Package org.freedesktop.wayland.server

Class WlTouchResource

java.lang.Object

org.freedesktop.wayland.server.Resource<WlTouchRequests>

org.freedesktop.wayland.server.WlTouchResource

All Implemented Interfaces:

WaylandObject

public class WlTouchResource
extends Resource<WlTouchRequests>

touchscreen input device

The wl_touch interface represents a touchscreen associated with a seat.

Touch interactions can consist of one or more contacts. For each contact, a series of events is generated, starting with a down event, followed by zero or more motion events, and ending with an up event. Events relating to the same contact point can be identified by the ID of the sequence.

Field Summary

Fields

Modifier and Type	Field	Description
static final String	INTERFACE_NAME

Fields inherited from class org.freedesktop.wayland.server.Resource

wlResourcePtr

Constructor Summary

Constructors

Constructor	Description
WlTouchResource(MemorySegment pointer)
WlTouchResource(Client client, int version, int id, WlTouchRequests implementation)

Method Summary

Modifier and Type	Method	Description
void	cancel()	touch session cancelled
void	down(int serial, int time, WlSurfaceResource surface, int id, Fixed x, Fixed y)	touch down event and beginning of a touch sequence
void	frame()	end of touch frame event
void	motion(int time, int id, Fixed x, Fixed y)	update of touch point coordinates
void	orientation(int id, Fixed orientation)	update orientation of touch point
void	shape(int id, Fixed major, Fixed minor)	update shape of touch point
void	up(int serial, int time, int id)	end of a touch event sequence

Methods inherited from class org.freedesktop.wayland.server.Resource

addDestroyListener, destroy, equals, getClient, getId, getImplementation, getPointer, getVersion, hashCode, postError, postEvent, postEvent, register, unregister

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, toString, wait, wait, wait

Field Details

INTERFACE_NAME

public static final String INTERFACE_NAME

See Also:

• Constant Field Values

Constructor Details

WlTouchResource

public WlTouchResource(Client client,
 int version,
 int id,
 WlTouchRequests implementation)

WlTouchResource

public WlTouchResource(MemorySegment pointer)

Method Details

down

public void down(int serial,
 int time,
 @Nonnull
 WlSurfaceResource surface,
 int id,
 @Nonnull
 Fixed x,
 @Nonnull
 Fixed y)

touch down event and beginning of a touch sequence

A new touch point has appeared on the surface. This touch point is assigned a unique ID. Future events from this touch point reference this ID. The ID ceases to be valid after a touch up event and may be reused in the future.

Parameters:

serial - serial number of the touch down event

time - timestamp with millisecond granularity

surface - surface touched

id - the unique ID of this touch point

x - surface-local x coordinate

y - surface-local y coordinate

up

public void up(int serial,
 int time,
 int id)

end of a touch event sequence

The touch point has disappeared. No further events will be sent for this touch point and the touch point's ID is released and may be reused in a future touch down event.

Parameters:

serial - serial number of the touch up event

time - timestamp with millisecond granularity

id - the unique ID of this touch point

motion

public void motion(int time,
 int id,
 @Nonnull
 Fixed x,
 @Nonnull
 Fixed y)

update of touch point coordinates

A touch point has changed coordinates.

Parameters:

time - timestamp with millisecond granularity

id - the unique ID of this touch point

x - surface-local x coordinate

y - surface-local y coordinate

frame

public void frame()

end of touch frame event

Indicates the end of a set of events that logically belong together. A client is expected to accumulate the data in all events within the frame before proceeding.

A wl_touch.frame terminates at least one event but otherwise no guarantee is provided about the set of events within a frame. A client must assume that any state not updated in a frame is unchanged from the previously known state.

cancel

public void 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. Touch cancellation applies to all touch points currently active on this client's surface. The client is responsible for finalizing the touch points, future touch points on this surface may reuse the touch point ID.

No frame event is required after the cancel event.

shape

public void shape(int id,
 @Nonnull
 Fixed major,
 @Nonnull
 Fixed minor)

update shape of touch point

Sent when a touchpoint has changed its shape.

This event does not occur on its own. It is sent before a wl_touch.frame event and carries the new shape information for any previously reported, or new touch points of that frame.

Other events describing the touch point such as wl_touch.down, wl_touch.motion or wl_touch.orientation may be sent within the same wl_touch.frame. A client should treat these events as a single logical touch point update. The order of wl_touch.shape, wl_touch.orientation and wl_touch.motion is not guaranteed. A wl_touch.down event is guaranteed to occur before the first wl_touch.shape event for this touch ID but both events may occur within the same wl_touch.frame.

A touchpoint shape is approximated by an ellipse through the major and minor axis length. The major axis length describes the longer diameter of the ellipse, while the minor axis length describes the shorter diameter. Major and minor are orthogonal and both are specified in surface-local coordinates. The center of the ellipse is always at the touchpoint location as reported by wl_touch.down or wl_touch.move.

This event is only sent by the compositor if the touch device supports shape reports. The client has to make reasonable assumptions about the shape if it did not receive this event.

Parameters:

id - the unique ID of this touch point

major - length of the major axis in surface-local coordinates

minor - length of the minor axis in surface-local coordinates

orientation

public void orientation(int id,
 @Nonnull
 Fixed orientation)

update orientation of touch point

Sent when a touchpoint has changed its orientation.

This event does not occur on its own. It is sent before a wl_touch.frame event and carries the new shape information for any previously reported, or new touch points of that frame.

Other events describing the touch point such as wl_touch.down, wl_touch.motion or wl_touch.shape may be sent within the same wl_touch.frame. A client should treat these events as a single logical touch point update. The order of wl_touch.shape, wl_touch.orientation and wl_touch.motion is not guaranteed. A wl_touch.down event is guaranteed to occur before the first wl_touch.orientation event for this touch ID but both events may occur within the same wl_touch.frame.

The orientation describes the clockwise angle of a touchpoint's major axis to the positive surface y-axis and is normalized to the -180 to +180 degree range. The granularity of orientation depends on the touch device, some devices only support binary rotation values between 0 and 90 degrees.

This event is only sent by the compositor if the touch device supports orientation reports.

Parameters:

id - the unique ID of this touch point

orientation - angle between major axis and positive surface y-axis in degrees