Fractional scale

Protocol for requesting fractional surface scales

This protocol allows a compositor to suggest for surfaces to render at fractional scales.

A client can submit scaled content by utilizing wp_viewport. This is done by creating a wp_viewport object for the surface and setting the destination rectangle to the surface size before the scale factor is applied.

The buffer size is calculated by multiplying the surface size by the intended scale.

The wl_surface buffer scale should remain set to 1.

If a surface has a surface-local size of 100 px by 50 px and wishes to submit buffers with a scale of 1.5, then a buffer of 150px by 75 px should be used and the wp_viewport destination rectangle should be 100 px by 50 px.

For toplevel surfaces, the size is rounded halfway away from zero. The rounding algorithm for subsurface position and size is not defined.

wp_fractional_scale_manager_v1

version 1

fractional surface scale information

A global interface for requesting surfaces to use fractional scales.

wp_fractional_scale_manager_v1::destroy

Type: destructor

destroy()

unbind the fractional surface scale interface

Informs the server that the client will not be using this protocol object anymore. This does not affect any other objects, wp_fractional_scale_v1 objects included.

wp_fractional_scale_manager_v1::get_fractional_scale

get_fractional_scale(id: new_id<wp_fractional_scale_v1>, surface: object<wl_surface>)

Argument	Type	Description
id	new_id<wp_fractional_scale_v1>	the new surface scale info interface id
surface	object<wl_surface>	the surface

extend surface interface for scale information

Create an add-on object for the the wl_surface to let the compositor request fractional scales. If the given wl_surface already has a wp_fractional_scale_v1 object associated, the fractional_scale_exists protocol error is raised.

wp_fractional_scale_manager_v1::error

error { fractional_scale_exists }

Argument	Value	Description
fractional_scale_exists	0	the surface already has a fractional_scale object associated

wp_fractional_scale_v1

version 1

fractional scale interface to a wl_surface

An additional interface to a wl_surface object which allows the compositor to inform the client of the preferred scale.

wp_fractional_scale_v1::destroy

Type: destructor

destroy()

remove surface scale information for surface

Destroy the fractional scale object. When this object is destroyed, preferred_scale events will no longer be sent.

wp_fractional_scale_v1::preferred_scale

preferred_scale(scale: uint)

Argument	Type	Description
scale	uint	the new preferred scale

notify of new preferred scale

Notification of a new preferred scale for this surface that the compositor suggests that the client should use.

The sent scale is the numerator of a fraction with a denominator of 120.

Compositor Support

	Mutter 46	KWin 6.2	Sway 1.9	COSMIC 1.0.0	Hyprland 0.42.0	niri 0.1.8	Weston 13	Mir 2.18	GameScope 3.15.14	Jay 1.7.0
wp_fractional_scale_manager_v1	1	1	1	1	1	1	x	1	x	1

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