Xrandr
XRANDR(3x) XRANDR(3x)
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:
/∗ new in 1.0 protocol, to allow reflection of screen */
/∗ reflection is applied after rotation */
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
playing 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, mit-
igating 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. Configura-
tion 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 win-
dow configuration changes occur, to update Xlib’s view of the resolu-
tion, size, rotation, reflection or subpixel order. Generally, toolk-
its 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. Toolk-
its 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
specified by draw, or returns a BadValue error. size_index specifies
which size configuration is to be used, rotation specifies which rota-
tion 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 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.Org Version 6.8.2 XRANDR(3x)
