KDE output device

Output configuration representation

An outputdevice describes a display device available to the compositor. outputdevice is similar to wl_output, but focuses on output configuration management.

A client can query all global outputdevice objects to enlist all available display devices, even those that may currently not be represented by the compositor as a wl_output.

The client sends configuration changes to the server through the outputconfiguration interface, and the server applies the configuration changes to the hardware and signals changes to the outputdevices accordingly.

This object is published as global during start up for every available display devices, or when one later becomes available, for example by being hotplugged via a physical connector.

geometry(x: int, y: int, physical_width: int, physical_height: int, subpixel: int, make: string, model: string, transform: int)
Argument
Type
Description
xint
x position within the global compositor space
yint
y position within the global compositor space
physical_widthint
width in millimeters of the output
physical_heightint
height in millimeters of the output
subpixelint
subpixel orientation of the output
makestring
textual description of the manufacturer
modelstring
textual description of the model
transformint
transform that maps framebuffer to output
Geometric properties of the output

The geometry event describes geometric properties of the output. The event is sent when binding to the output object and whenever any of the properties change.

mode(flags: uint, width: int, height: int, refresh: int, mode_id: int)
Argument
Type
Description
flagsuint
bitfield of mode flags
widthint
width of the mode in hardware units
heightint
height of the mode in hardware units
refreshint
vertical refresh rate in mHz
mode_idint
Per outputdevice unique id to identify a mode
Advertise available output modes and current one

The mode event describes an available mode for the output.

When the client binds to the outputdevice object, the server sends this event once for every available mode the outputdevice can be operated by.

There will always be at least one event sent out on initial binding, which represents the current mode.

Later on if an output changes its mode the event is sent again, whereby this event represents the mode that has now become current. In other words, the current mode is always represented by the latest event sent with the current flag set.

The size of a mode is given in physical hardware units of the output device. This is not necessarily the same as the output size in the global compositor space. For instance, the output may be scaled, as described in org_kde_kwin_outputdevice.scale, or transformed, as described in org_kde_kwin_outputdevice.transform.

The id can be used to refer to a mode when calling set_mode on an org_kde_kwin_outputconfiguration object.

done()
Sent all information about output

This event is sent after all other properties have been sent on binding to the output object as well as after any other output property change have been applied later on. This allows to see changes to the output properties as atomic, even if multiple events successively announce them.

scale(factor: int)
Argument
Type
Description
factorint
scaling factor of output
Output scaling properties

This event contains scaling geometry information that is not in the geometry event. It may be sent after binding the output object or if the output scale changes later. If it is not sent, the client should assume a scale of 1.

A scale larger than 1 means that the compositor will automatically scale surface buffers by this amount when rendering. This is used for high resolution displays where applications rendering at the native resolution would be too small to be legible.

It is intended that scaling aware clients track the current output of a surface, and if it is on a scaled output it should use wl_surface.set_buffer_scale with the scale of the output. That way the compositor can avoid scaling the surface, and the client can supply a higher detail image.

edid(raw: string)
Argument
Type
Description
rawstring
base64-encoded EDID string
Advertise EDID data for the output

The edid event encapsulates the EDID data for the outputdevice.

The event is sent when binding to the output object. The EDID data may be empty, in which case this event is sent anyway. If the EDID information is empty, you can fall back to the name et al. properties of the outputdevice.

enabled(enabled: int)
Argument
Type
Description
enabledint
output enabled state
Output is enabled or disabled

The enabled event notifies whether this output is currently enabled and used for displaying content by the server. The event is sent when binding to the output object and whenever later on an output changes its state by becoming enabled or disabled.

uuid(uuid: string)
Argument
Type
Description
uuidstring
output devices ID
A unique id for this outputdevice

The uuid can be used to identify the output. It's controlled by the server entirely. The server should make sure the uuid is persistent across restarts. An empty uuid is considered invalid.

scalef(factor: fixed)
Argument
Type
Description
factorfixed
scaling factor of output
Output scaling properties

This event contains scaling geometry information that is not in the geometry event. It may be sent after binding the output object or if the output scale changes later. If it is not sent, the client should assume a scale of 1.

A scale larger than 1 means that the compositor will automatically scale surface buffers by this amount when rendering. This is used for high resolution displays where applications rendering at the native resolution would be too small to be legible.

It is intended that scaling aware clients track the current output of a surface, and if it is on a scaled output it should use wl_surface.set_buffer_scale with the scale of the output. That way the compositor can avoid scaling the surface, and the client can supply a higher detail image.

wl_output will keep the output scale as an integer. In every situation except configuring the window manager you want to use that.

colorcurves(red: array, green: array, blue: array)
Argument
Type
Description
redarray
red color ramp
greenarray
green color ramp
bluearray
blue color ramp
Output color curves

Describes the color intensity profile of the output. Commonly used for gamma/color correction.

The array contains all color ramp values of the output. For example on 8bit screens there are 256 of them.

The array elements are unsigned 16bit integers.

serial_number(serialNumber: string)
Argument
Type
Description
serialNumberstring
textual representation of serial number
Serial Number

Serial ID of the monitor, sent on startup before the first done event.

eisa_id(eisaId: string)
Argument
Type
Description
eisaIdstring
textual representation of EISA identifier
EISA ID

EISA ID of the monitor, sent on startup before the first done event.

Argument
Type
Description
flagsuint<org_kde_kwin_outputdevice.capability>
Capability flags

What capabilities this device has, sent on startup before the first done event.

overscan(overscan: uint)
Argument
Type
Description
overscanuint
amount of overscan of the monitor
Overscan

Overscan value of the monitor in percent, sent on startup before the first done event.

Variable Refresh Rate Policy

What policy the compositor will employ regarding its use of variable refresh rate.

Subpixel geometry information

This enumeration describes how the physical pixels on an output are laid out.

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 rotation.

The purpose is mainly to allow clients to render accordingly and tell the compositor, so that for fullscreen surfaces, the compositor is still able to scan out directly client surfaces.

mode { current, preferred } 
Argument
Value
Description
current0x1
indicates this is the current mode
preferred0x2
indicates this is the preferred mode
Mode information

These flags describe properties of an output mode. They are used in the flags bitfield of the mode event.

enablement { disabled, enabled } 
Argument
Value
Description
disabled0
enabled1
Describes enabled state

Describes whether a device is enabled, i.e. device is used to display content by the compositor. This wraps a boolean around an int to avoid a boolean trap.

capability { overscan, vrr } 
Argument
Value
Description
overscan1
if this outputdevice can use overscan
vrrsince 42
if this outputdevice supports variable refresh rate
Describes capabilities of the outputdevice

Describes what capabilities this device has.

vrr_policy { never, always, automatic } 
Argument
Value
Description
never0
always1
automatic2
Describes vrr policy

Describes when the compositor may employ variable refresh rate


SPDX-FileCopyrightText: 2008-2011 Kristian Høgsberg SPDX-FileCopyrightText: 2010-2011 Intel Corporation SPDX-FileCopyrightText: 2012-2013 Collabora, Ltd. SPDX-FileCopyrightText: 2015 Sebastian Kügler <sebas@kde.org>

SPDX-License-Identifier: MIT-CMU