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Original author(s)X.Org Foundation
Stable release
1.5.0[1] / May 16, 2015; 6 years ago (2015-05-16)
    PlatformX Window System
    LicenseImplementations available under various licenses

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    RandR is an extension to X11. The device driver for the display controller, CRTC, sits in the Linux kernel and exposes the KMS API to userspace.

    RandR (resize and rotate) is a communications protocol written as an extension to the X11[2] protocol. XRandR provides the ability to resize, rotate and reflect the root window of a screen. RandR is responsible for setting the screen refresh rate.[3] It allows for the control of multiple monitors.[4]

    Implementations of the protocol[edit]

    An implementation of RandR is part of the X.Org Server.[5]

    A user can use applications with a graphical front-end provided by the desktop environment (such as Gnome and KDE)[6] to control RandR, but the additional command line tool xrandr exists.[3] xrandr tells the display controller what resolution and refresh rate it should output on which of its outputs (e.g. VGA1, HDMI3). The name of the output is determined by the device driver for the display controller (KMS driver).


    The initial X11 design did not anticipate the need for dynamic resizing and it was necessary to restart the X display server to bring about the changes. However, XFree86 has, since its first release, allowed the user to change the screen resolution on the fly without changing the desktop size. The RandR extension framework brought the ability to change display characteristics without restarting the X session. The extension framework allows laptops and handheld computers to change their screen size to drive external monitors at different resolutions than their built in screens.[7]

    The RandR extension was initially implemented in the XFree86's TinyX server,[8] and partial support for version 1.0 was added to XFree86 4.3.[9][10]

    Release history[edit]

    RandR 1.1[edit]

    RandR 1.2[edit]

    RandR 1.2 permits only one virtual screen per display device. It is not possible to assign each monitor on a device to a different screen (sometimes called "Zaphod" mode), or to combine monitors from multiple devices into a single screen.[11] One practical limiting effect of this is that it is not possible to run a different WM on each monitor, since window managers are limited to one per screen.

    Some of these specific issues[which?] are resolved in RandR 1.3.[12]

    RandR 1.3[edit]

    Some of the features in version 1.3:[13]

    • Querying state without output probing
    • Multi-monitor panning (still limited to one separate screen per GPU[14])
    • Display transformations (translation, scaling, rotation, projection)
    • Standard outputs

    RandR 1.4[edit]

    Some of the features in 1.4:[15]

    • Output border adjustment properties
    • Provider objects, which allow configuration of render and output offload for multi-GPU configurations

    RandR 1.5[edit]

    Some of the features in 1.5:[16]

    • Introduction of the monitor concept to support, for example, Multi-Stream Transport devices.

    RandR 1.6[edit]

    Some of the features in 1.6:[17]

    • Introduction of the lease concept to specify screens that are not to be managed by the window manager. This is useful for Head-mounted_display devices and gaming for performance reasons.


    There are numerous graphical programs that make use of RandR to change the settings of connected screens. As can be seen in the examples, these offer fewer choices than the available command-line programs.

    The gnome-display-properties of the GNOME Control Center does not allow to set the refresh rate of a screen, the corresponding Xfce program allows configuring resolution, refresh rate, rotation and even reflection. The lxrandr program only allows to set screen resolution and refresh rate but not rotation nor reflection.

    As can be seen in the example below "#Mirroring Laptop screen on Beamer and scaling", the command-line tools xrandr enables far more interesting and useful settings.

    arandr is not a graphical program for xrandr, but a graphical front-end for xrandr. It enables the user to configure the monitor in a graphical manner and outputs the corresponding options for xrandr for that particular setup.[18]

    Clone means match largest common resolution between two monitors. Overlay can show part of other wayport (think presentations, maybe).


    Calling xrandr without parameters outputs the current state of the output ports[19]:

    Screen 0: minimum 8 x 8, current 3840 x 1080, maximum 32767 x 32767
    eDP1 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 345mm x 194mm
       1920x1080      60.0*+
       1400x1050      60.0  
       1280x1024      60.0  
       1280x960       60.0  
       1024x768       60.0  
       800x600        60.3     56.2  
       640x480        59.9  
    VGA1 disconnected (normal left inverted right x axis y axis)
    DP1 disconnected (normal left inverted right x axis y axis)
    HDMI1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 700mm x 394mm
       1280x720       50.0 +   60.0     59.9  
       1920x1080i     60.1*    50.0     60.0  
       1024x768       60.0  
       800x600        60.3  
       720x576        50.0  
       720x480        60.0     59.9  
    DP2 disconnected (normal left inverted right x axis y axis)
    HDMI2 disconnected (normal left inverted right x axis y axis)
    DP3 disconnected (normal left inverted right x axis y axis)
    HDMI3 disconnected (normal left inverted right x axis y axis)
    VIRTUAL1 disconnected (normal left inverted right x axis y axis)

    In this example, there are two monitors connected: one to "eDP1", which is a DisplayPort-Connector, and one to "HDMI1", which is a HDMI-Connector. The other outputs are detected as "disconnected". The current active modes for "eDP1" is a resolution of 1920x1080 at 60 Hz, while "HDMI1" is at 1920x1080 pixels in "interlaced" mode (hence the "i" next to the resolution).

    The position of the displays (see next section) is not immediately visible. The current resolution, for example "1920x1080+1920+0" for "eDP1" contains that information. In this example, the monitor's X-Position is shifted to the right by 1920 pixels—the X-resolution of "HDMI1"—which is "left-of" "eDP1". To aid with visualizing, there are tools like KRandRTray which show a graphical representation of the current setup. The preferred mode is denoted by the "+" sign next to a mode in the above xrandr output and is automatically selected when using "--auto", see the examples below.

    Screen position[edit]

    A common setup is to have one screen left or right of another screen. This example assumes that the output named "eDP1" is the primary screen, while VGA1 is a monitor that is placed on the left of "eDP1".

    xrandr --output VGA1 --auto --left-of eDP1

    The "--auto" parameter enables all connected but disabled outputs with their preferred mode (denoted by the "+" sign in the above xrandr output), because of that it is not always required to explicitly set parameters like resolution or refresh rate.

    Disabling an output[edit]

    Disabling an output requires the parameter "--off"

    xrandr --output VGA1 --off

    Mirroring Laptop screen on Beamer and scaling[edit]

    xrandr --fb 1600x900 --output LVDS1 --mode 1600x900 --scale 1x1 --output HDMI3 --same-as LVDS1 --mode 1920x1200 --scale-from 1600x900[20]


    Other articles of the topic Free software : PeerCast, Beanstalkd, Linux, ArkhamJS, OpenKore, Hardened Gentoo, Zclassic
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    1. http://lists.freedesktop.org/archives/xorg/2015-May/057380.html
    2. "The X Resize, Rotate and Reflect Extension Version 1.3.1".
    3. 3.0 3.1 Tyler, Chris (2008). X Power Tools. "O'Reilly Media, Inc.". pp. 86–87. ISBN 9780596101954. Retrieved 14 September 2018. Search this book on Amazon.com Logo.png
    4. Gultsch, Daniel (2009). "Dual Image » Linux Magazine". Linux Magazine (106).
    5. "git: xorg-server, RandR".
    6. Jang, Michael (2006). Linux Annoyances for Geeks: Getting the Most Flexible System in the World Just the Way You Want It. "O'Reilly Media, Inc.". p. 30. ISBN 9780596552244. Search this book on Amazon.com Logo.png
    7. The X Resize and Rotate Extension (Jim Gettys and Keith Packard, Usenix Technical Conference 2001)
    8. Gettys, Jim; Packard, Keith (4 October 2002). "The X Resize, Rotate and Reflect Extension Version 1.1". Retrieved 4 March 2016.
    9. "Release Notes for XFree86[tm] 4.3.0". XFree86 Project. Retrieved 4 March 2016.
    10. "XFree86 4.3.0 Released". Slashdot.org. 28 February 2003. Retrieved 4 March 2016.
    11. Debian XStrikeForce (documentation and information on Xrandr 1.2)
    12. Freedesktop.org GIT Repository Browser - XRandR Protocol Headers - "Add unicode art pictures for panning"
    13. "RandR 1.3 Explained, Demonstrated".
    14. "Overview of the GPU object implementation state".
    15. "X Resize and Rotate protocol headers 1.4.0".
    16. "X Resize and Rotate protocol headers 1.5.0".
    17. "X Resize and Rotate git commit 1.6.0".
    18. "ARandR: Another XRandR GUI".
    19. Nemeth, Evi (2011). UNIX and Linux System Administration Handbook. Pearson Education. p. 1025. ISBN 9780131480056. Retrieved 14 September 2018. Search this book on Amazon.com Logo.png
    20. "Opening a Window to a Wider World".

    External links[edit]

    This article "RandR" is from Wikipedia. The list of its authors can be seen in its historical and/or the page Edithistory:RandR. Articles copied from Draft Namespace on Wikipedia could be seen on the Draft Namespace of Wikipedia and not main one.