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71 | ><H1 |
72 | ><A |
73 | NAME="SDLDISPLAYFORMATALPHA" |
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75 | >SDL_DisplayFormatAlpha</H1 |
76 | ><DIV |
77 | CLASS="REFNAMEDIV" |
78 | ><A |
79 | NAME="AEN2432" |
80 | ></A |
81 | ><H2 |
82 | >Name</H2 |
83 | >SDL_DisplayFormatAlpha -- Convert a surface to the display format</DIV |
84 | ><DIV |
85 | CLASS="REFSYNOPSISDIV" |
86 | ><A |
87 | NAME="AEN2435" |
88 | ></A |
89 | ><H2 |
90 | >Synopsis</H2 |
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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 |
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116 | CLASS="REFSECT1" |
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118 | NAME="AEN2442" |
119 | ></A |
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 |
142 | ></DIV |
143 | ><DIV |
144 | CLASS="REFSECT1" |
145 | ><A |
146 | NAME="AEN2449" |
147 | ></A |
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 |
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157 | ><DIV |
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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