Mercurial > sdl-ios-xcode

<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&nbsp;--&nbsp;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
>
author	Sam Lantinga <slouken@libsdl.org>
date	Thu, 01 Jan 2009 21:34:22 +0000
parents	355632dca928
children