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Wayland Protocol Specification

Table of Contents

wl_display - core global object

Version: 1

The core global object. This is a special singleton object. It is used for internal wayland protocol features.

Requests

wl_display::bind - bind an object to the display

Binds a new, client-created object to the server using @name as the identifier.

Arguments:
name uint unique number id for object
interface string
version uint
id new_id

wl_display::sync - asynchronous roundtrip

The sync request asks the server to invoke the 'done' request on the provided wl_callback object. Since requests are handled in-order, this can be used as a barrier to ensure all previous requests have been handled.

Arguments:
callback new_id

Events

wl_display::error - fatal error event

The error event is sent out when a fatal (non-recoverable) error has occurred.

Arguments:
object_id object
code uint
message string

wl_display::global - announce global object

Notify the client of global objects. These are objects that are created by the server. Globals are published on the initial client connection sequence, upon device hotplugs, device disconnects, reconfiguration or other events. A client can 'bind' to a global object by using the bind request. This creates a client side handle that lets the object emit events to the client and lets the client invoke requests on the object.

Arguments:
name uint
interface string
version uint

wl_display::global_remove - announce removal of global object

Notify the client of removed global objects.

Arguments:
name uint

wl_display::delete_id - acknowledge object id deletion

Server has deleted the id and client can now reuse it.

Arguments:
id uint

Enums

wl_display::error - global error values

These errors are global and can be emitted in response to any server request.

Values:
invalid_object 0 server couldn't find object
invalid_method 1 method doesn't exist on the specified interface
no_memory 2 server is out of memory

wl_callback

Version: 1

Events

wl_callback::done

Arguments:
serial uint

wl_compositor - the compositor singleton

Version: 1

A compositor. This object is a singleton global. The compositor is in charge of combining the contents of multiple surfaces into one displayable output.

Requests

wl_compositor::create_surface - create new surface

Ask the compositor to create a new surface.

Arguments:
id new_id

wl_compositor::create_region - create new region

Ask the compositor to create a new region.

Arguments:
id new_id

wl_shm_pool - a shared memory pool

Version: 1

The wl_shm_pool object encapsulates a piece of memory shared between the compsitor and client. Through the wl_shm_pool object, the client can allocate shared memory wl_buffer objects. The objects will share the same underlying mapped memory. Reusing the mapped memory avoids the setup/teardown overhead and is useful when interactively resizing a surface or for many small buffers.

Requests

wl_shm_pool::create_buffer - create wl_buffer from pool

Create a wl_buffer from the pool. The buffer is created a offset bytes into the pool and has width and height as specified. The stride arguments specifies the number of bytes from beginning of one row to the beginning of the next. The format is the pixel format of the buffer and must be one of those advertised through the wl_shm.format event. A buffer will keep a reference to the pool it was created from so it is valid to destroy the pool immediatedly after creating a buffer from it.

Arguments:
id new_id
offset int
width int
height int
stride int
format uint

wl_shm_pool::destroy - destroy the pool

Destroy the pool.

wl_shm_pool::resize - change the size of the pool mapping

This request will cause the server to remap the backing memory for the pool from the fd passed when the pool was creating but using the new size.

Arguments:
size int

wl_shm - shared memory support

Version: 1

Support for shared memory buffers.

Requests

wl_shm::create_pool - create a shm pool

This creates wl_shm_pool object, which can be used to create shared memory based wl_buffer objects. The server will mmap size bytes of the passed fd, to use as backing memory for then pool.

Arguments:
id new_id
fd fd
size int

Events

wl_shm::format

Arguments:
format uint

Enums

wl_shm::error

Values:
invalid_format 0
invalid_stride 1
invalid_fd 2

wl_shm::format

Values:
argb8888 0
xrgb8888 1

wl_buffer - content for a wl_surface

Version: 1

A buffer provides the content for a wl_surface. Buffers are created through factory interfaces such as wl_drm, wl_shm or similar. It has a width and a height and can be attached to a wl_surface, but the mechanism by which a client provides and updates the contents is defined by the buffer factory interface

Requests

wl_buffer::destroy - destroy a buffer

Destroy a buffer. This will invalidate the object id.

Events

wl_buffer::release - compositor releases buffer

Sent when an attached buffer is no longer used by the compositor.

wl_data_offer

Version: 1

Requests

wl_data_offer::accept - accept one of the offered mime-types

Indicate that the client can accept the given mime-type, or NULL for not accepted. Use for feedback during drag and drop.

Arguments:
serial uint
type string

wl_data_offer::receive

Arguments:
mime_type string
fd fd

wl_data_offer::destroy

Events

wl_data_offer::offer - advertise offered mime-type

Sent immediately after creating the wl_data_offer object. One event per offered mime type.

Arguments:
type string

wl_data_source

Version: 1

Requests

wl_data_source::offer - add an offered mime type

This request adds a mime-type to the set of mime-types advertised to targets. Can be called several times to offer multiple types.

Arguments:
type string

wl_data_source::destroy - destroy the data source

Destroy the data source.

Events

wl_data_source::target - a target accepts an offered mime-type

Sent when a target accepts pointer_focus or motion events. If a target does not accept any of the offered types, type is NULL.

Arguments:
mime_type string

wl_data_source::send - send the data

Request for data from another client. Send the data as the specified mime-type over the passed fd, then close the fd.

Arguments:
mime_type string
fd fd

wl_data_source::cancelled - selection was cancelled

Another selection became active.

wl_data_device

Version: 1

Requests

wl_data_device::start_drag - start drag and drop operation

This request asks the compositor to start a drag and drop operation on behalf of the client. The source argument is the data source that provides the data for the eventual data transfer. If source is NULL, enter, leave and motion events are sent only to the client that initiated the drag and the client is expected to handle the data passing internally. The origin surface is the surface where the drag originates and the client must have an active implicit grab that matches the serial. The icon surface is an optional (can be nil) surface that provides an icon to be moved around with the cursor. Initially, the top-left corner of the icon surface is placed at the cursor hotspot, but subsequent surface.attach request can move the relative position.

Arguments:
source object
origin object
icon object
serial uint

wl_data_device::set_selection

Arguments:
source object
serial uint

Events

wl_data_device::data_offer - introduce a new wl_data_offer

The data_offer event introduces a new wl_data_offer object, which will subsequently be used in either the data_device.enter event (for drag and drop) or the data_device.selection event (for selections). Immediately following the data_device_data_offer event, the new data_offer object will send out data_offer.offer events to describe the mime-types it offers.

Arguments:
id new_id

wl_data_device::enter

Arguments:
serial uint
surface object
x fixed
y fixed
id object

wl_data_device::leave

wl_data_device::motion

Arguments:
time uint
x fixed
y fixed

wl_data_device::drop

wl_data_device::selection - advertise new selection

The selection event is sent out to notify the client of a new wl_data_offer for the selection for this device. The data_device.data_offer and the data_offer.offer events are sent out immediately before this event to introduce the data offer object. The selection event is sent to a client immediately before receiving keyboard focus and when a new selection is set while the client has keyboard focus. The data_offer is valid until a new data_offer or NULL is received or until the client loses keyboard focus.

Arguments:
id object

wl_data_device_manager

Version: 1

Requests

wl_data_device_manager::create_data_source

Arguments:
id new_id

wl_data_device_manager::get_data_device

Arguments:
id new_id
seat object

wl_shell

Version: 1

Requests

wl_shell::get_shell_surface

Arguments:
id new_id
surface object

wl_shell_surface - desktop style meta data interface

Version: 1

An interface implemented by a wl_surface. On server side the object is automatically destroyed when the related wl_surface is destroyed. On client side, wl_shell_surface_destroy() must be called before destroying the wl_surface object.

Requests

wl_shell_surface::pong - respond to a ping event

A client must respond to a ping event with a pong request or the client may be deemed unresponsive.

Arguments:
serial uint

wl_shell_surface::move

Arguments:
seat object
serial uint

wl_shell_surface::resize

Arguments:
seat object
serial uint
edges uint

wl_shell_surface::set_toplevel - make the surface a top level surface

Make the surface a toplevel window.

wl_shell_surface::set_transient - make the surface a transient surface

Map the surface relative to an existing surface. The x and y arguments specify the locations of the upper left corner of the surface relative to the upper left corner of the parent surface. The flags argument controls overflow/clipping behaviour when the surface would intersect a screen edge, panel or such. And possibly whether the offset only determines the initial position or if the surface is locked to that relative position during moves.

Arguments:
parent object
x int
y int
flags uint

wl_shell_surface::set_fullscreen - make the surface a fullscreen surface

Map the surface as a fullscreen surface. If an output parameter is given then the surface will be made fullscreen on that output. If the client does not specify the output then the compositor will apply its policy - usually choosing the output on which the surface has the biggest surface area. The client may specify a method to resolve a size conflict between the output size and the surface size - this is provided through the fullscreen_method parameter. The framerate parameter is used only when the fullscreen_method is set to "driver", to indicate the preferred framerate. framerate=0 indicates that the app does not care about framerate. The framerate is specified in mHz, that is framerate of 60000 is 60Hz. The compositor must reply to this request with a configure event with the dimensions for the output on which the surface will be made fullscreen.

Arguments:
method uint
framerate uint
output object

wl_shell_surface::set_popup - make the surface a popup surface

Popup surfaces. Will switch an implicit grab into owner-events mode, and grab will continue after the implicit grab ends (button released). Once the implicit grab is over, the popup grab continues until the window is destroyed or a mouse button is pressed in any other clients window. A click in any of the clients surfaces is reported as normal, however, clicks in other clients surfaces will be discarded and trigger the callback. TODO: Grab keyboard too, maybe just terminate on any click inside or outside the surface?

Arguments:
seat object
serial uint
parent object
x int
y int
flags uint

wl_shell_surface::set_maximized - make the surface a maximized surface

A request from the client to notify the compositor the maximized operation. The compositor will reply with a configure event telling the expected new surface size. The operation is completed on the next buffer attach to this surface. A maximized client will fill the fullscreen of the output it is bound to, except the panel area. This is the main difference between a maximized shell surface and a fullscreen shell surface.

Arguments:
output object

wl_shell_surface::set_title - set surface title

Arguments:
title string

wl_shell_surface::set_class - set surface class

The surface class identifies the general class of applications to which the surface belongs. The class is the file name of the applications .desktop file (absolute path if non-standard location).

Arguments:
class_ string

Events

wl_shell_surface::ping - ping client

Ping a client to check if it is receiving events and sending requests. A client is expected to reply with a pong request.

Arguments:
serial uint

wl_shell_surface::configure - suggest resize

The configure event asks the client to resize its surface. The size is a hint, in the sense that the client is free to ignore it if it doesn't resize, pick a smaller size (to satisfy aspect ration or resize in steps of NxM pixels). The client is free to dismiss all but the last configure event it received.

Arguments:
edges uint
width int
height int

wl_shell_surface::popup_done - popup interaction is done

The popup_done event is sent out when a popup grab is broken, that is, when the users clicks a surface that doesn't belong to the client owning the popup surface.

Enums

wl_shell_surface::resize

Values:
none 0
top 1
bottom 2
left 4
top_left 5
bottom_left 6
right 8
top_right 9
bottom_right 10

wl_shell_surface::transient

Values:
inactive 0x1 do not set keyboard focus

wl_shell_surface::fullscreen_method - different method to set the surface fullscreen

Hints to indicate compositor how to deal with a conflict between the dimensions for the surface and the dimensions of the output. As a hint the compositor is free to ignore this parameter. "default" The client has no preference on fullscreen behavior, policies are determined by compositor. "scale" The client prefers scaling by the compositor. Scaling would always preserve surface's aspect ratio with surface centered on the output "driver" The client wants to switch video mode to the smallest mode that can fit the client buffer. If the sizes do not match the compositor must add black borders. "fill" The surface is centered on the output on the screen with no scaling. If the surface is of insufficient size the compositor must add black borders.

Values:
default 0
scale 1
driver 2
fill 3

wl_surface - an onscreen surface

Version: 1

A surface. This is an image that is displayed on the screen. It has a location, size and pixel contents.

Requests

wl_surface::destroy - delete surface

Deletes the surface and invalidates its object id.

wl_surface::attach - set the surface contents

Copy the contents of a buffer into this surface. The x and y arguments specify the location of the new buffers upper left corner, relative to the old buffers upper left corner.

Arguments:
buffer object
x int
y int

wl_surface::damage - mark part of the surface damaged

After attaching a new buffer, this request is used to describe the regions where the new buffer is different from the previous buffer and needs to be repainted. Coordinates are relative to the new buffer.

Arguments:
x int
y int
width int
height int

wl_surface::frame - request repaint feedback

Request notification when the next frame is displayed. Useful for throttling redrawing operations, and driving animations. The notification will only be posted for one frame unless requested again.

Arguments:
callback new_id

wl_surface::set_opaque_region - set opaque region

This requests sets the region of the surface that contain opaque content. The opaque region is an optimization hint for the compositor that lets it optimize out redrawing of content behind opaque regions. Setting an opaque region is not required for correct behaviour, but marking transparent content as opaque will result in repaint artifacts. The region will be clipped to the extents of the current surface size. Setting the region has copy semantics, and the region object can be destroyed immediately after setting the opaque region. If a buffer of a different size is attached or if a nil region is set, the opaque region will revert back to default. The default opaque region is empty.

Arguments:
region object

wl_surface::set_input_region - set input region

This requests sets the region of the surface that can receive pointer and touch events. The region will be clipped to the extents of the current surface size. Setting the region has copy semantics, and the region object can be destroyed immediately after setting the input region. If a buffer of a different size is attached or if a nil region is passed, the input region will revert back to default. The default input region is the entire surface.

Arguments:
region object

Events

wl_surface::enter - surface enters an output

This is emitted whenever a surface's creation, movement, or resizing results in some part of it being within the scanout region of an output.

Arguments:
output object

wl_surface::leave - surface leaves an output

This is emitted whenever a surface's creation, movement, or resizing results in it no longer having any part of it within the scanout region of an output.

Arguments:
output object

wl_seat - seat

Version: 1

A group of keyboards, pointer (mice, for example) and touch devices . This object is published as a global during start up, or when such a device is hot plugged. A seat typically has a pointer and maintains a keyboard_focus and a pointer_focus.

Requests

wl_seat::get_pointer - return pointer object

The ID provided will be initialized to the wl_pointer interface for this seat.

Arguments:
id new_id

wl_seat::get_keyboard - return pointer object

The ID provided will be initialized to the wl_keyboard interface for this seat.

Arguments:
id new_id

wl_seat::get_touch - return pointer object

The ID provided will be initialized to the wl_touch interface for this seat.

Arguments:
id new_id

Events

wl_seat::capabilities - seat capabilities changed

This is emitted whenever a seat gains or loses the pointer, keyboard or touch capabilities. The argument is a wl_seat_caps_mask enum containing the complete set of capabilities this seat has.

Arguments:
capabilities uint

Enums

wl_seat::capability - seat capability bitmask

This is a bitmask of capabilities this seat has; if a member is set, then it is present on the seat.

Values:
pointer 1 wl_pointer
keyboard 2 wl_keyboard
touch 4 wl_touch

wl_pointer

Version: 1

Requests

wl_pointer::set_cursor - set the pointer surface

Set the pointer surface, i.e., the surface that contains the pointer image. This request only takes effect if the pointer focus for this device is one of the requesting client surfaces or the surface parameter is the current pointer surface. If there was a previous surface set with this request it is replaced. If surface is NULL, the pointer image is hidden. The parameters hotspot_x and hotspot_y define the position of the pointer surface relative to the pointer location. Its top-left corner is always at (x, y) - (hotspot_x, hotspot_y), where (x, y) are the coordinates of the pointer location. On surface.attach requests to the pointer surface, hotspot_x and hotspot_y are decremented by the x and y parameters passed to the request. The hotspot can also be updated by passing the current set pointer surface to this request with new values for hotspot_x and/or hotspot_y.

Arguments:
serial uint
surface object
hotspot_x int
hotspot_y int

Events

wl_pointer::enter - enter event

Notification that this seat's pointer is focused on a certain surface. When an seat's focus enters a surface, the pointer image is undefined and a client should respond to this event by setting an appropriate pointer image.

Arguments:
serial uint
surface object
surface_x fixed
surface_y fixed

wl_pointer::leave - leave event

Arguments:
serial uint
surface object

wl_pointer::motion - pointer motion event

Notification of pointer location change. The arguments surface_[xy] are the location relative to the focused surface.

Arguments:
time uint
surface_x fixed
surface_y fixed

wl_pointer::button - pointer button event

Mouse button click and release notifications. The location of the click is given by the last motion or pointer_focus event.

Arguments:
serial uint
time uint
button uint
state uint

wl_pointer::axis - axis event

Scroll and other axis notifications.

Arguments:
time uint
axis uint
value fixed

Enums

wl_pointer::button_state - physical button state

Describes the physical state of a button which provoked the button event.

Values:
released 0 button is not pressed
pressed 1 button is pressed

wl_pointer::axis - axis types

Values:
vertical_scroll 0
horizontal_scroll 1

wl_keyboard - keyboard input device

Version: 1

Events

wl_keyboard::keymap - keyboard mapping

This event provides a file descriptor to the client which can be memory-mapped to provide a keyboard mapping description.

Arguments:
format uint
fd fd
size uint

wl_keyboard::enter

Arguments:
serial uint
surface object
keys array

wl_keyboard::leave

Arguments:
serial uint
surface object

wl_keyboard::key - key event

A key was pressed or released.

Arguments:
serial uint
time uint
key uint
state uint

wl_keyboard::modifiers - modifier and group state

Notifies clients that the modifier and/or group state has changed, and it should update its local state.

Arguments:
serial uint
mods_depressed uint
mods_latched uint
mods_locked uint
group uint

Enums

wl_keyboard::keymap_format - keyboard mapping format

This enum specifies the format of the keymap provided to the client with the wl_keyboard::keymap event.

Values:
xkb_v1 1

wl_keyboard::key_state - physical key state

Describes the physical state of a key which provoked the key event. When a key repeats, the sequence is down -> repeat -> repeat -> up.

Values:
released 0 key is not pressed
pressed 1 key is pressed
repeat 2 key is pressed and repeating

wl_touch - touch screen input device

Version: 1

Events

wl_touch::down

Arguments:
serial uint
time uint
surface object
id int
x fixed
y fixed

wl_touch::up

Arguments:
serial uint
time uint
id int

wl_touch::motion

Arguments:
time uint
id int
x fixed
y fixed

wl_touch::frame - end of touch frame event

Indicates the end of a contact point list.

wl_touch::cancel - touch session cancelled

Sent if the compositor decides the touch stream is a global gesture. No further events are sent to the clients from that particular gesture.

wl_output - compositor output region

Version: 1

An output describes part of the compositor geometry. The compositor work in the 'compositor coordinate system' and an output corresponds to rectangular area in that space that is actually visible. This typically corresponds to a monitor that displays part of the compositor space. This object is published as global during start up, or when a screen is hot plugged.

Events

wl_output::geometry - properties of the output

Arguments:
x int x position within the global compositor space
y int y position within the global compositor space
physical_width int width in millimeters of the output
physical_height int height in millimeters of the output
subpixel int subpixel orientation of the output
make string textual description of the manufacturer
model string textual description of the model
transform int transform that maps framebuffer to output

wl_output::mode - advertise available modes for the output

The mode event describes an available mode for the output. The event is sent when binding to the output object and there will always be one mode, the current mode. The event is sent again if an output changes mode, for the mode that is now current. In other words, the current mode is always the last mode that was received with the current flag set.

Arguments:
flags uint mask of wl_output_mode flags
width int width of the mode in pixels
height int height of the mode in pixels
refresh int vertical refresh rate in mHz

Enums

wl_output::subpixel

Values:
unknown 0
none 1
horizontal_rgb 2
horizontal_bgr 3
vertical_rgb 4
vertical_bgr 5

wl_output::transform - transform from framebuffer to output

This describes the transform that a compositor will apply to a surface to compensate for the rotation or mirroring of an output device. The flipped values correspond to an initial flip around a vertical axis followed by rotaion. The purpose is mainly to allow clients render accordingly and tell the compositor, so that for fullscreen surfaces, the compositor will still be able to scan out directly from client surfaces.

Values:
normal 0
90 1
180 2
270 3
flipped 4
flipped_90 5
flipped_180 6
flipped_270 7

wl_output::mode - values for the flags bitfield in the mode event

Values:
current 0x1 indicates this is the current mode
preferred 0x2 indicates this is the preferred mode

wl_region - region interface

Version: 1

Region.

Requests

wl_region::destroy - destroy region

Destroy the region. This will invalidate the object id.

wl_region::add - add rectangle to region

Add the specified rectangle to the region

Arguments:
x int
y int
width int
height int

wl_region::subtract - subtract rectangle from region

Subtract the specified rectangle from the region

Arguments:
x int
y int
width int
height int