Mercurial > sdl-ios-xcode
view include/SDL_config.h.in @ 4139:568c9b3c0167 SDL-1.2
* Added configure option --enable-screensaver, to allow enabling the screensaver by default.
* Use XResetScreenSaver() instead of disabling screensaver entirely.
Full discussion summary from Erik on the SDL mailing list:
Current behaviour
=================
SDL changes the user's display power management settings without
permission from the user and without telling the user.
The interface that it uses to do so is DPMSDisable/DPMSEnable, which
should only ever be used by configuration utilities like KControl, never
by normal application programs, let alone by the libraries that they
use. Using an interface that is not at all intended for what SDL tries
to achieve means that it will not work as it should. Firstly, the power
management is completely disabled during the whole lifetime of the SDL
program, not only when it should be. Secondly, it makes SDL
non-reentrant, meaning that things will break when multiple SDL programs
are clients of the same X server simultaneously. Thirdly, no cleanup
mechanism ensures that the setting is restored if the client does not do
that (for example if it crashes).
In addition to that, this interface is broken on xorg,
[http://bugs.freedesktop.org/show_bug.cgi?id=13962], so what SDL tries
to do does not work at all on that implementation of the X Window
System. (The reason that the DPMSEnable works in KControl is that it
calls DPMSSetTimeout immediately after,
[http://websvn.kde.org/tags/KDE/3.5.9/kdebase/kcontrol/energy/energy.cpp?annotate=774532#l343]).
The problems that the current behaviour causes
==============================================
1. Information leak. When the user is away, someone might see what the
user has on the display when the user counts on the screensaver
preventing this. This does not even require physical access to the
workstation, it is enough to see it from a distance.
2. Draining battery. An SDL program that runs on a laptop will quickly
drain the battery while the user is away. The system will soon shut down
and require recharging before being usable again, while it should in
fact have consumed very little energy if the user's settings would have
been obeyed.
3. Wasting energy. Even if battery issues are not considered, energy as
such is wasted.
4. Display wear. The display may be worn out.
The problems that the current behaviour tries to solve
======================================================
1. Preventing screensaver while playing movies.
Many SDL applications are media players. They have reasons to prevent
screensavers from being activated while a movie is being played. When a
user clicks on the play button it can be interpreted as saying "play
this movie, but do not turn off the display while playing it, because I
will watch it even though I do not interact with the system".
2. Preventing screensaver when some input bypasses X.
Sometimes SDL uses input from another source than the X server, so
that the X server is bypassed. This obviously breaks the screensaver
handling. SDL tries to work around that.
3. Preventing screensaver when all input bypasses X.
There is something called Direct Graphics Access mode, where a
program takes control of both the display and the input devices from the
X server. This obviously means that the X server can not handle the
screensaver alone, since screensaver handling depends on input handling.
SDL does not do what it should to help the X server to handle the
screensaver. Nor does SDL take care of screeensaver handling itself. SDL
simply disables the screensaver completely.
How the problems should be solved
=================================
The correct way for an application program to prevent the screensaver
under X is to call XResetScreenSaver. This was recently discovered and
implemented by the mplayer developers,
[http://svn.mplayerhq.hu/mplayer?view=rev&revision=25637]. SDL needs to
wrap this in an API call (SDL_ResetScreenSaver) and implement it for the
other video targets (if they do not have a corresponding call, SDL
should do what it takes on that particular target, for example sending
fake key events).
1. When a movie is played, the player should reset the screensaver when
the animation is advanced to a new frame. The same applies to anything
similar, like slideshows.
2. When the X server is handling input, it must handle all input
(keyboards, mice, gamepads, ...). This is necessary, not only to be able
to handle the screensaver, but also so that it can send the events to
the correct (the currently active) client. If there is an input device
that the X server can not handle for some reason (such as lack of Plug
and Play capability), the program that handles the device as a
workaround must simulate what would happen if the X server would have
handled the device, by calling XResetScreenSaver when input is received
from the device.
3. When the X server is not handling the input, it depends on the
program that does to call XResetScreenSaver whenever an input event
occurs. Alternatively the program must handle the screensaver countdown
internally and call XActivateScreenSaver.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Fri, 29 Feb 2008 13:55:44 +0000 |
| parents | cd2ab40f1219 |
| children | a1b03ba2fcd0 |
line wrap: on
line source
/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2006 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Sam Lantinga slouken@libsdl.org */ #ifndef _SDL_config_h #define _SDL_config_h /* This is a set of defines to configure the SDL features */ /* General platform specific identifiers */ #include "SDL_platform.h" /* Make sure that this isn't included by Visual C++ */ #ifdef _MSC_VER #error You should copy include/SDL_config.h.default to include/SDL_config.h #endif /* C language features */ #undef const #undef inline #undef volatile /* C datatypes */ #undef size_t #undef int8_t #undef uint8_t #undef int16_t #undef uint16_t #undef int32_t #undef uint32_t #undef int64_t #undef uint64_t #undef uintptr_t #undef SDL_HAS_64BIT_TYPE /* Endianness */ #undef SDL_BYTEORDER /* Comment this if you want to build without any C library requirements */ #undef HAVE_LIBC #if HAVE_LIBC /* Useful headers */ #undef HAVE_ALLOCA_H #undef HAVE_SYS_TYPES_H #undef HAVE_STDIO_H #undef STDC_HEADERS #undef HAVE_STDLIB_H #undef HAVE_STDARG_H #undef HAVE_MALLOC_H #undef HAVE_MEMORY_H #undef HAVE_STRING_H #undef HAVE_STRINGS_H #undef HAVE_INTTYPES_H #undef HAVE_STDINT_H #undef HAVE_CTYPE_H #undef HAVE_MATH_H #undef HAVE_ICONV_H #undef HAVE_SIGNAL_H #undef HAVE_ALTIVEC_H /* C library functions */ #undef HAVE_MALLOC #undef HAVE_CALLOC #undef HAVE_REALLOC #undef HAVE_FREE #undef HAVE_ALLOCA #ifndef _WIN32 /* Don't use C runtime versions of these on Windows */ #undef HAVE_GETENV #undef HAVE_PUTENV #undef HAVE_UNSETENV #endif #undef HAVE_QSORT #undef HAVE_ABS #undef HAVE_BCOPY #undef HAVE_MEMSET #undef HAVE_MEMCPY #undef HAVE_MEMMOVE #undef HAVE_MEMCMP #undef HAVE_STRLEN #undef HAVE_STRLCPY #undef HAVE_STRLCAT #undef HAVE_STRDUP #undef HAVE__STRREV #undef HAVE__STRUPR #undef HAVE__STRLWR #undef HAVE_INDEX #undef HAVE_RINDEX #undef HAVE_STRCHR #undef HAVE_STRRCHR #undef HAVE_STRSTR #undef HAVE_ITOA #undef HAVE__LTOA #undef HAVE__UITOA #undef HAVE__ULTOA #undef HAVE_STRTOL #undef HAVE_STRTOUL #undef HAVE__I64TOA #undef HAVE__UI64TOA #undef HAVE_STRTOLL #undef HAVE_STRTOULL #undef HAVE_STRTOD #undef HAVE_ATOI #undef HAVE_ATOF #undef HAVE_STRCMP #undef HAVE_STRNCMP #undef HAVE__STRICMP #undef HAVE_STRCASECMP #undef HAVE__STRNICMP #undef HAVE_STRNCASECMP #undef HAVE_SSCANF #undef HAVE_SNPRINTF #undef HAVE_VSNPRINTF #undef HAVE_ICONV #undef HAVE_SIGACTION #undef HAVE_SETJMP #undef HAVE_NANOSLEEP #undef HAVE_CLOCK_GETTIME #undef HAVE_DLVSYM #undef HAVE_GETPAGESIZE #undef HAVE_MPROTECT #else /* We may need some replacement for stdarg.h here */ #include <stdarg.h> #endif /* HAVE_LIBC */ /* Allow disabling of core subsystems */ #undef SDL_AUDIO_DISABLED #undef SDL_CDROM_DISABLED #undef SDL_CPUINFO_DISABLED #undef SDL_EVENTS_DISABLED #undef SDL_FILE_DISABLED #undef SDL_JOYSTICK_DISABLED #undef SDL_LOADSO_DISABLED #undef SDL_THREADS_DISABLED #undef SDL_TIMERS_DISABLED #undef SDL_VIDEO_DISABLED /* Enable various audio drivers */ #undef SDL_AUDIO_DRIVER_ALSA #undef SDL_AUDIO_DRIVER_ALSA_DYNAMIC #undef SDL_AUDIO_DRIVER_ARTS #undef SDL_AUDIO_DRIVER_ARTS_DYNAMIC #undef SDL_AUDIO_DRIVER_BAUDIO #undef SDL_AUDIO_DRIVER_BSD #undef SDL_AUDIO_DRIVER_COREAUDIO #undef SDL_AUDIO_DRIVER_DART #undef SDL_AUDIO_DRIVER_DC #undef SDL_AUDIO_DRIVER_DISK #undef SDL_AUDIO_DRIVER_DUMMY #undef SDL_AUDIO_DRIVER_DMEDIA #undef SDL_AUDIO_DRIVER_DSOUND #undef SDL_AUDIO_DRIVER_PULSE #undef SDL_AUDIO_DRIVER_PULSE_DYNAMIC #undef SDL_AUDIO_DRIVER_ESD #undef SDL_AUDIO_DRIVER_ESD_DYNAMIC #undef SDL_AUDIO_DRIVER_MINT #undef SDL_AUDIO_DRIVER_MMEAUDIO #undef SDL_AUDIO_DRIVER_NAS #undef SDL_AUDIO_DRIVER_OSS #undef SDL_AUDIO_DRIVER_OSS_SOUNDCARD_H #undef SDL_AUDIO_DRIVER_PAUD #undef SDL_AUDIO_DRIVER_QNXNTO #undef SDL_AUDIO_DRIVER_SNDMGR #undef SDL_AUDIO_DRIVER_SUNAUDIO #undef SDL_AUDIO_DRIVER_WAVEOUT /* Enable various cdrom drivers */ #undef SDL_CDROM_AIX #undef SDL_CDROM_BEOS #undef SDL_CDROM_BSDI #undef SDL_CDROM_DC #undef SDL_CDROM_DUMMY #undef SDL_CDROM_FREEBSD #undef SDL_CDROM_LINUX #undef SDL_CDROM_MACOS #undef SDL_CDROM_MACOSX #undef SDL_CDROM_MINT #undef SDL_CDROM_OPENBSD #undef SDL_CDROM_OS2 #undef SDL_CDROM_OSF #undef SDL_CDROM_QNX #undef SDL_CDROM_WIN32 /* Enable various input drivers */ #undef SDL_INPUT_LINUXEV #undef SDL_INPUT_TSLIB #undef SDL_JOYSTICK_BEOS #undef SDL_JOYSTICK_DC #undef SDL_JOYSTICK_DUMMY #undef SDL_JOYSTICK_IOKIT #undef SDL_JOYSTICK_LINUX #undef SDL_JOYSTICK_MACOS #undef SDL_JOYSTICK_MINT #undef SDL_JOYSTICK_OS2 #undef SDL_JOYSTICK_RISCOS #undef SDL_JOYSTICK_WINMM #undef SDL_JOYSTICK_USBHID #undef SDL_JOYSTICK_USBHID_MACHINE_JOYSTICK_H /* Enable various shared object loading systems */ #undef SDL_LOADSO_BEOS #undef SDL_LOADSO_DLCOMPAT #undef SDL_LOADSO_DLOPEN #undef SDL_LOADSO_DUMMY #undef SDL_LOADSO_LDG #undef SDL_LOADSO_MACOS #undef SDL_LOADSO_OS2 #undef SDL_LOADSO_WIN32 /* Enable various threading systems */ #undef SDL_THREAD_BEOS #undef SDL_THREAD_DC #undef SDL_THREAD_OS2 #undef SDL_THREAD_PTH #undef SDL_THREAD_PTHREAD #undef SDL_THREAD_PTHREAD_RECURSIVE_MUTEX #undef SDL_THREAD_PTHREAD_RECURSIVE_MUTEX_NP #undef SDL_THREAD_SPROC #undef SDL_THREAD_WIN32 /* Enable various timer systems */ #undef SDL_TIMER_BEOS #undef SDL_TIMER_DC #undef SDL_TIMER_DUMMY #undef SDL_TIMER_MACOS #undef SDL_TIMER_MINT #undef SDL_TIMER_OS2 #undef SDL_TIMER_RISCOS #undef SDL_TIMER_UNIX #undef SDL_TIMER_WIN32 #undef SDL_TIMER_WINCE /* Enable various video drivers */ #undef SDL_VIDEO_DRIVER_AALIB #undef SDL_VIDEO_DRIVER_BWINDOW #undef SDL_VIDEO_DRIVER_DC #undef SDL_VIDEO_DRIVER_DDRAW #undef SDL_VIDEO_DRIVER_DGA #undef SDL_VIDEO_DRIVER_DIRECTFB #undef SDL_VIDEO_DRIVER_DRAWSPROCKET #undef SDL_VIDEO_DRIVER_DUMMY #undef SDL_VIDEO_DRIVER_FBCON #undef SDL_VIDEO_DRIVER_GAPI #undef SDL_VIDEO_DRIVER_GEM #undef SDL_VIDEO_DRIVER_GGI #undef SDL_VIDEO_DRIVER_IPOD #undef SDL_VIDEO_DRIVER_NANOX #undef SDL_VIDEO_DRIVER_OS2FS #undef SDL_VIDEO_DRIVER_PHOTON #undef SDL_VIDEO_DRIVER_PICOGUI #undef SDL_VIDEO_DRIVER_PS2GS #undef SDL_VIDEO_DRIVER_QTOPIA #undef SDL_VIDEO_DRIVER_QUARTZ #undef SDL_VIDEO_DRIVER_RISCOS #undef SDL_VIDEO_DRIVER_SVGALIB #undef SDL_VIDEO_DRIVER_TOOLBOX #undef SDL_VIDEO_DRIVER_VGL #undef SDL_VIDEO_DRIVER_WINDIB #undef SDL_VIDEO_DRIVER_WSCONS #undef SDL_VIDEO_DRIVER_X11 #undef SDL_VIDEO_DRIVER_X11_DGAMOUSE #undef SDL_VIDEO_DRIVER_X11_DYNAMIC #undef SDL_VIDEO_DRIVER_X11_DYNAMIC_XEXT #undef SDL_VIDEO_DRIVER_X11_DYNAMIC_XRANDR #undef SDL_VIDEO_DRIVER_X11_DYNAMIC_XRENDER #undef SDL_VIDEO_DRIVER_X11_VIDMODE #undef SDL_VIDEO_DRIVER_X11_XINERAMA #undef SDL_VIDEO_DRIVER_X11_XME #undef SDL_VIDEO_DRIVER_X11_XRANDR #undef SDL_VIDEO_DRIVER_X11_XV #undef SDL_VIDEO_DRIVER_XBIOS /* Enable OpenGL support */ #undef SDL_VIDEO_OPENGL #undef SDL_VIDEO_OPENGL_GLX #undef SDL_VIDEO_OPENGL_WGL #undef SDL_VIDEO_OPENGL_OSMESA #undef SDL_VIDEO_OPENGL_OSMESA_DYNAMIC /* Disable screensaver */ #undef SDL_VIDEO_DISABLE_SCREENSAVER /* Enable assembly routines */ #undef SDL_ASSEMBLY_ROUTINES #undef SDL_HERMES_BLITTERS #undef SDL_ALTIVEC_BLITTERS #endif /* _SDL_config_h */