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XRANDR(3)		   Library Functions Manual		     XRANDR(3)

	Xrandr - X Resize, Rotate and Reflection extension.

       #include	<X11/extensions/Xrandr.h>

       Bool XRRQueryExtension (Display *dpy,
	    int	*event_base_return, int	*error_base_return);

       Status XRRQueryVersion (Display *dpy,
	    int	*major_version_return,
	    int	*minor_version_return);

       XRRScreenConfiguration *XRRGetScreenInfo	(Display *dpy,
	    Drawable draw);

       void XRRFreeScreenConfigInfo (
	    XRRScreenConfiguration *config);

       Status XRRSetScreenConfig (Display *dpy,
	    XRRScreenConfiguration *config,
	    Drawable draw,
	    int	size_index,
	    Rotation rotation,
	    Time timestamp);

       Status XRRSetScreenConfigAndRate	(Display *dpy,
			     XRRScreenConfiguration *config,
			     Drawable draw,
			     int size_index,
			     Rotation rotation,
			     short rate,
			     Time timestamp);

       Rotation	XRRConfigRotations(
	    XRRScreenConfiguration *config,
	    Rotation *current_rotation);

       Time XRRConfigTimes (
	    XRRScreenConfiguration *config,
	    Time *config_timestamp);

       XRRScreenSize *XRRConfigSizes(
	    XRRScreenConfiguration *config,
	    int	*nsizes);

       short *XRRConfigRates (
	    XRRScreenConfiguration *config,
	    int	size_index,
	    int	*nrates);

       SizeID XRRConfigCurrentConfiguration (
	    XRRScreenConfiguration *config,
	    Rotation *rotation);

       short XRRConfigCurrentRate (
	    XRRScreenConfiguration *config);

       int XRRRootToScreen(
	    Display *dpy,
	    Window root);

       void XRRSelectInput(Display *dpy, Window	window,	int mask);

	* intended to take RRScreenChangeNotify,  or
	* ConfigureNotify (on the root window)
	* returns 1 if it is an	event type it understands, 0 if	not
       int XRRUpdateConfiguration(XEvent *event);

	* the following	are always safe	to call, even if RandR is
	* not implemented on a screen
       Rotation	XRRRotations(
	    Display *dpy, int screen,
	    Rotation *current_rotation);

       XRRScreenSize *XRRSizes(Display *dpy,
	    int	screen,	int *nsizes);

       short *XRRRates (Display	*dpy, int screen,
	    int	size_index, int	*nrates);

       Time XRRTimes (Display *dpy, int	screen,	Time *config_timestamp);

       display	 Specifies the connection to the X server.

       screen	 Specifies which screen.

       draw	 Specifies the screen.

       rotation	 Specifies  the	 possible  rotations  or  reflections  of  the

		 Specifies the current rotations and reflection	of the screen.

       timestamp Specifies the server timestamp.

		 Specifies the timestamp when the screen was last  (re)config-

       config	 Specifies the screen configuration being used.

       sizes	 Specifies the array of	supported sizes.

       rate	 Specifies the refresh rate in Hz.


       Can be any of:
       #define RR_Rotate_0	       1
       #define RR_Rotate_90	       2
       #define RR_Rotate_180	       4
       #define RR_Rotate_270	       8

       /* new in 1.0 protocol, to allow	reflection of screen */
       /* reflection is	applied	after rotation */

       #define RR_Reflect_X	       16
       #define RR_Reflect_Y	       32

       typedef struct {
	   int	 width,	height;
	   int	 mwidth, mheight;
       } XRRScreenSize;

       typedef struct {
	   int type;		     /*	event base */
	   unsigned long serial;     /*	# of last request processed by server */
	   Bool	send_event;	     /*	true if	this came from a SendEvent request */
	   Display *display;	     /*	Display	the event was read from	*/
	   Window window;	     /*	window which selected for this event */
	   Window root;		     /*	Root window for	changed	screen */
	   Time	timestamp;	     /*	when the screen	change occurred	*/
	   Time	config_timestamp;    /*	when the last configuration change */
	   SizeID size_index;
	   SubpixelOrder subpixel_order;
	   Rotation rotation;
	   int width;
	   int height;
	   int mwidth;
	   int mheight;
       } XRRScreenChangeNotifyEvent;

       The XRRScreenSize structure contains a possible root size in pixels and
       in millimeters.

       A XRRScreenChangeNotifyEvent is sent to a client	that has requested no-
       tification  whenever  the screen	configuration is changed. A client can
       perform this request by calling XRRSelectInput,	passing	 the  display,
       the root	window,	and the	RRScreenChangeNotifyMask mask.

       XRRScreenConfiguration is an opaque data	type containing	the configura-
       tion information	for a screen.


       Time stamps are included	and must be used to ensure the client is play-
       ing  with  a full deck: the screen may change properties	on the fly and
       this ensures its	knowledge of the configuration is up to	date.  This is
       to help issues when screens may become hot-pluggable in the future.

       Xrandr  is  a simple library designed to	interface the X	Resize and Ro-
       tate Extension.	This allows clients to change the size and rotation of
       the  root  window  of  a	 screen, along with the	ability	to reflect the
       screen about either axis	(if supported by the  implementation).	 Rota-
       tion  and  reflection  may be implemented by software and may result in
       slower performance if rotation and reflection are implemented  in  this
       fashion (as are all implementations as of October 2002).

       The  Xrandr  library  does  some	minimal	caching	to avoid roundtrips to
       provide clients frequently used information.  See "The X	Resize and Ro-
       tate  Extension"	 for  a	 detailed  description;	 also  note that depth
       switching, as described in the document is not implemented, and may (or
       may not)	ever be	implemented, as	display	memory is growing rapidly, and
       toolkits	are already beginning to  support  migration,  mitigating  the
       need  for  depth	switching.  If it is implemented in the	future,	we ex-
       pect to do so via an upward compatible extension	 to  the  current  li-
       brary/protocol; functionality described here should continue to work.

       Rotation	 and  reflection  and  how they	interact can be	confusing.  In
       Randr, the coordinate system is rotated in a  counter-clockwise	direc-
       tion  relative to the normal orientation.  Reflection is	along the win-
       dow system coordinate system, not the physical screen X and Y axis,  so
       that  rotation  and  reflection do not interact.	 The other way to con-
       sider reflection	is to treat it as specified in the  "normal"  orienta-
       tion, before rotation.

       The  XRRScreenChangeNotify  event is sent to clients that ask to	be in-
       formed whenever the root	window configuration  changes.	 Configuration
       changes	may  include  resolution,  physical  size, subpixel order (see
       XRender(3)), and	rotation.  Note	that changes to	any or	all  of	 these
       could  occur  due  to  external events (user control in the X server, a
       different monitor/flat panel display being hot-plugged) and is not only
       the result of a protocol/library	request	to the X server.

       Additionally,  to  eliminate a potential	race condition,	this event may
       be generated immediately	upon selecting for notification	if the	screen
       has  changed  since  the	client of Xrandr connected to the X server, to
       enable reliable screen resolution changing when a user may log  in  and
       change the configuration	while one or many clients are starting up.

       Xlib notification

       Clients	must  call  back  into	Xlib using XRRUpdateConfiguration when
       screen configuration change notify events are generated (or root	window
       configuration  changes  occur, to update	Xlib's view of the resolution,
       size, rotation, reflection or subpixel order.  Generally, toolkits will
       perform	this  operation	 on behalf of applications; we did not want to
       change display structure	data behind the	back of	toolkits, as in	multi-
       threaded	clients, various race conditions might occur.  Toolkits	should
       provide clients some mechanism for notification of  screen  change,  of

       There  are  two classes of interfaces: those which can be safely	called
       even if RandR is	not implemented	on a screen (to	make common idioms not
       dependent  on  the  server having support), and those which will	return
       errors if the extension is not present.

       XRRRotations returns both the  possible	set  of	 rotations/reflections
       supported  (as  a bitmask) as the value of the function,	along with the
       current rotation/reflection of the screen.

       XRRSizes	returns	the size and a pointer to the current sizes  supported
       by  the specified screen.  The first size specified is the default size
       of the server. If RandR is not supported, it returns 0 for  the	number
       of sizes.

       XRRRates	 returns  a  pointer  to  the rates supported by the specified
       size.  If RandR is not supported, it returns 0 for the number of	rates.

       XRRTimes	returns	the time last reported by the server  along  with  the
       timestamp  the  last  configuration  changed.  If the configuration has
       changed since the client	last updated its view of the server time,  re-
       quests to change	the configuration will fail until the client has an up
       to date timestamp.

       XRRRootToScreen returns the screen number given a root window (for  ex-
       ample, from an XRRScreenChangeNotifyEvent).

       The  rest  of  the functions will fail if applied to screens not	imple-
       menting the RandR extension.  XRRSetScreenConfig	sets the  screen  size
       and  rotation and reflection to the desired values on the screen	speci-
       fied by draw, or	returns	a BadValue error.  size_index specifies	 which
       size  configuration is to be used, rotation specifies which rotation or
       reflection is to	be used	(or a BadValue error is	returned).  The	 time-
       stamp is	used by	the server to make sure	the client has up to date con-
       figuration information. Status is returned to indicate success or fail-
       ure;  a	client	must refresh its configuration information if it fails
       and try the call	again (by calling XRRGetScreenInfo).

       XRRSetScreenConfigAndRate is like XRRSetScreenConfig but	also sets  the
       refresh	rate.  If  specified rate is not supported a BadValue error is

       XRRConfigRotations, XRRConfigSizes, XRRConfigCurrentConfiguration,  XR-
       RConfigTimes,  XRRConfigRates, and XRRConfigCurrentRate are used	to get
       specific	configuration information out of a screen configuration.

       XRRGetScreenInfo	returns	a screen configuration for later use; the  in-
       formation  is  private to the library.  Call XRRFreeScreenConfigInfo to
       free this information when you are finished with	it.  It	forces a round
       trip to the server.

       Other  functions	include: XRRQueryExtension which returns the event and
       error base codes, XRRQueryVersion , which returns the  current  version
       of the extension	(this information is cached by the library).

       Xrandr will remain upward compatible after the current 1.0 release.

       Jim Gettys, and Keith Packard, HP.

X Version 11			libXrandr 1.5.2			     XRANDR(3)


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