_LOGPAL -- set logical palette, which controls how blits are mapped to/from the surface, SDL_PHYSPAL -- set physical palette, which controls how pixels look on the screen Only screens have physical palettes. Separate change of physical/logical palettes is only possible if the screen has SDL_HWPALETTE set.

SDL_SetColors() is equivalent to calling this function with flags = (SDL_LOGPAL|SDL_PHYSPAL).

Binds to C-function call in SDL_video.h:

extern DECLSPEC int SDLCALL SDL_SetPalette(SDL_Surface *surface, int flags, SDL_Color *colors, int firstcolor, int ncolors)

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\n", SDL_GetError());
                exit(-1);
            }
                /* Set palette */
                SDL_SetPalette(screen, SDL_LOGPAL|SDL_PHYSPAL, colors, 0, 256);
                .
                .
                .
                .

See Also

Sdl Class | Tao.Sdl Namespace