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annotate docs/man3/SDL_LockSurface.3 @ 4159:a1b03ba2fcd0 SDL-1.2
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author | Sam Lantinga <slouken@libsdl.org> |
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date | Mon, 08 Dec 2008 00:25:42 +0000 |
parents | 4e3b250c950e |
children | 1238da4a7112 |
rev | line source |
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1 .TH "SDL_LockSurface" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" |
0 | 2 .SH "NAME" |
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4e3b250c950e
Erik Heckers fixed bug #493
Sam Lantinga <slouken@libsdl.org>
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3 SDL_LockSurface \- Lock a surface for directly access\&. |
0 | 4 .SH "SYNOPSIS" |
5 .PP | |
6 \fB#include "SDL\&.h" | |
7 .sp | |
8 \fBint \fBSDL_LockSurface\fP\fR(\fBSDL_Surface *surface\fR); | |
9 .SH "DESCRIPTION" | |
10 .PP | |
11 \fBSDL_LockSurface\fP sets up a surface for directly accessing the pixels\&. Between calls to \fBSDL_LockSurface\fP and \fBSDL_UnlockSurface\fP, you can write to and read from \fBsurface->\fBpixels\fR\fR, using the pixel format stored in \fBsurface->\fBformat\fR\fR\&. Once you are done accessing the surface, you should use \fBSDL_UnlockSurface\fP to release it\&. | |
12 .PP | |
13 Not all surfaces require locking\&. If \fBSDL_MUSTLOCK\fP(\fBsurface\fR) evaluates to \fB0\fR, then you can read and write to the surface at any time, and the pixel format of the surface will not change\&. | |
14 .PP | |
15 No operating system or library calls should be made between lock/unlock pairs, as critical system locks may be held during this time\&. | |
16 .PP | |
17 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\&. | |
18 .PP | |
19 .nf | |
20 \f(CW \&. | |
21 \&. | |
22 SDL_LockSurface( surface ); | |
23 \&. | |
24 /* Surface is locked */ | |
25 /* Direct pixel access on surface here */ | |
26 \&. | |
27 SDL_LockSurface( surface ); | |
28 \&. | |
29 /* More direct pixel access on surface */ | |
30 \&. | |
31 SDL_UnlockSurface( surface ); | |
32 /* Surface is still locked */ | |
33 /* Note: Is versions < 1\&.1\&.8, the surface would have been */ | |
34 /* no longer locked at this stage */ | |
35 \&. | |
36 SDL_UnlockSurface( surface ); | |
37 /* Surface is now unlocked */ | |
38 \&. | |
39 \&.\fR | |
40 .fi | |
41 .PP | |
42 .SH "RETURN VALUE" | |
43 .PP | |
44 \fBSDL_LockSurface\fP returns \fB0\fR, or \fB-1\fR if the surface couldn\&'t be locked\&. | |
45 .SH "SEE ALSO" | |
46 .PP | |
47 \fI\fBSDL_UnlockSurface\fP\fR | |
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48 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01 |