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Xrandr(3)





NAME

        Xrandr - X Resize, Rotate and Reflection extension.


SYNTAX

       #include <X11/extensions/Xrandr.h>

       Bool XRRQueryExtension (Display *dpy,
            int *event_basep, int *error_basep);

       Status XRRQueryVersion (Display *dpy,
            int *major_versionp,
            int *minor_versionp);

       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);

       XRRScreenConfiguration *XRRScreenConfig(
            Display *dpy, int screen);

       XRRScreenConfiguration *XRRConfig(Screen *screen);

       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  rotations  or  reflections  possible  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)config-
                 ured.

       config    Specifies the screen configuration being used.

       sizes     Specifies the array of sizes supported.

       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;

       XRRScreenSize  structure contains a possible root size in pixels and in
       millimeters.  XRRScreenChangeNotifyEvent Is sent to a client  that  has
       requested notification whenever the screen configuration is changed.

       XRRScreenConfiguration  This is an opaque data type containing the con-
       figuration information for a screen.

       Timestamps

       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.


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 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
       Rotate  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
       expect to do so via an  upward  compatible  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  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 is specified in the "normal" orientation, before
       rotation, if you find the other way confusing.

       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 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
       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
       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 a 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,
       requests  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
       example, 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 like  XRRSetScreenConfig  but  also  set  the
       refresh  rate.  If  specified rate is not supported a BadValue error is
       returned.

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

       XRRGetScreenInfo Returns a screen  configuration  for  later  use;  the
       information 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).


RESTRICTIONS

       Xrandr will remain upward compatible after the current 1.0 release.


AUTHOR

       Jim Gettys, and Keith Packard, HP.

X Version 11                    libXrandr 1.2.1                      XRANDR(3)

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