docs/man3/SDL_SetPalette.3
author Sam Lantinga <slouken@libsdl.org>
Wed, 08 Mar 2006 18:30:12 +0000
changeset 1486 9d77fc9d0ace
parent 181 e5bc29de3f0a
child 2283 546f7c1eb755
permissions -rw-r--r--
Re-added C runtime support for Visual C++ 5,6
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.TH "SDL_SetPalette" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
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.SH "NAME"
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SDL_SetPalette\- Sets the colors in the palette of an 8-bit surface\&.
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.SH "SYNOPSIS"
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.PP
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\fB#include "SDL\&.h"
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.sp
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\fBint \fBSDL_SetPalette\fP\fR(\fBSDL_Surface *surface, int flags, SDL_Color *colors, int firstcolor, int ncolors\fR);
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.SH "DESCRIPTION"
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.PP
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Sets a portion of the palette for the given 8-bit surface\&.
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.PP
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Palettized (8-bit) screen surfaces with the \fBSDL_HWPALETTE\fP 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)\&. \fISDL_BlitSurface\fR 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)\&.
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.PP
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This function can modify either the logical or physical palette by specifing \fBSDL_LOGPAL\fP or \fBSDL_PHYSPAL\fPthe in the \fBflags\fR parameter\&.
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.PP
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When \fBsurface\fR is the surface associated with the current display, the display colormap will be updated with the requested colors\&. If \fBSDL_HWPALETTE\fP was set in \fISDL_SetVideoMode\fR flags, \fBSDL_SetPalette\fP will always return \fB1\fR, 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\&.
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.PP
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The color components of a \fI\fBSDL_Color\fR\fR structure are 8-bits in size, giving you a total of 256^3=16777216 colors\&.
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.SH "RETURN VALUE"
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.PP
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If \fBsurface\fR is not a palettized surface, this function does nothing, returning \fB0\fR\&. If all of the colors were set as passed to \fBSDL_SetPalette\fP, it will return \fB1\fR\&. If not all the color entries were set exactly as given, it will return \fB0\fR, and you should look at the surface palette to determine the actual color palette\&.
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.SH "EXAMPLE"
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.PP
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.nf
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\f(CW        /* Create a display surface with a grayscale palette */
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        SDL_Surface *screen;
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        SDL_Color colors[256];
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        int i;
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        \&.
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        \&.
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        \&.
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        /* Fill colors with color information */
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        for(i=0;i<256;i++){
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          colors[i]\&.r=i;
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          colors[i]\&.g=i;
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          colors[i]\&.b=i;
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        }
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        /* Create display */
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        screen=SDL_SetVideoMode(640, 480, 8, SDL_HWPALETTE);
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        if(!screen){
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          printf("Couldn\&'t set video mode: %s
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", SDL_GetError());
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          exit(-1);
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        }
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        /* Set palette */
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        SDL_SetPalette(screen, SDL_LOGPAL|SDL_PHYSPAL, colors, 0, 256);
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        \&.
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        \&.
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        \&.
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        \&.\fR
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.fi
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.PP
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.SH "SEE ALSO"
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.PP
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\fISDL_SetColors\fR, \fISDL_SetVideoMode\fR, \fISDL_Surface\fR, \fISDL_Color\fR
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...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01