symbian-qemu-0.9.1-12/libsdl-trunk/docs/html/sdldisplayformatalpha.html
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     4 >SDL_DisplayFormatAlpha</TITLE
       
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    40 >SDL Library Documentation</TH
       
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    71 ><H1
       
    72 ><A
       
    73 NAME="SDLDISPLAYFORMATALPHA"
       
    74 ></A
       
    75 >SDL_DisplayFormatAlpha</H1
       
    76 ><DIV
       
    77 CLASS="REFNAMEDIV"
       
    78 ><A
       
    79 NAME="AEN2432"
       
    80 ></A
       
    81 ><H2
       
    82 >Name</H2
       
    83 >SDL_DisplayFormatAlpha&nbsp;--&nbsp;Convert a surface to the display format</DIV
       
    84 ><DIV
       
    85 CLASS="REFSYNOPSISDIV"
       
    86 ><A
       
    87 NAME="AEN2435"
       
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    89 ><H2
       
    90 >Synopsis</H2
       
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    92 CLASS="FUNCSYNOPSIS"
       
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    94 NAME="AEN2436"
       
    95 ></A
       
    96 ><P
       
    97 ></P
       
    98 ><PRE
       
    99 CLASS="FUNCSYNOPSISINFO"
       
   100 >#include "SDL.h"</PRE
       
   101 ><P
       
   102 ><CODE
       
   103 ><CODE
       
   104 CLASS="FUNCDEF"
       
   105 >SDL_Surface *<B
       
   106 CLASS="FSFUNC"
       
   107 >SDL_DisplayFormatAlpha</B
       
   108 ></CODE
       
   109 >(SDL_Surface *surface);</CODE
       
   110 ></P
       
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   118 NAME="AEN2442"
       
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   120 ><H2
       
   121 >Description</H2
       
   122 ><P
       
   123 >This function takes a surface and copies it to a new surface of the
       
   124 pixel format and colors of the video framebuffer plus an alpha channel,
       
   125 suitable for fast blitting onto the display surface.  It calls
       
   126 <A
       
   127 HREF="sdlconvertsurface.html"
       
   128 >SDL_ConvertSurface</A
       
   129 ></P
       
   130 ><P
       
   131 >If you want to take advantage of hardware colorkey or alpha blit
       
   132 acceleration, you should set the colorkey and alpha value before
       
   133 calling this function.</P
       
   134 ><P
       
   135 >This function can be used to convert a colourkey to an alpha channel,
       
   136 if the <TT
       
   137 CLASS="LITERAL"
       
   138 >SDL_SRCCOLORKEY</TT
       
   139 > flag is set on the surface.
       
   140 The generated surface will then be transparent (alpha=0) where the
       
   141 pixels match the colourkey, and opaque (alpha=255) elsewhere.</P
       
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   144 CLASS="REFSECT1"
       
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   146 NAME="AEN2449"
       
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   148 ><H2
       
   149 >Return Value</H2
       
   150 ><P
       
   151 >If the conversion fails or runs out of memory, it returns
       
   152 <SPAN
       
   153 CLASS="RETURNVALUE"
       
   154 >NULL</SPAN
       
   155 ></P
       
   156 ></DIV
       
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   158 CLASS="REFSECT1"
       
   159 ><A
       
   160 NAME="AEN2453"
       
   161 ></A
       
   162 ><H2
       
   163 >See Also</H2
       
   164 ><P
       
   165 ><A
       
   166 HREF="sdlconvertsurface.html"
       
   167 >SDL_ConvertSurface</A
       
   168 >,
       
   169 <A
       
   170 HREF="sdlsetalpha.html"
       
   171 >SDL_SetAlpha</A
       
   172 >,
       
   173 <A
       
   174 HREF="sdlsetcolorkey.html"
       
   175 >SDL_SetColorKey</A
       
   176 >,
       
   177 <A
       
   178 HREF="sdldisplayformat.html"
       
   179 >SDL_DisplayFormat</A
       
   180 >,
       
   181 <A
       
   182 HREF="sdlsurface.html"
       
   183 >SDL_Surface</A
       
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