[sdl_omap.git] / docs / html / sdlsetcolorkey.html

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>SDL_SetColorKey</TITLE
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><H1
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>SDL_SetColorKey</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN2045"
></A
><H2
>Name</H2
>SDL_SetColorKey&nbsp;--&nbsp;Sets the color key (transparent pixel) in a blittable surface and
RLE acceleration.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN2048"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN2049"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_SetColorKey</B
></CODE
>(SDL_Surface *surface, Uint32 flag, Uint32 key);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2055"
></A
><H2
>Description</H2
><P
> Sets the color key (transparent pixel) in a blittable surface and enables or
 disables RLE blit acceleration.</P
><P
>RLE acceleration can substantially speed up blitting of images with large
horizontal runs of transparent pixels (i.e., pixels that match the
<TT
CLASS="PARAMETER"
><I
>key</I
></TT
> value). The <TT
CLASS="PARAMETER"
><I
>key</I
></TT
> must be of the same pixel format as the <TT
CLASS="PARAMETER"
><I
>surface</I
></TT
>, <A
HREF="sdlmaprgb.html"
><TT
CLASS="FUNCTION"
>SDL_MapRGB</TT
></A
> is often useful for obtaining an acceptable value.</P
><P
>If <TT
CLASS="PARAMETER"
><I
>flag</I
></TT
> is <TT
CLASS="LITERAL"
>SDL_SRCCOLORKEY</TT
> then
<TT
CLASS="PARAMETER"
><I
>key</I
></TT
> is the transparent pixel value in the source image of a
blit.</P
><P
>If <TT
CLASS="PARAMETER"
><I
>flag</I
></TT
> is OR'd with
<TT
CLASS="LITERAL"
>SDL_RLEACCEL</TT
> then the surface will be draw using RLE
acceleration when drawn with
<A
HREF="sdlblitsurface.html"
>SDL_BlitSurface</A
>.  The surface will
actually be encoded for RLE acceleration the first time
<A
HREF="sdlblitsurface.html"
>SDL_BlitSurface</A
> or
<A
HREF="sdldisplayformat.html"
>SDL_DisplayFormat</A
> is called on the
surface.</P
><P
>If <TT
CLASS="PARAMETER"
><I
>flag</I
></TT
> is 0, this function clears
any current color key.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2076"
></A
><H2
>Return Value</H2
><P
>This function returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
>, or
<SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> if there was an error.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN2081"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlblitsurface.html"
><TT
CLASS="FUNCTION"
>SDL_BlitSurface</TT
></A
>,
<A
HREF="sdldisplayformat.html"
><TT
CLASS="FUNCTION"
>SDL_DisplayFormat</TT
></A
>,
<A
HREF="sdlmaprgb.html"
><TT
CLASS="FUNCTION"
>SDL_MapRGB</TT
></A
>,
<A
HREF="sdlsetalpha.html"
><TT
CLASS="FUNCTION"
>SDL_SetAlpha</TT
></A
></P
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e14743d1	1	<HTML
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	3	><TITLE
	4	>SDL_SetColorKey</TITLE
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	9	REL="HOME"
	10	TITLE="SDL Library Documentation"
	11	HREF="index.html"><LINK
	12	REL="UP"
	13	TITLE="Video"
	14	HREF="video.html"><LINK
	15	REL="PREVIOUS"
	16	TITLE="SDL_SaveBMP"
	17	HREF="sdlsavebmp.html"><LINK
	18	REL="NEXT"
	19	TITLE="SDL_SetAlpha"
	20	HREF="sdlsetalpha.html"></HEAD
	21	><BODY
	22	CLASS="REFENTRY"
	23	BGCOLOR="#FFF8DC"
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	25	LINK="#0000ee"
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	40	>SDL Library Documentation</TH
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	44	WIDTH="10%"
	45	ALIGN="left"
	46	VALIGN="bottom"
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	62	HREF="sdlsetalpha.html"
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	64	>Next</A
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67	></TABLE
68	><HR
69	ALIGN="LEFT"
70	WIDTH="100%"></DIV
71	><H1
72	><A
73	NAME="SDLSETCOLORKEY"
74	></A
75	>SDL_SetColorKey</H1
76	><DIV
77	CLASS="REFNAMEDIV"
78	><A
79	NAME="AEN2045"
80	></A
81	><H2
82	>Name</H2
83	>SDL_SetColorKey -- 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
256	></DIV
257	><DIV
258	CLASS="NAVFOOTER"
259	><HR
260	ALIGN="LEFT"
261	WIDTH="100%"><TABLE
262	SUMMARY="Footer navigation table"
263	WIDTH="100%"
264	BORDER="0"
265	CELLPADDING="0"
266	CELLSPACING="0"
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269	WIDTH="33%"
270	ALIGN="left"
271	VALIGN="top"
272	><A
273	HREF="sdlsavebmp.html"
274	ACCESSKEY="P"
275	>Prev</A
276	></TD
277	><TD
278	WIDTH="34%"
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280	VALIGN="top"
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282	HREF="index.html"
283	ACCESSKEY="H"
284	>Home</A
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287	WIDTH="33%"
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297	><TD
298	WIDTH="33%"
299	ALIGN="left"
300	VALIGN="top"
301	>SDL_SaveBMP</TD
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304	ALIGN="center"
305	VALIGN="top"
306	><A
307	HREF="video.html"
308	ACCESSKEY="U"
309	>Up</A
310	></TD
311	><TD
312	WIDTH="33%"
313	ALIGN="right"
314	VALIGN="top"
315	>SDL_SetAlpha</TD
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320	></HTML
321	>