annotate docs/man3/SDL_AddTimer.3 @ 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>
date Thu, 13 Apr 2006 14:17:48 +0000
parents e5bc29de3f0a
children 546f7c1eb755
rev   line source
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1 .TH "SDL_AddTimer" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference"
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2 .SH "NAME"
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3 SDL_AddTimer\- Add a timer which will call a callback after the specified number of milliseconds has elapsed\&.
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4 .SH "SYNOPSIS"
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5 .PP
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6 \fB#include "SDL\&.h"
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7 .sp
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8 \fBSDL_TimerID \fBSDL_AddTimer\fP\fR(\fBUint32 interval, SDL_NewTimerCallback callback, void *param\fR);
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9 .SH "CALLBACK"
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10 .PP
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11 .nf
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12 \f(CW/* type definition for the "new" timer callback function */
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13 typedef Uint32 (*SDL_NewTimerCallback)(Uint32 interval, void *param);\fR
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14 .fi
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15 .PP
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16 .SH "DESCRIPTION"
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17 .PP
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18 Adds a callback function to be run after the specified number of milliseconds has elapsed\&. The callback function is passed the current timer interval and the user supplied parameter from the \fBSDL_AddTimer\fP call and returns the next timer interval\&. If the returned value from the callback is the same as the one passed in, the periodic alarm continues, otherwise a new alarm is scheduled\&.
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19 .PP
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20 To cancel a currently running timer call \fISDL_RemoveTimer\fR with the timer ID returned from \fBSDL_AddTimer\fP\&.
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21 .PP
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22 The timer callback function may run in a different thread than your main program, and so shouldn\&'t call any functions from within itself\&. You may always call \fISDL_PushEvent\fR, however\&.
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23 .PP
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24 The granularity of the timer is platform-dependent, but you should count on it being at least 10 ms as this is the most common number\&. This means that if you request a 16 ms timer, your callback will run approximately 20 ms later on an unloaded system\&. If you wanted to set a flag signaling a frame update at 30 frames per second (every 33 ms), you might set a timer for 30 ms (see example below)\&. If you use this function, you need to pass \fBSDL_INIT_TIMER\fP to \fISDL_Init\fR\&.
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25 .SH "RETURN VALUE"
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26 .PP
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27 Returns an ID value for the added timer or \fBNULL\fR if there was an error\&.
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28 .SH "EXAMPLES"
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29 .PP
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30 .PP
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31 .nf
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32 \f(CWmy_timer_id = SDL_AddTimer((33/10)*10, my_callbackfunc, my_callback_param);\fR
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33 .fi
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34 .PP
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35 .SH "SEE ALSO"
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36 .PP
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37 \fI\fBSDL_RemoveTimer\fP\fR, \fI\fBSDL_PushEvent\fP\fR
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38 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01