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view docs/html/sdldisplayformatalpha.html @ 4159:a1b03ba2fcd0 SDL-1.2
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author | Sam Lantinga <slouken@libsdl.org> |
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date | Mon, 08 Dec 2008 00:25:42 +0000 |
parents | 355632dca928 |
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<HTML ><HEAD ><TITLE >SDL_DisplayFormatAlpha</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Video" HREF="video.html"><LINK REL="PREVIOUS" TITLE="SDL_DisplayFormat" HREF="sdldisplayformat.html"><LINK REL="NEXT" TITLE="SDL_WarpMouse" HREF="sdlwarpmouse.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdldisplayformat.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlwarpmouse.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLDISPLAYFORMATALPHA" ></A >SDL_DisplayFormatAlpha</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN2432" ></A ><H2 >Name</H2 >SDL_DisplayFormatAlpha -- Convert a surface to the display format</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN2435" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN2436" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >SDL_Surface *<B CLASS="FSFUNC" >SDL_DisplayFormatAlpha</B ></CODE >(SDL_Surface *surface);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2442" ></A ><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 ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2449" ></A ><H2 >Return Value</H2 ><P >If the conversion fails or runs out of memory, it returns <SPAN CLASS="RETURNVALUE" >NULL</SPAN ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2453" ></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 ></P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdldisplayformat.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlwarpmouse.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_DisplayFormat</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="video.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_WarpMouse</TD ></TR ></TABLE ></DIV ></BODY ></HTML >