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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
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  95 NAME="AEN2049"
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  97 ><P
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  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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