Mercurial > sdl-ios-xcode
annotate docs/html/sdllocksurface.html @ 1629:ef4a796e7f24
Fixed bug #55
From Christian Walther:
When writing my patch for #12, I ended up doing all sorts of changes to the way
application/window activating/deactivating is handled in the Quartz backend,
resulting in the attached patch. It does make the code a bit cleaner IMHO, but
as it might be regarded as a case of "if it ain't broken, don't fix it" I'd
like to hear other people's opinion about it. Please shout if some change
strikes you as unnecessary or wrong, and I'll explain the reasons behind it. As
far as I tested it, it does not introduce any new bugs, but I may well have
missed some.
- The most fundamental change (that triggered most of the others) is irrelevant
for the usual single-window SDL applications, it only affects the people who
are crazy enough to display other Cocoa windows alongside the SDL window (I'm
actually doing this currently, although the additional window only displays
debugging info and won't be present in the final product): Before, some things
were done on the application becoming active, some on the window becoming key,
and some on the window becoming main. Conceptually, all these actions belong to
the window becoming key, so that's what I implemented. However, since in a
single-window application these three events always happen together, the
previous implementation "ain't broken".
- This slightly changed the meaning of the SDL_APPMOUSEFOCUS flag from
SDL_GetAppState(): Before, it meant "window is main and mouse is inside window
(or mode is fullscreen)". Now, it means "window is key and mouse is inside
window (or mode is fullscreen)". It makes more sense to me that way. (See
http://developer.apple.com/documentation/Cocoa/Conceptual/WinPanel/Concepts/ChangingMainKeyWindow.html
for a discussion of what key and main windows are.) The other two flags are
unchanged: SDL_APPACTIVE = application is not hidden and window is not
minimized, SDL_APPINPUTFOCUS = window is key (or mode is fullscreen).
- As a side effect, the reorganization fixes the following two issues (and
maybe others) (but they could also be fixed in less invasive ways):
* A regression that was introduced in revision 1.42 of SDL_QuartzVideo.m
(http://libsdl.org/cgi/cvsweb.cgi/SDL12/src/video/quartz/SDL_QuartzVideo.m.diff?r1=1.41&r2=1.42)
(from half-desirable to undesirable behavior):
Situation: While in windowed mode, hide the cursor using
SDL_ShowCursor(SDL_DISABLE), move the mouse outside of the window so that the
cursor becomes visible again, and SDL_SetVideoMode() to a fullscreen mode.
What happened before revision 1.42: The cursor is visible, but becomes
invisible as soon as the mouse is moved (half-desirable).
What happens in revision 1.42 and after (including current CVS): The cursor is
visible and stays visible (undesirable).
What happens after my patch: The cursor is invisible from the beginning
(desirable).
* When the cursor is hidden and grabbed, switch away from the application using
cmd-tab (which ungrabs and makes the cursor visible), move the cursor outside
of the SDL window, then cmd-tab back to the application. In 1.2.8 and in the
current CVS, the cursor is re-grabbed, but it stays visible (immovable in the
middle of the window). With my patch, the cursor is correctly re-grabbed and
hidden. (For some reason, it still doesn't work correctly if you switch back to
the application using the dock instead of cmd-tab. I haven't been able to
figure out why. I can step over [NSCursor hide] being called in the debugger,
but it seems to have no effect.)
- The patch includes my patch for #12 (it was easier to obtain using cvs diff
that way). If you apply both of them, you will end up with 6 duplicate lines in
SDL_QuartzEvents.m.
author | Sam Lantinga <slouken@libsdl.org> |
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date | Thu, 13 Apr 2006 14:17:48 +0000 |
parents | 355632dca928 |
children |
rev | line source |
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0 | 1 <HTML |
2 ><HEAD | |
3 ><TITLE | |
4 >SDL_LockSurface</TITLE | |
5 ><META | |
6 NAME="GENERATOR" | |
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ |
0 | 8 "><LINK |
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_FreeSurface" | |
17 HREF="sdlfreesurface.html"><LINK | |
18 REL="NEXT" | |
19 TITLE="SDL_UnlockSurface" | |
20 HREF="sdlunlocksurface.html"></HEAD | |
21 ><BODY | |
22 CLASS="REFENTRY" | |
23 BGCOLOR="#FFF8DC" | |
24 TEXT="#000000" | |
25 LINK="#0000ee" | |
26 VLINK="#551a8b" | |
27 ALINK="#ff0000" | |
28 ><DIV | |
29 CLASS="NAVHEADER" | |
30 ><TABLE | |
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31 SUMMARY="Header navigation table" |
0 | 32 WIDTH="100%" |
33 BORDER="0" | |
34 CELLPADDING="0" | |
35 CELLSPACING="0" | |
36 ><TR | |
37 ><TH | |
38 COLSPAN="3" | |
39 ALIGN="center" | |
40 >SDL Library Documentation</TH | |
41 ></TR | |
42 ><TR | |
43 ><TD | |
44 WIDTH="10%" | |
45 ALIGN="left" | |
46 VALIGN="bottom" | |
47 ><A | |
48 HREF="sdlfreesurface.html" | |
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49 ACCESSKEY="P" |
0 | 50 >Prev</A |
51 ></TD | |
52 ><TD | |
53 WIDTH="80%" | |
54 ALIGN="center" | |
55 VALIGN="bottom" | |
56 ></TD | |
57 ><TD | |
58 WIDTH="10%" | |
59 ALIGN="right" | |
60 VALIGN="bottom" | |
61 ><A | |
62 HREF="sdlunlocksurface.html" | |
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63 ACCESSKEY="N" |
0 | 64 >Next</A |
65 ></TD | |
66 ></TR | |
67 ></TABLE | |
68 ><HR | |
69 ALIGN="LEFT" | |
70 WIDTH="100%"></DIV | |
71 ><H1 | |
72 ><A | |
73 NAME="SDLLOCKSURFACE" | |
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74 ></A |
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75 >SDL_LockSurface</H1 |
0 | 76 ><DIV |
77 CLASS="REFNAMEDIV" | |
78 ><A | |
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79 NAME="AEN1919" |
0 | 80 ></A |
81 ><H2 | |
82 >Name</H2 | |
83 >SDL_LockSurface -- Lock a surface for directly access.</DIV | |
84 ><DIV | |
85 CLASS="REFSYNOPSISDIV" | |
86 ><A | |
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87 NAME="AEN1922" |
0 | 88 ></A |
89 ><H2 | |
90 >Synopsis</H2 | |
91 ><DIV | |
92 CLASS="FUNCSYNOPSIS" | |
93 ><A | |
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94 NAME="AEN1923" |
0 | 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 >int <B | |
106 CLASS="FSFUNC" | |
107 >SDL_LockSurface</B | |
108 ></CODE | |
109 >(SDL_Surface *surface);</CODE | |
110 ></P | |
111 ><P | |
112 ></P | |
113 ></DIV | |
114 ></DIV | |
115 ><DIV | |
116 CLASS="REFSECT1" | |
117 ><A | |
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118 NAME="AEN1929" |
0 | 119 ></A |
120 ><H2 | |
121 >Description</H2 | |
122 ><P | |
123 ><TT | |
124 CLASS="FUNCTION" | |
125 >SDL_LockSurface</TT | |
126 > sets up a surface for directly | |
127 accessing the pixels. Between calls to <TT | |
128 CLASS="FUNCTION" | |
129 >SDL_LockSurface</TT | |
130 > | |
131 and <TT | |
132 CLASS="FUNCTION" | |
133 >SDL_UnlockSurface</TT | |
134 >, you can write to and read from | |
135 <TT | |
136 CLASS="PARAMETER" | |
137 ><I | |
138 >surface-><TT | |
139 CLASS="STRUCTFIELD" | |
140 ><I | |
141 >pixels</I | |
142 ></TT | |
143 ></I | |
144 ></TT | |
145 >, using the pixel format stored in | |
146 <TT | |
147 CLASS="PARAMETER" | |
148 ><I | |
149 >surface-><TT | |
150 CLASS="STRUCTFIELD" | |
151 ><I | |
152 >format</I | |
153 ></TT | |
154 ></I | |
155 ></TT | |
156 >. Once you are done accessing the | |
157 surface, you should use <TT | |
158 CLASS="FUNCTION" | |
159 >SDL_UnlockSurface</TT | |
160 > to release it.</P | |
161 ><P | |
162 >Not all surfaces require locking. | |
163 If <TT | |
164 CLASS="LITERAL" | |
165 >SDL_MUSTLOCK</TT | |
166 >(<TT | |
167 CLASS="PARAMETER" | |
168 ><I | |
169 >surface</I | |
170 ></TT | |
171 >) | |
172 evaluates to <SPAN | |
173 CLASS="RETURNVALUE" | |
174 >0</SPAN | |
175 >, then you can read and write to the | |
176 surface at any time, and the pixel format of the surface will not change. </P | |
177 ><P | |
178 >No operating system or library calls should be made between lock/unlock | |
179 pairs, as critical system locks may be held during this time.</P | |
180 ><P | |
181 >It should be noted, that since SDL 1.1.8 surface locks are recursive. This means that you can lock a surface multiple times, but each lock must have a match unlock. | |
182 <PRE | |
183 CLASS="PROGRAMLISTING" | |
184 > . | |
185 . | |
186 SDL_LockSurface( surface ); | |
187 . | |
188 /* Surface is locked */ | |
189 /* Direct pixel access on surface here */ | |
190 . | |
191 SDL_LockSurface( surface ); | |
192 . | |
193 /* More direct pixel access on surface */ | |
194 . | |
195 SDL_UnlockSurface( surface ); | |
196 /* Surface is still locked */ | |
197 /* Note: Is versions < 1.1.8, the surface would have been */ | |
198 /* no longer locked at this stage */ | |
199 . | |
200 SDL_UnlockSurface( surface ); | |
201 /* Surface is now unlocked */ | |
202 . | |
203 .</PRE | |
181
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204 ></P |
0 | 205 ></DIV |
206 ><DIV | |
207 CLASS="REFSECT1" | |
208 ><A | |
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209 NAME="AEN1947" |
0 | 210 ></A |
211 ><H2 | |
212 >Return Value</H2 | |
213 ><P | |
214 ><TT | |
215 CLASS="FUNCTION" | |
216 >SDL_LockSurface</TT | |
217 > returns <SPAN | |
218 CLASS="RETURNVALUE" | |
219 >0</SPAN | |
220 >, | |
221 or <SPAN | |
222 CLASS="RETURNVALUE" | |
223 >-1</SPAN | |
224 > if the surface couldn't be locked.</P | |
225 ></DIV | |
226 ><DIV | |
227 CLASS="REFSECT1" | |
228 ><A | |
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229 NAME="AEN1953" |
0 | 230 ></A |
231 ><H2 | |
232 >See Also</H2 | |
233 ><P | |
234 ><A | |
235 HREF="sdlunlocksurface.html" | |
236 ><TT | |
237 CLASS="FUNCTION" | |
238 >SDL_UnlockSurface</TT | |
239 ></A | |
240 ></P | |
241 ></DIV | |
242 ><DIV | |
243 CLASS="NAVFOOTER" | |
244 ><HR | |
245 ALIGN="LEFT" | |
246 WIDTH="100%"><TABLE | |
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247 SUMMARY="Footer navigation table" |
0 | 248 WIDTH="100%" |
249 BORDER="0" | |
250 CELLPADDING="0" | |
251 CELLSPACING="0" | |
252 ><TR | |
253 ><TD | |
254 WIDTH="33%" | |
255 ALIGN="left" | |
256 VALIGN="top" | |
257 ><A | |
258 HREF="sdlfreesurface.html" | |
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259 ACCESSKEY="P" |
0 | 260 >Prev</A |
261 ></TD | |
262 ><TD | |
263 WIDTH="34%" | |
264 ALIGN="center" | |
265 VALIGN="top" | |
266 ><A | |
267 HREF="index.html" | |
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268 ACCESSKEY="H" |
0 | 269 >Home</A |
270 ></TD | |
271 ><TD | |
272 WIDTH="33%" | |
273 ALIGN="right" | |
274 VALIGN="top" | |
275 ><A | |
276 HREF="sdlunlocksurface.html" | |
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277 ACCESSKEY="N" |
0 | 278 >Next</A |
279 ></TD | |
280 ></TR | |
281 ><TR | |
282 ><TD | |
283 WIDTH="33%" | |
284 ALIGN="left" | |
285 VALIGN="top" | |
286 >SDL_FreeSurface</TD | |
287 ><TD | |
288 WIDTH="34%" | |
289 ALIGN="center" | |
290 VALIGN="top" | |
291 ><A | |
292 HREF="video.html" | |
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293 ACCESSKEY="U" |
0 | 294 >Up</A |
295 ></TD | |
296 ><TD | |
297 WIDTH="33%" | |
298 ALIGN="right" | |
299 VALIGN="top" | |
300 >SDL_UnlockSurface</TD | |
301 ></TR | |
302 ></TABLE | |
303 ></DIV | |
304 ></BODY | |
305 ></HTML | |
306 > |