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XRANDR(3)		    Library Functions Manual		       XRANDR(3)

NAME
      Xrandr - X Resize, Rotate and Reflection extension.

SYNTAX
     #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);

ARGUMENTS
     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 screen.

     current_rotation
	       Specifies the current rotations and reflection of the screen.

     timestamp Specifies the server timestamp.

     config_timestamp
	       Specifies the timestamp when the screen was last (re)configured.

     config    Specifies the screen configuration being used.

     sizes     Specifies the array of supported sizes.

     rate      Specifies the refresh rate in Hz.

DATATYPES
     Rotations/Reflections

     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 notifi-
     cation whenever the screen configuration is changed. A client  can  perform
     this  request by calling XRRSelectInput, passing the display, the root win-
     dow, and the RRScreenChangeNotifyMask mask.

     XRRScreenConfiguration is an opaque data type containing the  configuration
     information for a screen.

     Timestamps

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

DESCRIPTION
     Xrandr is a simple library designed to interface the X  Resize  and  Rotate
     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 ei-
     ther axis (if supported by the implementation).   Rotation  and  reflection
     may  be implemented by software and may result in slower performance if ro-
     tation and reflection are implemented in this fashion (as are all implemen-
     tations 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  Rotate  Exten-
     sion"  for  a  detailed description; also note that depth switching, as de-
     scribed 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 expect to do so via an  upward  com-
     patible  extension to the current library/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 direction relative
     to the normal orientation.  Reflection is along the window  system  coordi-
     nate system, not the physical screen X and Y axis, so that rotation and re-
     flection do not interact.	The other way to consider reflection is to treat
     it as specified in the "normal" orientation, before rotation.

     The  XRRScreenChangeNotify event is sent to clients that ask to be informed
     whenever the root window configuration changes.  Configuration changes  may
     include resolution, physical size, subpixel order (see XRender(3)), and ro-
     tation.  Note that changes to any or all of these could occur due to exter-
     nal  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 re-
     liable 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 configura-
     tion changes occur, to update Xlib's view of the  resolution,  size,  rota-
     tion,  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 multithreaded clients,
     various race conditions might occur.  Toolkits should provide clients  some
     mechanism for notification of screen change, of course.

FUNCTIONS
     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  depen-
     dent  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  sup-
     ported  (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 time-
     stamp the last configuration changed.  If	the  configuration  has  changed
     since  the  client  last  updated	its view of the server time, requests to
     change the configuration will fail until the client has an up to date time-
     stamp.

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

     The rest of the functions will fail if applied to screens not  implementing
     the  RandR extension.  XRRSetScreenConfig sets the screen size and rotation
     and reflection to the desired values on the screen specified  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 timestamp is used by the server  to
     make  sure  the  client has up to date configuration information. Status is
     returned to indicate success or failure; a client must refresh its configu-
     ration information if it fails and try  the  call	again  (by  calling  XR-
     RGetScreenInfo).

     XRRSetScreenConfigAndRate	is like XRRSetScreenConfig but also sets the re-
     fresh rate. If specified rate is not supported  a	BadValue  error  is  re-
     turned.

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

     XRRGetScreenInfo returns a screen configuration for later use; the informa-
     tion 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  er-
     ror  base codes, XRRQueryVersion , which returns the current version of the
     extension (this information is cached by the library).

RESTRICTIONS
     Xrandr will remain upward compatible after the current 1.0 release.

AUTHOR
     Jim Gettys, and Keith Packard, HP.

X Version 11			 libXrandr 1.5.4		       XRANDR(3)

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