* 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.

/*
    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_macosx_h
#define _SDL_config_macosx_h

#include "SDL_platform.h"

/* This gets us MAC_OS_X_VERSION_MIN_REQUIRED... */
#include <AvailabilityMacros.h>

/* This is a set of defines to configure the SDL features */

#define SDL_HAS_64BIT_TYPE	1

/* Useful headers */
/* If we specified an SDK or have a post-PowerPC chip, then alloca.h exists. */
#if ( (MAC_OS_X_VERSION_MIN_REQUIRED >= 1030) || (!defined(__POWERPC__)) )
#define HAVE_ALLOCA_H		1
#endif
#define HAVE_SYS_TYPES_H	1
#define HAVE_STDIO_H	1
#define STDC_HEADERS	1
#define HAVE_STRING_H	1
#define HAVE_INTTYPES_H	1
#define HAVE_STDINT_H	1
#define HAVE_CTYPE_H	1
#define HAVE_MATH_H	1
#define HAVE_SIGNAL_H	1

/* C library functions */
#define HAVE_MALLOC	1
#define HAVE_CALLOC	1
#define HAVE_REALLOC	1
#define HAVE_FREE	1
#define HAVE_ALLOCA	1
#define HAVE_GETENV	1
#define HAVE_PUTENV	1
#define HAVE_UNSETENV	1
#define HAVE_QSORT	1
#define HAVE_ABS	1
#define HAVE_BCOPY	1
#define HAVE_MEMSET	1
#define HAVE_MEMCPY	1
#define HAVE_MEMMOVE	1
#define HAVE_MEMCMP	1
#define HAVE_STRLEN	1
#define HAVE_STRLCPY	1
#define HAVE_STRLCAT	1
#define HAVE_STRDUP	1
#define HAVE_STRCHR	1
#define HAVE_STRRCHR	1
#define HAVE_STRSTR	1
#define HAVE_STRTOL	1
#define HAVE_STRTOUL	1
#define HAVE_STRTOLL	1
#define HAVE_STRTOULL	1
#define HAVE_STRTOD	1
#define HAVE_ATOI	1
#define HAVE_ATOF	1
#define HAVE_STRCMP	1
#define HAVE_STRNCMP	1
#define HAVE_STRCASECMP	1
#define HAVE_STRNCASECMP 1
#define HAVE_SSCANF	1
#define HAVE_SNPRINTF	1
#define HAVE_VSNPRINTF	1
#define HAVE_SIGACTION	1
#define HAVE_SETJMP	1
#define HAVE_NANOSLEEP	1

/* Enable various audio drivers */
#define SDL_AUDIO_DRIVER_COREAUDIO	1
#define SDL_AUDIO_DRIVER_SNDMGR	1
#define SDL_AUDIO_DRIVER_DISK	1
#define SDL_AUDIO_DRIVER_DUMMY	1

/* Enable various cdrom drivers */
#define SDL_CDROM_MACOSX	1

/* Enable various input drivers */
#define SDL_JOYSTICK_IOKIT	1

/* Enable various shared object loading systems */
#ifdef __ppc__
/* For Mac OS X 10.2 compatibility */
#define SDL_LOADSO_DLCOMPAT	1
#else
#define SDL_LOADSO_DLOPEN	1
#endif

/* Enable various threading systems */
#define SDL_THREAD_PTHREAD	1
#define SDL_THREAD_PTHREAD_RECURSIVE_MUTEX	1

/* Enable various timer systems */
#define SDL_TIMER_UNIX	1

/* Enable various video drivers */
#define SDL_VIDEO_DRIVER_DUMMY	1
#if ((defined TARGET_API_MAC_CARBON) && (TARGET_API_MAC_CARBON))
#define SDL_VIDEO_DRIVER_TOOLBOX	1
#else
#define SDL_VIDEO_DRIVER_QUARTZ	1
#endif

/* Enable OpenGL support */
#define SDL_VIDEO_OPENGL	1

/* Disable screensaver */
#define SDL_VIDEO_DISABLE_SCREENSAVER	1

/* Enable assembly routines */
#define SDL_ASSEMBLY_ROUTINES	1
#ifdef __ppc__
#define SDL_ALTIVEC_BLITTERS	1
#endif

#endif /* _SDL_config_macosx_h */