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     72 ><A
     73 NAME="SDLSETCOLORKEY"
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     75 >SDL_SetColorKey</H1
     76 ><DIV
     77 CLASS="REFNAMEDIV"
     78 ><A
     79 NAME="AEN2045"
     80 ></A
     81 ><H2
     82 >Name</H2
     83 >SDL_SetColorKey&nbsp;--&nbsp;Sets the color key (transparent pixel) in a blittable surface and
     84 RLE acceleration.</DIV
     85 ><DIV
     86 CLASS="REFSYNOPSISDIV"
     87 ><A
     88 NAME="AEN2048"
     89 ></A
     90 ><H2
     91 >Synopsis</H2
     92 ><DIV
     93 CLASS="FUNCSYNOPSIS"
     94 ><A
     95 NAME="AEN2049"
     96 ></A
     97 ><P
     98 ></P
     99 ><PRE
    100 CLASS="FUNCSYNOPSISINFO"
    101 >#include "SDL.h"</PRE
    102 ><P
    103 ><CODE
    104 ><CODE
    105 CLASS="FUNCDEF"
    106 >int <B
    107 CLASS="FSFUNC"
    108 >SDL_SetColorKey</B
    109 ></CODE
    110 >(SDL_Surface *surface, Uint32 flag, Uint32 key);</CODE
    111 ></P
    112 ><P
    113 ></P
    114 ></DIV
    115 ></DIV
    116 ><DIV
    117 CLASS="REFSECT1"
    118 ><A
    119 NAME="AEN2055"
    120 ></A
    121 ><H2
    122 >Description</H2
    123 ><P
    124 > Sets the color key (transparent pixel) in a blittable surface and enables or
    125  disables RLE blit acceleration.</P
    126 ><P
    127 >RLE acceleration can substantially speed up blitting of images with large
    128 horizontal runs of transparent pixels (i.e., pixels that match the
    129 <TT
    130 CLASS="PARAMETER"
    131 ><I
    132 >key</I
    133 ></TT
    134 > value). The <TT
    135 CLASS="PARAMETER"
    136 ><I
    137 >key</I
    138 ></TT
    139 > must be of the same pixel format as the <TT
    140 CLASS="PARAMETER"
    141 ><I
    142 >surface</I
    143 ></TT
    144 >, <A
    145 HREF="sdlmaprgb.html"
    146 ><TT
    147 CLASS="FUNCTION"
    148 >SDL_MapRGB</TT
    149 ></A
    150 > is often useful for obtaining an acceptable value.</P
    151 ><P
    152 >If <TT
    153 CLASS="PARAMETER"
    154 ><I
    155 >flag</I
    156 ></TT
    157 > is <TT
    158 CLASS="LITERAL"
    159 >SDL_SRCCOLORKEY</TT
    160 > then
    161 <TT
    162 CLASS="PARAMETER"
    163 ><I
    164 >key</I
    165 ></TT
    166 > is the transparent pixel value in the source image of a
    167 blit.</P
    168 ><P
    169 >If <TT
    170 CLASS="PARAMETER"
    171 ><I
    172 >flag</I
    173 ></TT
    174 > is OR'd with
    175 <TT
    176 CLASS="LITERAL"
    177 >SDL_RLEACCEL</TT
    178 > then the surface will be draw using RLE
    179 acceleration when drawn with
    180 <A
    181 HREF="sdlblitsurface.html"
    182 >SDL_BlitSurface</A
    183 >.  The surface will
    184 actually be encoded for RLE acceleration the first time
    185 <A
    186 HREF="sdlblitsurface.html"
    187 >SDL_BlitSurface</A
    188 > or
    189 <A
    190 HREF="sdldisplayformat.html"
    191 >SDL_DisplayFormat</A
    192 > is called on the
    193 surface.</P
    194 ><P
    195 >If <TT
    196 CLASS="PARAMETER"
    197 ><I
    198 >flag</I
    199 ></TT
    200 > is 0, this function clears
    201 any current color key.</P
    202 ></DIV
    203 ><DIV
    204 CLASS="REFSECT1"
    205 ><A
    206 NAME="AEN2076"
    207 ></A
    208 ><H2
    209 >Return Value</H2
    210 ><P
    211 >This function returns <SPAN
    212 CLASS="RETURNVALUE"
    213 >0</SPAN
    214 >, or
    215 <SPAN
    216 CLASS="RETURNVALUE"
    217 >-1</SPAN
    218 > if there was an error.</P
    219 ></DIV
    220 ><DIV
    221 CLASS="REFSECT1"
    222 ><A
    223 NAME="AEN2081"
    224 ></A
    225 ><H2
    226 >See Also</H2
    227 ><P
    228 ><A
    229 HREF="sdlblitsurface.html"
    230 ><TT
    231 CLASS="FUNCTION"
    232 >SDL_BlitSurface</TT
    233 ></A
    234 >,
    235 <A
    236 HREF="sdldisplayformat.html"
    237 ><TT
    238 CLASS="FUNCTION"
    239 >SDL_DisplayFormat</TT
    240 ></A
    241 >,
    242 <A
    243 HREF="sdlmaprgb.html"
    244 ><TT
    245 CLASS="FUNCTION"
    246 >SDL_MapRGB</TT
    247 ></A
    248 >,
    249 <A
    250 HREF="sdlsetalpha.html"
    251 ><TT
    252 CLASS="FUNCTION"
    253 >SDL_SetAlpha</TT
    254 ></A
    255 ></P
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