Version 2.0
Version 2.1
     Peter Hutterer
peter.hutterer@redhat.com
      Red Hat, Inc.

1. Introduction

The X Input Extension version 2.0 (XI2) is the second major release of the X Input Extension.

XI2 provides a number of enhancements over version 1.5, including:

  • use of XGE and GenericEvents. GenericEvents are of flexible length with a minimum length of 32 bytes.

  • explicit device hierarchy of master and slave devices. See Section 4.

  • use of multiple independent master devices (Multi-Poiner X or MPX).

  • the ability for devices to change capabilities at runtime.

  • raw device events

XI2’s intent is to replace both core input processing and prior versions of the X Input Extension. Historically, the majority of applications employed the core protocol requests and events to handle user input. The core protocol does not provide information about which device generated the event. The X Input Extension version up to 1.5 requires the differentiation between core and extended devices. Extended devices may not be core devices and thus cannot be used on applications employing the core protocol. XI2 addresses both of these issues by enabling devices to be both extended and core devices and providing device information in each event (with the exception of core events).

2.1 Changes

Changes introduced by version 2.1

  • RawEvents are sent regardless of the grab state.

  • Addition of the ScrollClass for smooth scrolling

2. Notations used in this document

Notation for requests:

┌───
    Name of request
        name of request field:       type of request field
        name of request field:       type of request field
        ▶
        name of reply field:         type of reply field
└───

Notation for events:

┌───
    Name of event
        name of field:               type of field
        name of field:               type of field
└───

Complex fields are specified in the following notation:

name of field:                  COMPLEXFIELDTYPE

or, if multiple of these fields exist:

name of field:                  LISTofCOMPLEXFIELDTYPE
COMPLEXFIELDTYPE:  { name of subfield:   type of subfield,
                     name of subfield:   type of subfield }

3. Interoperability between version 1.x and 2.0

There is little interaction between 1.x and 2.x versions of the X Input Extension. Clients are requested to avoid mixing XI1.x and XI2 code as much as possible. Several direct incompatibilities are observable:

3.1 Limitations resulting from different variable ranges

XI2 provides a larger range for some fields than XI1. As a result, XI1 clients may not receive data an XI2 client receives. These fields include:

  • devices with a deviceid of greater than 127 are invisible to XI1 clients.

  • key events and key grabs featuring larger than 255 can only be sent to XI2 clients.

  • no subpixel information is available to XI1 clients. If motion events are in a subpixel range only, the server may omit these events and an XI 1.x client will not receive events until the pixel boundary is crossed.

3.2 Blocking of grabs

XI1 grabs are different to XI2 grab and a device may not be grabbed through an XI2 grab if an XI1 grab is currently active on this device or vice versa. Likewise, a keycode or button already grabbed by an XI 1.x or XI2 client may not be grabbed with the same modifier combination by an XI2 or XI 1.x client, respectively.

3.3 Invisibility of Master Devices

XI 1.x was not designed with support for multiple master devices (see Section 4). As a result, only the first master pointer and master keyboard are visible to XI 1.x clients, all other master devices are invisible and cannot be accessed from XI 1.x calls.

3.4 Smooth scrolling

Historically, X implemented scrolling events by using button press events: button 4 was one “click” of the scroll wheel upwards, button 5 was downwards, button 6 was one unit of scrolling left, and button 7 was one unit of scrolling right. This was sufficient for scroll wheel mice, but not for touchpads which are able to provide scrolling events through multi-finger drag gestures, or simply dragging your finger along a designated strip along the side of the touchpad.

Newer X servers may provide scrolling information through valuators to provide clients with more precision than the legacy button events. This scrolling information is part of the valuator data in device events. Scrolling events do not have a specific event type.

Valuators for axes sending scrolling information must have one ScrollClass for each scrolling axis. If scrolling valuators are present on a device, the server must provide two-way emulation between these valuators and the legacy button events for each delta unit of scrolling.

One unit of scrolling in either direction is considered to be equivalent to one button event, e.g. for a unit size of 1.0, -2.0 on an valuator type Vertical sends two button press/release events for button 4. Likewise, a button press event for button 7 generates an event on the Horizontal valuator with a value of +1.0. The server may accumulate deltas of less than one unit of scrolling.

Any server providing this behaviour marks emulated button or valuator events with the XIPointerEmulated flag for DeviceEvents, and the XIRawEmulated flag for raw events, to hint at applications which event is a hardware event.

If more than one scroll valuator of the same type is present on a device, the valuator marked with Preferred for the same scroll direction is used to convert legacy button events into scroll valuator events. If no valuator is marked Preferred or more than one valuator is marked with Preferred for this scroll direction, this should be considered a driver bug and the behaviour is implementation-dependent.

4. The Master/Slave device hierarchy

XI2 introduces a device hierarchy split up into so-called Master Devices (MD) and Slave Devices (SD).

4.1 Master devices

An MD is a virtual device created and managed by the server. MDs may send core events and XI events. However, an MD does not represent a physical device and relies on SDs for event generation. MDs come in two forms: as master pointers or as master keyboards. A master pointer is represented by a visible cursor on the screen. A master keyboard is represented by a keyboard focus.

Each master pointer is paired with the respective master keyboard and vice versa, and this pairing is constant for the lifetime of both input devices. Clients can use this pairing behaviour to implement input paradigms that require pointer and keyboard interation (e.g. SHIFT + Click).

4.2 Slave devices

An SD is usually a physical device configured in the server. SDs are not represented by a cursor or keyboard focus and may be attached to a master pointer or master keyboard. SDs can only be attached to any master of the same type (e.g. a physical pointer device can be attached to any master pointer).

If an event is generated by an SD

  • if the SD is attached to a master pointer, it changes the position and/or button state of the master pointer.

  • if the SD is attached to a master keyboard, it sends events to this keyboard’s focus window (if applicable) and/or changes the modifier state of this keyboard.

  • if the SD is not attached to an MD ("floating"), it does not change any master device. The SD has its own (invisible) sprite and its own focus. Both the sprite and the focus must be managed explicitly by the client program.

4.3 Event processing for attached slave devices

Whenever an SD changes its logical state,

  • the event is delivered as an XI event to any interested clients. If the device is floating, event processing stops. Otherwise, if the device is attached,

  • the master device changes its classes to reflect the SD’s capabilities. All interested clients are notified of this device change.

  • then, the event is delivered as an XI event from the MD to any interested clients. If the event has been delivered, event processing stops. Otherwise,

  • the event is delivered as a core event to any interested clients.

Given that W is the event window, and P the parent window of W, event delivery to P is only attempted if neither the XI event, nor the core event has been delivered on W. Once an event has been delivered as either XI or core event, event processing stops.

4.4. The ClientPointer principle

Many core protocol and some extension requests are ambiguous when multiple master devices are available (e.g. QueryPointer does not specify which pointer). The X server does not have the knowledge to chose the contextually correct master device. For each client, one master pointer is designated as this clients’s "ClientPointer". Whenever a client sends an ambiguous request (e.g. QueryPointer), the ClientPointer or the keyboard paired with the ClientPointer is chosen to provide the data for this request.

This ClientPointer may be explicitly assigned to a client with the SetClientPointer call. If no ClientPointer is set when a client issues an ambiguous request, the server choses one device as the ClientPointer. The method of chosing a ClientPointer from the available master pointers is implementation-specific.

If the master pointer currently set as ClientPointer for one or more clients is removed, the server may either unset the ClientPointer setting or change the ClientPointer to a different master pointer.

5. Data types

BUTTONMASK
        A binary mask defined as (1 << button number).
        A SETofBUTTONMASK is a binary OR of zero or more BUTTONMASK.
DEVICE { DEVICEID, AllDevices, AllMasterDevices }
        A DEVICE specifies either a DEVICEID or AllDevices or
        AllMasterDevices.
DEVICEID { CARD16 }
        A DEVICEID is a numerical ID for a device currently available in the
        server. The server may re-use a device ID after a device's removal.
        The device IDs 0 and 1 are reserved.
        AllDevices ........ 0
        AllMasterDevices .. 1
DEVICEUSE { MasterPointer, MasterKeyboard, SlavePointer,
            SlaveKeyboard, FloatingSlave }
        A DEVICEUSE field specifies the current use of a device in the MD/SD
        device hierarchy. See Section 4 for more information.
EVENTMASK
        An EVENTMASK is a binary mask defined as (1 << event type).
        A SETofEVENTMASK is a binary OR of zero or more EVENTMASK.
FP1616
        Fixed point decimal in 16.16 format as one INT16 and one CARD16.
        The INT16 contains the integral part, the CARD32 the decimal fraction
        shifted by 16.
FP3232
        Fixed point decimal in 32.32 format as one INT32 and one CARD32.
        The INT32 contains the integral part, the CARD32 the decimal fraction
        shifted by 32.
VALUATORMASK
        A binary mask defined as (1 << valuator number).
        A SETofVALUATORMASK is a binary OR of zero or more VALUATORMASK.

6. Errors

Errors are sent using core X error reports.

Device
        A value for a DEVICE argument does not specify a valid DEVICE.

7. Requests:

The server does not guarantee that the length of a reply remains constant in future revisions of XI2. A client must always retrieve the exact length of the protocol reply from the connection, even if the reply is longer than defined for the XI2 version supported by the client. Additional bytes in a request may include data supported in later versions of XI2. Clients should ignore this data. Padding bytes in XI2 protocol requests are required to be 0.

7.1 Requests introduced in version 2.0

┌───
    XIQueryVersion
    major_version:          CARD16
    minor_version:          CARD16
    ▶
    major_version:          CARD16
    minor_version:          CARD16
└───

The client sends the highest supported version to the server and the server sends the highest version it supports, but no higher than the requested version. Major versions changes can introduce incompatibilities in existing functionality, minor version changes introduce only backward compatible changes. It is the client’s responsibility to ensure that the server supports a version which is compatible with its expectations.

major_version
    Major XI2 version.
minor_version
    Minor XI2 version.

If major_version is less than 2, a BadValue error occurs.

┌───
    XIQueryDevice
    DEVICE                  deviceid
    ▶
    num_devices:            CARD16
    deviceinfo:             LISTofDEVICEINFO
└───
DEVICEINFO { deviceid:              DEVICEID
             use:                   DEVICEUSE
             attachment:            DEVICEID
             enabled:               BOOL
             num_classes:           CARD16
             name_len:              CARD16
             name:                  LISTofCHAR8
             classes:               LISTofCLASS }
CLASS { BUTTONCLASS, KEYCLASS, AXISCLASS, SCROLLCLASS }
BUTTONCLASS { type:                 ButtonClass
              length:               CARD16
              sourceid:             CARD16
              buttons_len:          CARD16
              state:                SETofBUTTONMASK
              labels:               LISTofATOM }
KEYCLASS    { type:                 KeyClass
              length:               CARD16
              sourceid:             CARD16
              num_keys:             CARD16
              keys:                 LISTofCARD32 }
AXISCLASS   { type:                 AxisClass
              length:               CARD16
              sourceid:             CARD16
              axisnumber:           CARD16
              label:                ATOM
              min:                  FP3232
              max:                  FP3232
              value:                FP3232
              resolution:           CARD32
              mode:                 CARD8 }
SCROLLCLASS* {type:                 ScrollClass
              length:               CARD16
              sourceid:             CARD16
              axisnumber:           CARD16
              scroll_type:          SCROLLTYPE
              flags:                SETofSCROLLFLAGS
              increment:            FP3232 }
  • since XI 2.1

    SCROLLTYPE { Vertical, Horizontal }
    SCROLLFLAGS { NoEmulation, Preferred }

XIQueryDevice details information about the requested input devices.

devices
    The device to list. If devices is AllDevices, all enabled and
    disabled devices are listed. If devices is AllMasterDevices, all
    enabled and disabled master devices are listed. If devices is a
    valid DEVICE, only this DEVICE is listed and num_devices is 1.
num_devices
    The number of deviceinfos returned.

Each deviceinfo is detailed as follows:

deviceid
    The unique ID of the device. Device IDs may get re-used when a device
    is removed.
use
    If the device is a master pointer, use is MasterPointer.
    If the device is a master keyboard, use is MasterKeyboard.
    If the device is a slave pointer, use is SlavePointer.
    If the device is a slave keyboard, use is SlaveKeyboard.
    If the device is a floating slave, use is FloatingSlave.
attachment
    If the device is a master pointer or a master keyboard, attachment
    specifies the paired master keyboard, or the paired master pointer,
    respectively.  If the device is a non-floating slave device
    attachment specifies the master device this device is attached to.
    If the device is a floating slave, attachment is undefined.
enabled
    Zero if the device is disabled, non-zero otherwise.
num_classes
    Number of classes provided.
name_len
    Length of the name in bytes not including padding.
classes
    Details the available classes provided by the device in an undefined
    order.
name
    The device's name. padded to a multiple of 4 bytes.

For all classes, type specifies the device class. Clients are required to ignore unknown device classes. The length field specifies the length of the class in 4 byte units. The following classes may occur only once: ButtonClass, KeyClass

ButtonClass:
type
    Always ButtonClass.
length
    Length in 4 byte units.
sourceid
    The device this class originates from.
num_buttons
    Number of buttons provided by the device.
labels
    List of Atoms specifying the label for each button. An Atom of None
    specifies an unlabeled button. Buttons are listed in the device-native
    order regardless of the current button mapping.
state
    The current button mask for this device after button mapping is
    applied. Each bit representing a button is 1 if this button is
    logically down, or 0 otherwise. State is a multiple of 4-byte units
    and always contains at least num_buttons bits.
KeyClass:
type
    Always KeyClass.
length
    Length in 4 byte units.
sourceid
    The device this class originates from.
num_keys
    Number of keycodes provided by the device.
keys
    List of keycodes provided.
AxisClass:
type
    Always AxisClass.
length
    Length in 4 byte units.
sourceid
    The device this class originates from.
axisnumber
    Axis number of this axis. The axis number is in device-native
    order and potential axis mappings are ignored.
label
    Atom specifying the axis name. An Atom of None specifies an unlabeled
    axis.
min
    Minimum value.
max
    Minimum value.
resolution
    Resolution in counts/meter.
mode
    Relative or Absolute.
value
    Last published axis value (if mode is absolute).

An axis in Relative mode may specify min and max as a hint to the client. If no min and max information is available, both must be 0.

ScrollClass:
type
    Always ScrollClass.
length
    Length in 4 byte units.
sourceid
    The device this class originates from.
axisnumber
    Axis number that is referred to. This axis number must be listed in
    the ValuatorClassInfo.
scroll_type:
    Vertical for a vertical scrolling axis, Horizontal for a horizontal
    scrolling axis.
flags:
    A set of flags that apply to this scroll axis.
    NoEmulation: no legacy scroll button events are generated for events
                 on this scrolling axis.
    Preferred: This axis is the preferred axis for emulating valuator
               events from legacy scroll button events.
increment:
    The valuator delta equivalent to one positive unit of scrolling.

A ScrollClass may only exist if the device has at least one ValuatorClass and each axisnumber listed in any ScrollClass. Only one ScrollClass may exist per ValuatorClass.

┌───
    XISelectEvents
        window:         Window
        num_masks:      CARD16
        masks:          LISTofEVENTMASK
└───
EVENTMASK { deviceid:          DEVICE,
            mask_len:          CARD16,
            mask:              SETofEVENTMASK
window
    The window to select the events on.
num_masks
    Number of items in masks.
deviceid
    Numerical deviceid, or AllDevices, or AllMasterDevices.
mask_len
    Length of mask in 4 byte units.
mask
    Event mask. An event mask for an event type T is defined as (1 << T).

XISelectEvents selects for XI2 events on window.

If num_masks is 0, a BadValue error occurs.

Each mask sets the (and overwrites a previous) event mask for the DEVICE specified through deviceid. The device AllDevices or AllMasterDevices is treated as a separate device by server. A client’s event mask is the union of AllDevices, AllMasterDevices and the per-device event mask. The removal of device from the server unsets the event masks for the device. If an event mask is set for AllDevices or AllMasterDevices, the event mask is not cleared on device removal and affects all future devices.

If mask_len is 0, the event mask for the given device is cleared.

The mask for XIHierarchyEvents may only be selected for XIAllDevices. Setting it for any other device results in a BadValue error.

┌───
    XIGetSelectedEvents
        window:         Window
        ▶
        num_masks:      CARD16
        masks:          LISTofEVENTMASK
└───
window
    The window to select the events on.
num_masks
    Number of items in masks.
masks
    Selected event masks by this client.

Masks are returned on a per-device basis, with masks for AllDevices and AllMasterDevices returned separately. A client can calculate the effective mask for a device with a bitwise OR of the AllDevices, the AllMasterDevices and the device-specific mask.

If num_masks is 0, no events have been selected by this client on the given window.

┌───
    XIQueryPointer
        window:         Window
        deviceid:       DEVICEID
        ▶
        root:           Window
        child:          Window
        root_x:         FP1616
        root_y:         FP1616
        win_x:          FP1616
        win_y:          FP1616
        same_screen:    BOOL
        mods:           MODIFIERINFO
        group:          GROUPINFO
        buttons_len:    CARD16
        buttons:        SETofBUTTONMASK
└───

Query a master pointer device for its current position.

root
    The root window the pointer is logically on.
child
    The child window of window that contains the pointer or None.
root_x
root_y
    Pointer position relative to the root window's origin.
win_x
win_y
    Pointer position relative to window or 0 if same_screen is false.
same_screen
    True if window is on the same screen as the pointer.
mods
    XKB modifier state on the paired device.
group
    XKB group state on the paired device.
buttons_len
    The length of buttons in 4 byte units.
buttons
    Button state.

If the device is not a master pointer device or not a floating slave pointer, a BadDevice error results.

┌───
    XIWarpPointer
        src_win:         Window
        dst_win:         Window
        src_x:           FP1616
        src_y:           FP1616
        src_width:       INT16
        src_height:      INT16
        dst_x:           FP1616
        dst_y:           FP1616
        deviceid:        DEVICEID
└───

WarpPointer moves the pointer of deviceid as if the user had moved the pointer. WarpPointer can only be called for MasterPointer and FloatingSlave devices.

src_win
   If src_window is not None, the move only takes place if src_window
   contains the pointer and the pointer is contained in the specified
   rectangle of src_window.
dst_win
   If dst_win is None, this request moves the pointer by offsets
   dst_x/dst_y relative to the current position of the pointer. If
    dst_window is a window, this request moves the pointer to
   dst_x/dst_y relative to dst_win's origin.
src_x
src_y
src_width
src_height
   Specifies the source window rectangle.
dst_x
dst_y
    The relative coordinates to move the pointer if dst_win is None, or
    the absolute coordinates if dst_win is a window.
deviceid
    The device to warp.

This request cannot be used to move the pointer outside the confine-to window of an active pointer grab. An attempt will only move the pointer as far as the closest edge of the confine-to window.

This request will generate events just as if the user had instantaneously moved the pointer.

┌───
    XIChangeCursor
        win:             Window
        cursor:          Cursor
        deviceid:        DEVICEID
└───

Change a master pointer’s cursor on the specified window.

window
    The window.
cursor
    The new cursor or None.
deviceid
    The master pointer device.

Whenever device enters a window W, the cursor shape is selected in the following order:

  • if the current window has a device cursor C(d) defined for device, display this cursor C(d).

  • otherwise, if the current window has a cursor C(w) defined in the core protocol’s window attributes, display cursor C(w).

  • repeat on parent window until a cursor has been found.

The device cursor for a given window is reset once the window is destroyed or the device is removed, whichever comes earlier.

If deviceid does not specify a master pointer, a BadDevice error is returned.

┌───
    XIChangeHierarchy
        num_changes:     CARD8
        changes:         LISTofHIERARCHYCHANGES
└───
HIERARCHYCHANGE { ADDMASTER, REMOVEMASTER, ATTACHSLAVE, DETACHSLAVE }
HIERARCHYCHANGETYPE { AddMaster, RemoveMaster, AttachSlave, DetachSlave }
CHANGEMODE { Float, Attach }
ADDMASTER { type:        HIERARCHYCHANGETYPE
            length:      CARD16
            name_len:    CARD16
            send_core:   BOOL
            enable:      BOOL
            name:        LISTofCHAR8 }
REMOVEMASTER { type:            HIERARCHYCHANGETYPE
               length:          CARD16
               deviceid:        DEVICEID
               return_mode:     CHANGEMODE
               return_pointer:  DEVICEID
               return_keyboard: DEVICEID }
ATTACHSLAVE   { type:        HIERARCHYCHANGETYPE
                length:      CARD16
                deviceid:    DEVICEID
                master:      DEVICEID }
DETACHSLAVE { type:       HIERARCHYCHANGETYPE
              length:     CARD16
              deviceid:   DEVICEID }

XIChangeHierarchy allows a client to modify the MD/SD device hierarchy (see Section 4).

num_changes
    The number of changes to apply to the current hierarchy.
changes
    The list of changes.

The server processes the changes in the order received from the client and applies each requested change immediately. If an error occurs, processing stops at the current change and returns the number of successfully applied changes in the error.

ADDMASTER creates a pair of master devices.
type
    Always AddMaster.
length
    Length in 4 byte units.
name_len
    Length of name in bytes.
send_core
    True if the device should send core events.
enable
    True if the device is to be enabled immediately.
name
    The name for the new master devices. The master pointer's name is
    automatically appended with " pointer", the master keyboard's name is
    automatically appended with " keyboard".
REMOVEMASTER removes an existing master device.
type
    Always RemoveMaster.
length
    Length in 4 byte units.
deviceid
    The device to remove.
return_mode
    Return mode for attached slave devices.
    If return_mode is Float, all slave devices are set to floating.
    If return_mode is Attach, slave pointers are attached to
    return_pointer and slave keyboards are attached to
    return_keyboard.
return_pointer
return_keyboard
    The master pointer and master keyboard to attach slave devices to, if
    return_mode is Attach. If return_mode is Float, return_pointer
    and return_keyboard are undefined.

Removing a master pointer removes the paired master keyboard and vice versa.

ATTACHSLAVE attaches a slave device to a given master device.
type
    Always ChangeAttachment.
length
    Length in 4 byte units.
deviceid
    Deviceid of the slave device.
master
    The new master device to attach this slave device to.
DETACHSLAVE detaches a slave device from its current master device.
type
    Always ChangeAttachment.
length
    Length in 4 byte units.
deviceid
    Deviceid of the slave device.
┌───
    XISetClientPointer
        win:             Window
        deviceid:        DEVICEID
└───

Set the ClientPointer for the client owning win to the given device.

win
     Window or client ID.
deviceid
     The master pointer or master keyboard that acts as ClientPointer.

Some protocol requests are ambiguous and the server has to choose a device to provide data for a request or a reply. By default, the server will choose a client’s ClientPointer device to provide the data, unless the client currently has a grab on another device. See section 4.4 for more details.

If win is None, the ClientPointer for this client is set to the given device. Otherwise, if win is a valid window, the ClientPointer for the client owning this window is set to the given device. Otherwise, if win is not a valid window but a client with the client mask equal to win exists, this client’s ClientPointer is set to the given device.

If deviceid does not specify a master pointer or master keyboard, a BadDevice error is returned.

If window does not specify a valid window or client ID and is not None, a BadWindow error is returned.

┌───
    XIGetClientPointer
        win:             Window
        ▶
        set:             BOOL
        deviceid:        DEVICEID
└───

Query the ClientPointer for the client owning win.

win
    The window or client ID.
set
    True if the client has a ClientPointer set.
deviceid
    The master pointer that acts as a ClientPointer if set is True.

No difference is made between a ClientPointer set explicitly through XISetClientPointer and a ClientPointer implicitly assigned by the server in response to an ambiguous request.

┌───
    XISetFocus
        focus:           Window
        deviceid:        DEVICEID
        time:            Time
└───

Set the focus for the given device to the given window. Future key events from this device are sent to this window. This request generates FocusIn and FocusOut events.

focus
    A viewable window or None.
deviceid
    The device to modify the focus window for.
time
    Specifies the time to change the focus or CurrentTime.

If focus is None, key events from this device are discarded until a new focus window is set. If focus is a viewable window, key events from this device are sent to this window. If the window becomes unviewable, the window’s first viewable ancestor automatically becomes the focus window and FocusIn and FocusOut events are sent as if a client had changed the focus window. This is equivalent to RevertToParent in the core XSetInputFocus window.

This request has no effect if the specified time is earlier than the current last-focus-change time or is later than the current X server time. Otherwise, the last-focus-change time is set to the specified time.

┌───
    XIGetFocus
        deviceid:        DEVICEID
        ▶
        focus:           Window
└───

Return the current focus window for the given device.

┌───
    XIGrabDevice
        deviceid:        DEVICEID
        grab_window:     Window
        owner_events:    BOOL
        grab_mode:       { Synchronous, Asynchronous }
        paired_device_mode: { Synchronous, Asynchronous }
        time:            TIMESTAMP or CurrentTime
        cursor:          Cursor
        mask_len:        CARD16
        masks:           SETofEVENTMASK
        ▶
        status:          Success, AlreadyGrabbed, Frozen, InvalidTime, NotViewable
└───

This request actively grabs control of the specified input device. Further input events from this device are reported only to the grabbing client. This request overides any previous active grab by this client for this device.

deviceid
    The device to grab.
grab_window
    Events are reported relative to the grab window.
owner_events
    Specifies whether event will be reported normally or relative to the
    grab window.
grab_mode
    Specifies if this device will be frozen as a result of the grab.
paired_device_mode
    Specifies if the master device paired with this device will be frozen
    as a result of the grab.
time
    A valid server time or CurrentTime.
cursor
    The cursor to display for the duration of the grab or None.
mask_len
    Length of mask in 4 byte units.
mask
    Event mask. An event mask for an event type T is defined as (1 << T).
status
    Success or the reason why the grab could not be established.

The masks parameter specifies which events the client wishes to receive while the device is grabbed.

If owner-events is False, input events generated from this device are reported with respect to grab-window, and are only reported if selected by being included in the event-list. If owner-events is True, then if a generated event would normally be reported to this client, it is reported normally, otherwise the event is reported with respect to the grab-window, and is only reported if selected by being included in the event-list. For either value of owner-events, unreported events are discarded.

If grab-mode is Asynchronous, device event processing continues normally. If the device is currently frozen by this client, then processing of device events is resumed. If grab-mode is Synchronous, the state of the grabbed device (as seen by means of the protocol) appears to freeze, and no further device events are generated by the server until the grabbing client issues a releasing XIAllowEvents request or until the device grab is released. Actual device input events are not lost while the device is frozen; they are simply queued for later processing.

If the device is a slave device, the paired-device-mode is ignored. Otherwise, if this device is a master device and paired-device-mode is Asynchronous, event processing is unaffected by activation of the grab. If this device is a master device and paired-device-mode is Synchronous, the state of the master device paired with this device (as seen by means of the protocol) appears to freeze, and no further events are generated by the server until the grabbing client issues a releasing XIAllowEvents request or until the device grab is released. Actual events are not lost while the devices are frozen; they are simply queued for later processing.

If the cursor is not None and the device is a master pointer device, the cursor will be displayed until the device is ungrabbed.

This request fails and returns:

AlreadyGrabbed: If the device is actively grabbed by some other client.
NotViewable: If grab-window is not viewable.
InvalidTime: If the specified time is earlier than the last-grab-time for
             the specified device or later than the current X server time.
             Otherwise, the last-grab-time for the specified device is set
             to the specified time and CurrentTime is replaced by the
             current X server time.
Frozen: If the device is frozen by an active grab of another client.

To release a grab of a device, use XIUngrabDevice.

┌───
    XIUngrabDevice
        deviceid:        DEVICEID
        time:            TIMESTAMP or CurrentTime
└───

This request releases the device if this client has it actively grabbed (from either XIGrabDevice or XIPassiveGrabDevice) and releases any queued events. If any devices were frozen by the grab, XIUngrabDevice thaws them.

deviceid
    The device to grab.
time
    A valid server time or CurrentTime.

The request has no effect if the specified time is earlier than the last-device-grab time or is later than the current server time. This request generates FocusIn and FocusOut events. An XIUngrabDevice is performed automatically if the event window for an active device grab becomes not viewable.

┌───
    XIAllowEvents:
        deviceid:        DEVICEID
        time:            TIMESTAMP or CurrentTime
        event_mode:      { AsyncDevice, SyncDevice,
                           AsyncPairedDevice, SyncPairedDevice,
                           ReplayDevice, AsyncPair, SyncPair }
└───

The XIAllowEvents request releases some queued events if the client has caused a device to freeze.

deviceid
    The device to grab.
time
    A valid server time or CurrentTime.
event_mode
    Specifies whether a device is to be thawed and events are to be
    replayed.

The request has no effect if the specified time is earlier than the last-grab time of the most recent active grab for the client, or if the specified time is later than the current X server time.

The following describes the processing that occurs depending on what constant you pass to the event-mode argument:

AsyncDevice:
    If the specified device is frozen by the client, event processing for that
    device continues as usual. If the device is frozen multiple times  by the
    client on behalf of multiple separate grabs, AsyncDevice thaws for
    all.
    AsyncDevice has no effect if the specified device is not frozen by the
    client, but the device need not be grabbed by the client.
SyncDevice:
    If the specified device is frozen and actively grabbed by the client,
    event processing for that device continues normally until the next
    event is reported to the client. At this time, the specified device
    again appears to freeze. However, if the reported event causes the
    grab to be released, the specified device does not freeze.
    SyncDevice has no effect if the specified device is not frozen by the
    client or is not grabbed by the client.
 ReplayDevice:
    If the specified device is actively grabbed by the client and is frozen
    as the result of an event having been sent to the client (either from
    the activation of a XIGrabButton or from a previous XIAllowEvents with
    mode SyncDevice, but not from a Grab), the grab is released and
    that event is completely reprocessed.  This time, however, the request
    ignores any passive grabs at or above (towards the root) the
    grab-window of the grab just released.
    The request has no effect if the specified device is not grabbed by
    the client or if it is not frozen as the result of an event.
 AsyncPairedDevice
    If the paired master device is frozen by the client, event processing
    for it continues as usual. If the paired device is frozen multiple
    times by the client on behalf of multiple separate grabs,
    AsyncPairedDevice thaws for all.
    AsyncPairedDevice has no effect if the device is not frozen by the
    client, but those devices need not be grabbed by the client.
    AsyncPairedDevice has no effect if deviceid specifies a slave device.
 SyncPairedDevice
    If the paired master device is frozen by the client, event processing (for
    the paired master device) continues normally until the next button or key
    event is reported to the client for the grabbed device (button event for
    the grabbed device, key or motion event for the device), at which time
    the device again appears to freeze. However, if the reported event causes
    the grab to be released, then the device does not freeze.
    SyncPairedDevice has no effect if the specified device is not grabbed
    by the client or if it is no frozen as the result of an event.
    SyncPairedDevice has no effect if deviceid specifies a slave device.
 SyncPair
    If both the device and the paired master device are frozen by the
    client, event processing (for both devices) continues normally until
    the next XIButtonPress, XIButtonRelease, XIKeyPress, or XIKeyRelease
    event is reported to the client for a grabbed device (button event for
    a pointer, key event for a keyboard), at which time the devices again
    appear to freeze. However, if the reported event causes the grab to be
    released, then the devices do not freeze (but if the other device is
    still grabbed, then a subsequent event for it will still cause both
    devices to freeze).
    SyncPair has no effect unless both the device and the paired master
    device are frozen by the client. If the device or paired master device
    is frozen twice by the client on behalf of two separate grabs,
    SyncPair thaws for both (but a subsequent freeze for SyncPair will
    only freeze each device once).
    SyncPair has no effect if deviceid specifies a slave device.
 AsyncPair
    If the device and the paired master device are frozen by the client,
    event processing for both devices continues normally. If a device is
    frozen twice by the client on behalf of two separate grabs, AsyncBoth
    thaws for both. AsyncPair has no effect unless both the device and the
    paired master device frozen by the client.
    AsyncPair has no effect if deviceid specifies a slave device.
┌───
    XIPassiveGrabDevice
        deviceid:        DEVICE
        detail:          CARD32
        grab_type:       GRABTYPE
        grab_window:     Window
        cursor:          Cursor
        owner_events:    Bool
        grab_mode:       { Synchronous, Asynchronous }
        paired_device_mode: { Synchronous, Asynchronous }
        num_modifiers:   INT16
        mask_len:        CARD16
        masks:           SETofEVENTMASK
        modifiers:       CARD32 or GrabAnyModifier
        ▶
        num_modifiers_return:    INT16
        modifiers_return:        GRABMODIFIERINFO
└───
GRABTYPE         { GrabtypeButton, GrabtypeKeycode, GrabtypeEnter,
                   GrabtypeFocusIn}
GRABMODIFIERINFO {   status:    Access
                     modifiers: CARD32 }

Establish an explicit passive grab for a button or keycode on the specified input device.

cursor
    The cursor to display for the duration of the grab. If grab_type
    is not GrabtypeButton, this argument is ignored.
deviceid
    The device to establish the passive grab on or AllDevices or
    AllMasterDevices.
detail
    The button number, or key symbol to grab for.
    Must be 0 for GrabtypeEnter and GrabtypeFocusIn.
grab_type
    The type of grab to establish.
grab_window
    Events are reported relative to the grab window.
grab_mode
    If grab-mode is Asynchronous, device event processing continues
    normally.  If the device is currently frozen by this client, then
    processing of device events is resumed. If grab-mode is
    Synchronous, the state of the grabbed device (as seen by means of
    the protocol) appears to freeze, and no further device events are
    generated by the server until the grabbing client issues a
    releasing XIAllowEvents request or until the device grab is
    released. Actual device input events are not lost while the device
    is frozen; they are simply queued for later processing.
mask_len
    Length of mask in 4 byte units.
mask
    Event mask. An event mask for an event type T is defined as (1 << T).
modifiers
    XKB modifier state to activate this passive grab.
num_modifiers
    Number of elements in modifiers.
owner_events
    Specifies whether event will be reported normally or relative to the
    grab window.
num_modifiers_return
    Number of elements in modifiers_return
modifiers_return
    XKB modifier state that could not be grabbed.

If owner-events is False, input events generated from this device are reported with respect to grab-window, and are only reported if selected by being included in the event-list. If owner-events is True, then if a generated event would normally be reported to this client, it is reported normally, otherwise the event is reported with respect to the grab-window, and is only reported if selected by being included in the event-list. For either value of owner-events, unreported events are discarded.

If deviceid specifies a master pointer, the modifiers of the paired master keyboard are used. If deviceid specifies a slave pointer the modifiers of the master keyboard paired with the attached master pointers are used. If deviceid specifies a slave keyboard, the modifiers of the attached master keyboard are used. Note that activating a grab on a slave device detaches the device from its master. In this case, the modifiers after activation of the grab are from the slave device only and may be different to the modifier state when the grab was triggered.

In the future, if grab_type is GrabtypeButton or GrabtypeKeyboard, the device is actively grabbed if:

  • the device is not grabbed, and

  • the specified modifier keys are down, and

  • the grab_type is GrabtypeButton and the button specified in detail is logically pressed or the grab_type is GrabtypeKeycode and the keycode specified in detail is logically pressed, and

  • the grab_window contains the pointer, and

  • a passive grab on the same button/keycode + modifier combination does not exist on an ancestor of grab_window.

Otherwise, if grab_type is GrabtypeEnter or GrabtypeFocusIn, the device is actively grabbed if:

  • the device is not actively grabbed, and

  • the specified modifier keys are down, and

  • the grab_type is GrabtypeEnter and the device’s pointer has moved into grab_window or a descendant of grab_window, or the grab_type is GrabtypeFocusIn and the device’s focus has been set to the grab_window or a descendant of grab_window,

  • a passive grab of the same grab_type + modifier combination does not does not exist on an ancestor of grab_window.

A modifier of GrabAnyModifier is equivalent to issuing the request for all possible modifier combinations (including no modifiers). A client may request a grab for GrabAnyModifier and explicit modifier combinations in the same request.

A GrabtypeButton or GrabtypeKeyboard grab is released when all buttons or keycode are released, independent of the state of modifier keys. A GrabtypeEnter or GrabtypeFocusIn grab is released when the pointer or focus leaves the window and all of its descendants, independent of the state of modifier keys. Note that the logical state of a device (as seen by means of the protocol) may lag the physical state if device event processing is frozen.

This request overrides all previous passive grabs by the same client on the same button/key/enter/focus in + modifier combinations on the same window.

If some other client already has issued a XIPassiveGrabDevice request with the same button or keycode and modifier combination, the failed modifier combinations is returned in modifiers_return. If some other client already has issued an XIPassiveGrabDevice request of grab_type XIGrabtypeEnter or XIGrabtypeFocusIn with the same grab_window and the same modifier combination, the failed modifier combinations are returned in modifiers_return. If num_modifiers_return is zero, all passive grabs have been successful.

If a button grab or enter grab activates, EnterNotify and LeaveNotify events with mode Grab are generated as if the pointer were to suddenly warp from its current position some position in the grab_window. However, the pointer does not warp, and the pointer position is used as both the initial and final positions for the events.

If a keycode grab or focus grab activates, FocusIn and FocusOut events with mode Grab are generated as if the focus were to change from the current window to the grab_window.

If an enter or focus in grab activates, additional EnterNotify events with mode XIPassiveGrabNotify are generated as if the pointer or focus were to suddenly warp from its current position to some position in the grab window. These events are sent to the grabbing client only and only if the grab event mask has selected for it. If such a passive grab deactivates, addional LeaveNotify events with mode XIPassiveUngrabNotify are generated and sent to the grabbing client before the grab deactivates.

┌───
    XIPassiveUngrabDevice
        deviceid:        DEVICEID
        detail:          CARD32
        grab_type:       GRABTYPE
        grab_window:     Window
        num_modifiers:   INT16
        modifiers:       MODIFIERINFO
└───

Release an explicit passive grab on the specified input device.

deviceid
    The device to establish the passive grab on.
detail
    The button number or key symbol to ungrab.
    Must be 0 for GrabtypeEnter and GrabtypeFocusIn.
grab_type
    The type of grab to establish.
grab_window
    Events are reported relative to the grab window.
modifiers
    XKB modifier state to activate this passive grab.
num_modifiers
    Number of elements in modifiers.

This request has no effect if the client does not have a passive grab of the same type, same button or keycode (if applicable) and modifier combination on the grab_window.

┌───
    XIListProperties
        deviceid:        DEVICEID
        ▶
        num_properties:  INT16
        properties:      LISTofATOM
└───

List the properties associated with the given device.

deviceid
    The device to list the properties for.
num_atoms
    Number of atoms in the reply
atoms
    All properties on the device.
┌───
    XIChangeProperty
        deviceid:        DEVICEID
        property:        ATOM
        type:            ATOM
        format:          { 8, 16, 32 }
        mode:            { Append, Prepend, Replace }
        num_items:       CARD32
        data:            LISTofINT8, or LISTofINT16, or LISTofINT32
└───

Change the given property on the given device.

deviceid
    The device to change the property on.
property
    The property to modify.
type
    The property's type.
mode
    One of Append, Prepend, or Replace
num_items
    Number of items following this request.
data
    Property data (nitems * format/8 bytes)

The type is uninterpreted by the server. The format specifies whether the data should be viewed as a list of 8-bit, 16-bit, or 32-bit quantities so that the server can correctly byte-swap as necessary.

If the mode is Replace, the previous propert y value is discarded. If the mode is Prepend or Append, then the type and format must match the existing property value (or a Match error results). If the property is undefined, it is treated as defined with the correct type and format with zero-length data. For Prepend, the data is tacked on to the beginning of the existing data, and for Append, it is tacked on to the end of the existing data.

The lifetime of a property is not tied to the storing client. Properties remain until explicitly deleted, until the device is removed, or until server reset.

A property cannot be deleted by setting nitems to zero. To delete a property, use XIDeleteProperty.

This request generates an XIPropertyEvent.

┌───
    XIDeleteProperty
        deviceid:        DEVICEID
        property:        ATOM
└───

Deletes the given property on the given device.

deviceid
    The device to delete the property on.
property
    The property to delete.

If the property is deleted, an XIPropertyEvent is generated on the device. If the property does not exist, this request does nothing.

┌───
    XIGetProperty
        deviceid:        DEVICEID
        property:        ATOM
        type:            Atom or AnyPropertyType
        offset:          CARD32
        len:             CARD32
        delete:          BOOL
        ▶
        type:            Atom
        bytes_after:     CARD32
        num_items:       CARD32
        format:          { 8, 16, 32 }
        data:            LISTofINT8, or LISTofINT16, or LISTofINT32
└───

Get the data for the given property on the given device.

deviceid
    The device to retrieve the property data from.
property
    The property to retrieve the data from..
type
    The property type to retrieve or AnyPropertyType
offset
    The offset in 4-byte units.
len
    Number of bytes to receive in 4-byte units.
delete
    Delete the property after retrieving the data.
bytes_after
    Number of unread bytes in the stored property
num_items
    Number of items in data
format
    8, 16, or 32
data
    Property data (nitems * format/8 bytes)

If the specified property does not exist for the specified device, then the return type is None, the format and bytes-after are zero, and the value is empty. The delete argument is ignored in this case. If the specified property exists but its type does not match the specified type, then the return type is the actual type of the property, the format is the actual format of the property (never zero), the bytes-after is the length of the property in bytes (even if the format is 16 or 32), and the value is empty. The delete argument is ignored in this case. If the specified property exists and either AnyPropertyType is specified or the specified type matches the actual type of the property, then the return type is the actual type of the property, the format is the actual format of the property (never zero), and the bytes-after and value are as follows, given:

N = actual length of the stored property in bytes
   (even if the format is 16 or 32)
I = 4 * long-offset
T = N−I
L = MINIMUM(T, 4 * long-length)
A = N − (I + L)

The returned value starts at byte index I in the property (indexing from 0), and its length in bytes is L. However, it is a Value error if offset is given such that L is negative. The value of bytes_after is A, giving the number of trailing unread bytes in the stored property. If delete is True and the bytes_after is zero, the property is also deleted from the device, and a XIPropertyNotify event is generated on the device.

8. Events:

An event specifies its length in 4-byte units after the initial 32 bytes. Future versions of the protocol may provide additional information in the same event, thus increasing the event size. Clients are required to always read the number of bytes specified by the event, not the size of the event they may have been compiled against.

The following event types are available in XI2.

Version 2.0: HierarchyChanged DeviceChanged KeyPress KeyRelease ButtonPress ButtonRelease Motion RawKeyPress RawKeyRelease RawButtonPress RawButtonRelease RawMotion Enter Leave FocusIn FocusOut PropertyEvent

All events have a set of common fields specified as EVENTHEADER.

EVENTHEADER { type:                       BYTE
              extension:                  BYTE
              sequenceNumber:             CARD16
              length:                     CARD32
              evtype:                     CARD16
              deviceid:                   DEVICEID
              time:                       Time }
type
    Always GenericEvent.
extension
    Always the X Input extension offset.
sequenceNumber
    Sequence number of last request processed by the server.
length
    Length in 4-byte units after the initial 32 bytes.
evtype
    XI-specific event type.
deviceid
    Numerical device id for a device.
time
    Time in ms.
┌───
    HierarchyEvent:
        EVENTHEADER
        flags:                      SETofHIERARCHYMASK
        num_info:                   CARD16
        info:                       LISTofHIERARCHYINFO
└───
HIERARCHYMASK { MasterAdded, MasterRemoved, SlaveAttached, SlaveDetached,
                SlaveAdded, SlaveRemoved, DeviceEnabled, DeviceDisabled }
HIERARCHYINFO { deviceid:           DEVICEID,
                attachment:         DEVICEID,
                type:               DEVICEUSE
                enabled:            BOOL
                flags:              SETofHIERARCHYMASK}
flags
    Set of the changes that have occured, causing this event.
num_info
    The number of device info structs following the request.
info:
    The current hierarchy information.

An XIHierarchyEvent is sent whenever the device hierarchy been changed. The flags specify all types of hierarchy modifiations that have occured. For all devices, info details the hierarchy information after the modification of the hierarchy has occured. For each device specified with deviceid:

  • if type is MasterPointer or MasterKeyboard, attachment decribes the pairing of this device.

  • if type is SlavePointer or SlaveKeyboard, attachment describes the master device this device is attached to.

  • if type is FloatingSlave device, attachment is undefined.

    enabled
         True if the device is enabled and can send events. A disabled master
         device will not forward events from an attached, enabled slave
         device.

Note: Multiple devices may be affected in one hierarchy change, deviceid in an XIHierarchyEvent is always the first affected device. Clients should ignore deviceid and instead use the devices list.

┌───
    DeviceChangedEvent:
        EVENTHEADER
        reason:                CHANGEREASON
        source:                DEVICEID
        num_classes:           CARD16
        classes:               LISTofCLASS
└───
CHANGEREASON { SlaveSwitch, DeviceChange }

A DeviceChangeEvent is sent whenever a device changes it’s capabilities. This can happen either by a new slave device sending events through a master device, or by a physical device changing capabilities at runtime.

reason
    The reason for generating this event.
    If reason is SlaveSwitch, the slave device sending events through
    this device has changed and source specifies the new slave device.
    A SlaveSwitch reason can only occur on a master device.
    If reason is DeviceChange, the device itself has changed through
    other means (e.g. a physical device change) and source is
    the device itself.
source
    The source of the new classes.
num_classes
    Number of classes provided.
classes
    Details the available classes provided by the device.  The order the
    classes are provided in is undefined.

For a detailed description of classes, see the XIQueryDevice request.

┌───
    DeviceEvent:
        EVENTHEADER
        detail:                     CARD32
        root:                       Window
        event:                      Window
        child:                      Window
        root_x:                     FP1616
        root_y:                     FP1616
        event_x:                    FP1616
        event_y:                    FP1616
        buttons_len:                CARD16
        valuators_len:              CARD16
        sourceid:                   DEVICEID
        mods:                       MODIFIERINFO
        group:                      GROUPINFO
        flags:                      DEVICEEEVENTFLAGS
        buttons:                    SETofBUTTONMASK
        valuators:                  SETofVALUATORMASK
        axisvalues:                 LISTofFP3232
└───
BUTTONBIT { (1 << Button1), (1 << Button2), ... , (1 << ButtonN) }
VALUATORBIT { (1 << 1), ( 1 << 2), ... ( 1 << n) }
MODIFIERINFO  { base_mods:           CARD32,
                latched_mods:        CARD32,
                locked_mods:         CARD32,
                effective_mods:      CARD32}
GROUPINFO     { base_group:          CARD8,
                latched_group:       CARD8,
                locked_group:        CARD8,
                effective_group:     CARD8}
DEVICEEVENTFLAGS (all events): none
DEVICEEVENTFLAGS (key events only): { KeyRepeat }
DEVICEEVENTFLAGS (pointer events only): { PointerEmulated }

An XIDeviceEvent is generated whenever the logical state of a device changes in response to a button press, a button release, a motion, a key press or a key release. The event type may be one of KeyPress, KeyRelease, ButtonPress, ButtonRelease, Motion.

detail
    The button number or key code, or 0.
root
event
child
    The root window, event window or subwindow, respectively. See core
    protocol specification for more detail.
root_x
root_y
    The position of the pointer in screen coordinates (16.16 fixed point).
event_x
event_y
    The position of the pointer in screen coordinates relative to the
    event window (16.16 fixed point).
buttons_len
    The length of buttons in 4 byte units.
valuators_len
    The length of valuators in 4 byte units.
sourceid
    The source device that originally generated the event.
mods
    XKB modifier state before the event occured.
group
    XKB group state before the event.
buttons
    Button state before the event.
valuators
    Bitmask of valuators provided in axisvalues.
axisvalues
    Valuator data in device-native resolution.
flags
    Miscellaneous information about this event; the union of the
    common flag set and either the key or pointer flag set,
    depending on the event type.
    KeyRepeat means that this event is for repeating purposes, and
    the physical state of the key has not changed.  This is only
    valid for KeyPress events.
    PointerEmulated signals that the event has been emulated from another
    XI 2.x event for legacy client support, and that this event should
    be ignored if the client listens for these events.  This flag is
    set on scroll ButtonPress and RawButtonPress events (buttons 4, 5, 6
    and 7) if a smooth-scrolling event on the Rel Vert Scroll or
    Rel Horiz Scroll axes was also generated.

Modifier state in mods is detailed as follows:

base_mods
    XKB base modifier state.
latched_mods
    XKB latched modifier state.
locked_mods
    XKB locked modifier state.
Group state in group is detailed as follows:
base_group
    XKB base group state.
latched_group
    XKB latched group state.
locked_group
    XKB locked group state.
┌───
    RawEvent
        EVENTHEADER
        detail:                    CARD32
        sourceid*:                 DEVICEID
        flags:                     DEVICEEVENTFLAGS
        valuators_len:             CARD16
        valuators:                 SETofVALUATORMASK
        axisvalues:                LISTofFP3232
        axisvalues_raw:            LISTofFP3232
└───
  • since XI 2.1

A RawEvent provides the information provided by the driver to the client. RawEvent provides both the raw data as supplied by the driver and transformed data as used in the server. Transformations include, but are not limited to, axis clipping and acceleration. Transformed valuator data may be equivalent to raw data. In this case, both raw and transformed valuator data is provided. RawEvents are sent exclusively to all root windows. Clients supporting XI 2.0 receive raw events when the device is not grabbed, or when the device is grabbed by the client but not when the device is grabbed by another client. Clients supporting XI 2.1 or later receive raw events at all times, even when the device is grabbed by another client.

eventtype
    The type of event that occured on the device.
detail
    The button number or keycode.
sourceid
    The source device that originally generated the event. The sourceid
    is undefined for clients not supporting XI 2.1.
flags
    Flags as described in DeviceEvent.
valuators_len
    The length of valuators in 4 byte units.
valuators
    Bitmask of valuators provided in axisvalues and axisvalues_raw.
axisvalues
    Valuator data in device-native resolution.
axisvalues_raw
    Untransformed valuator data in device-native resolution.
┌───
    Enter or Leave or FocusIn or FocusOut
        EVENTHEADER
        root:               Window
        event:              Window
        child:              Window
        sourceid:           DEVICEID
        root_x:             FP1616
        root_y:             FP1616
        event_x             FP1616
        event_y:            FP1616
        mode:               NOTIFYMODE
        detail:             NOTIFYDETAIL
        same_screen:        BOOL
        focus:              BOOL
        mods:               MODIFIERINFO
        group:              GROUPINFO
        buttons_len:        CARD16
        buttons:            SETofBUTTONMASK
└───
NOTIFYMODE { Normal, Grab, Ungrab }
NOTIFYDETAIL { Ancestor, Virtual, Inferior, Nonlinear, NonlinearVirtual,
               Pointer, PointerRoot, None }

Enter or Leave events are sent whenever a device’s pointer enters or leaves a window. FocusIn or FocusOut events are sent whenever a device’s focus is set to or away from a window. The enter/leave and focus in/out model is described in the core protocol specification, Section 11. (EnterNotify, LeaveNotify events).

For enter and leave events, the modifier and group state is the state of the paired master device if the device is a master device, or the state of the attached master keyboard if the device is an attached slave device, or zero if the device is a floating slave device.

For focus in and out events, the button state is the state of the paired master device if the device is a master device, or the state of the attached master keyboard if the device is an attached slave device, or zero if the device is a floating slave device.

root
event
child
    The root window, event window, and child window, respectively. See the
    core protocol specification for more detail.
sourceid
    The device that caused the pointer to move.
root_x
root_y
    The pointer coordinates relative to the root window.
event_x
event_y
    The pointer coordinates relative to the event window.
mode
    Normal pointer motion events have mode Normal. Pseudo-motion events
    when a grab activates have mode Grab, and pseudo-motion events when a
    grab deactivates have mode Ungrab. Pseudo-motion events caused by the
    activation or deactivation of a passive enter or focus in grab have mode
    XIPassiveGrabNotify or XIPassiveUngrabNotify.
detail
    Specifies the relation of the event window to the window the pointer
    entered or left. See the core protocol spec for details.
same_screen
    True if the event window is on the same screen as the pointer's root
    window.
focus
    If the event window is the focus window or an inferior of the focus
    window, then focus is True. Otherwise, focus is False. This field is
    unspecified for focus in/out events.
mods
    XKB modifier state before the event occured.
group
    XKB group state before the event.
buttons_len
    The length of buttons in 4 byte units.
buttons
    Button state before the event.
┌───
    XIPropertyEvent
        EVENTHEADER
        property:           ATOM
        what:               { PropertyCreated, PropertyDeleted, PropertyModified }
└───

XIPropertyEvents are sent whenever a device property is created, deleted or modified by a client.

property
    The property that has been created, deleted, or modified
what
    Specifies what has been changed.