view docs/man3/SDL_SetPalette.3 @ 1614:6162b8d921ce

Date: Wed, 29 Mar 2006 17:26:55 +0200 CEST From: "Fran���is Revol" Subject: [SDL] BeOS port fix: PrintScreen key crashing It seems the latest SDL crashes when someone hits the PrtScrn key in ZETA (BeOS R6), somewhere it gets a negative value as key code (or a big unsigned maybe ?), and uses it as an index in the keysym table... I'll investigate the cause for the negative value, but it's always better to check for bounds correctly when indexing a table. The attached diff fixes it. Fran���is Revol -- Software Architect yellowTAB GmbH
author Sam Lantinga <slouken@libsdl.org>
date Fri, 31 Mar 2006 06:16:20 +0000
parents e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_SetPalette" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_SetPalette\- Sets the colors in the palette of an 8-bit surface\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_SetPalette\fP\fR(\fBSDL_Surface *surface, int flags, SDL_Color *colors, int firstcolor, int ncolors\fR);
.SH "DESCRIPTION"
.PP
Sets a portion of the palette for the given 8-bit surface\&.
.PP
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)\&.
.PP
This function can modify either the logical or physical palette by specifing \fBSDL_LOGPAL\fP or \fBSDL_PHYSPAL\fPthe in the \fBflags\fR parameter\&.
.PP
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\&.
.PP
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\&.
.SH "RETURN VALUE"
.PP
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\&.
.SH "EXAMPLE"
.PP
.nf
\f(CW        /* 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);
        \&.
        \&.
        \&.
        \&.\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fISDL_SetColors\fR, \fISDL_SetVideoMode\fR, \fISDL_Surface\fR, \fISDL_Color\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01