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| >SDL_DisplayFormatAlpha</H1 |
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| NAME="AEN2432" |
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| ><H2 |
| >Name</H2 |
| >SDL_DisplayFormatAlpha -- Convert a surface to the display format</DIV |
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| NAME="AEN2435" |
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| >Synopsis</H2 |
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| ><PRE |
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| >#include "SDL.h"</PRE |
| ><P |
| ><CODE |
| ><CODE |
| CLASS="FUNCDEF" |
| >SDL_Surface *<B |
| CLASS="FSFUNC" |
| >SDL_DisplayFormatAlpha</B |
| ></CODE |
| >(SDL_Surface *surface);</CODE |
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| ><H2 |
| >Description</H2 |
| ><P |
| >This function takes a surface and copies it to a new surface of the |
| pixel format and colors of the video framebuffer plus an alpha channel, |
| suitable for fast blitting onto the display surface. It calls |
| <A |
| HREF="sdlconvertsurface.html" |
| >SDL_ConvertSurface</A |
| ></P |
| ><P |
| >If you want to take advantage of hardware colorkey or alpha blit |
| acceleration, you should set the colorkey and alpha value before |
| calling this function.</P |
| ><P |
| >This function can be used to convert a colourkey to an alpha channel, |
| if the <TT |
| CLASS="LITERAL" |
| >SDL_SRCCOLORKEY</TT |
| > flag is set on the surface. |
| The generated surface will then be transparent (alpha=0) where the |
| pixels match the colourkey, and opaque (alpha=255) elsewhere.</P |
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| CLASS="REFSECT1" |
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| NAME="AEN2449" |
| ></A |
| ><H2 |
| >Return Value</H2 |
| ><P |
| >If the conversion fails or runs out of memory, it returns |
| <SPAN |
| CLASS="RETURNVALUE" |
| >NULL</SPAN |
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| ></A |
| ><H2 |
| >See Also</H2 |
| ><P |
| ><A |
| HREF="sdlconvertsurface.html" |
| >SDL_ConvertSurface</A |
| >, |
| <A |
| HREF="sdlsetalpha.html" |
| >SDL_SetAlpha</A |
| >, |
| <A |
| HREF="sdlsetcolorkey.html" |
| >SDL_SetColorKey</A |
| >, |
| <A |
| HREF="sdldisplayformat.html" |
| >SDL_DisplayFormat</A |
| >, |
| <A |
| HREF="sdlsurface.html" |
| >SDL_Surface</A |
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