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| ><H1 |
| ><A |
| NAME="SDLSETCOLORKEY" |
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| >SDL_SetColorKey</H1 |
| ><DIV |
| CLASS="REFNAMEDIV" |
| ><A |
| NAME="AEN2045" |
| ></A |
| ><H2 |
| >Name</H2 |
| >SDL_SetColorKey -- Sets the color key (transparent pixel) in a blittable surface and |
| RLE acceleration.</DIV |
| ><DIV |
| CLASS="REFSYNOPSISDIV" |
| ><A |
| NAME="AEN2048" |
| ></A |
| ><H2 |
| >Synopsis</H2 |
| ><DIV |
| CLASS="FUNCSYNOPSIS" |
| ><A |
| NAME="AEN2049" |
| ></A |
| ><P |
| ></P |
| ><PRE |
| CLASS="FUNCSYNOPSISINFO" |
| >#include "SDL.h"</PRE |
| ><P |
| ><CODE |
| ><CODE |
| CLASS="FUNCDEF" |
| >int <B |
| CLASS="FSFUNC" |
| >SDL_SetColorKey</B |
| ></CODE |
| >(SDL_Surface *surface, Uint32 flag, Uint32 key);</CODE |
| ></P |
| ><P |
| ></P |
| ></DIV |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN2055" |
| ></A |
| ><H2 |
| >Description</H2 |
| ><P |
| > Sets the color key (transparent pixel) in a blittable surface and enables or |
| disables RLE blit acceleration.</P |
| ><P |
| >RLE acceleration can substantially speed up blitting of images with large |
| horizontal runs of transparent pixels (i.e., pixels that match the |
| <TT |
| CLASS="PARAMETER" |
| ><I |
| >key</I |
| ></TT |
| > value). The <TT |
| CLASS="PARAMETER" |
| ><I |
| >key</I |
| ></TT |
| > must be of the same pixel format as the <TT |
| CLASS="PARAMETER" |
| ><I |
| >surface</I |
| ></TT |
| >, <A |
| HREF="sdlmaprgb.html" |
| ><TT |
| CLASS="FUNCTION" |
| >SDL_MapRGB</TT |
| ></A |
| > is often useful for obtaining an acceptable value.</P |
| ><P |
| >If <TT |
| CLASS="PARAMETER" |
| ><I |
| >flag</I |
| ></TT |
| > is <TT |
| CLASS="LITERAL" |
| >SDL_SRCCOLORKEY</TT |
| > then |
| <TT |
| CLASS="PARAMETER" |
| ><I |
| >key</I |
| ></TT |
| > is the transparent pixel value in the source image of a |
| blit.</P |
| ><P |
| >If <TT |
| CLASS="PARAMETER" |
| ><I |
| >flag</I |
| ></TT |
| > is OR'd with |
| <TT |
| CLASS="LITERAL" |
| >SDL_RLEACCEL</TT |
| > then the surface will be draw using RLE |
| acceleration when drawn with |
| <A |
| HREF="sdlblitsurface.html" |
| >SDL_BlitSurface</A |
| >. The surface will |
| actually be encoded for RLE acceleration the first time |
| <A |
| HREF="sdlblitsurface.html" |
| >SDL_BlitSurface</A |
| > or |
| <A |
| HREF="sdldisplayformat.html" |
| >SDL_DisplayFormat</A |
| > is called on the |
| surface.</P |
| ><P |
| >If <TT |
| CLASS="PARAMETER" |
| ><I |
| >flag</I |
| ></TT |
| > is 0, this function clears |
| any current color key.</P |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN2076" |
| ></A |
| ><H2 |
| >Return Value</H2 |
| ><P |
| >This function returns <SPAN |
| CLASS="RETURNVALUE" |
| >0</SPAN |
| >, or |
| <SPAN |
| CLASS="RETURNVALUE" |
| >-1</SPAN |
| > if there was an error.</P |
| ></DIV |
| ><DIV |
| CLASS="REFSECT1" |
| ><A |
| NAME="AEN2081" |
| ></A |
| ><H2 |
| >See Also</H2 |
| ><P |
| ><A |
| HREF="sdlblitsurface.html" |
| ><TT |
| CLASS="FUNCTION" |
| >SDL_BlitSurface</TT |
| ></A |
| >, |
| <A |
| HREF="sdldisplayformat.html" |
| ><TT |
| CLASS="FUNCTION" |
| >SDL_DisplayFormat</TT |
| ></A |
| >, |
| <A |
| HREF="sdlmaprgb.html" |
| ><TT |
| CLASS="FUNCTION" |
| >SDL_MapRGB</TT |
| ></A |
| >, |
| <A |
| HREF="sdlsetalpha.html" |
| ><TT |
| CLASS="FUNCTION" |
| >SDL_SetAlpha</TT |
| ></A |
| ></P |
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