Copyright 2014 © Stephen "Lyude" Chandler Paul Copyright 2015-2016 © Red Hat, Inc. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice (including the next paragraph) shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. This description provides a high-level overview of the interplay between the interfaces defined this protocol. For details, see the protocol specification. More than one tablet may exist, and device-specifics matter. Tablets are not represented by a single virtual device like wl_pointer. A client binds to the tablet manager object which is just a proxy object. From that, the client requests wp_tablet_manager.get_tablet_seat(wl_seat) and that returns the actual interface that has all the tablets. With this indirection, we can avoid merging wp_tablet into the actual Wayland protocol, a long-term benefit. The wp_tablet_seat sends a "tablet added" event for each tablet connected. That event is followed by descriptive events about the hardware; currently that includes events for name, vid/pid and a wp_tablet.path event that describes a local path. This path can be used to uniquely identify a tablet or get more information through libwacom. Emulated or nested tablets can skip any of those, e.g. a virtual tablet may not have a vid/pid. The sequence of descriptive events is terminated by a wp_tablet.done event to signal that a client may now finalize any initialization for that tablet. Events from tablets require a tool in proximity. Tools are also managed by the tablet seat; a "tool added" event is sent whenever a tool is new to the compositor. That event is followed by a number of descriptive events about the hardware; currently that includes capabilities, hardware id and serial number, and tool type. Similar to the tablet interface, a wp_tablet_tool.done event is sent to terminate that initial sequence. Any event from a tool happens on the wp_tablet_tool interface. When the tool gets into proximity of the tablet, a proximity_in event is sent on the wp_tablet_tool interface, listing the tablet and the surface. That event is followed by a motion event with the coordinates. After that, it's the usual motion, axis, button, etc. events. The protocol's serialisation means events are grouped by wp_tablet_tool.frame events. Two special events (that don't exist in X) are down and up. They signal "tip touching the surface". For tablets without real proximity detection, the sequence is: proximity_in, motion, down, frame. When the tool leaves proximity, a proximity_out event is sent. If any button is still down, a button release event is sent before this proximity event. These button events are sent in the same frame as the proximity event to signal to the client that the buttons were held when the tool left proximity. If the tool moves out of the surface but stays in proximity (i.e. between windows), compositor-specific grab policies apply. This usually means that the proximity-out is delayed until all buttons are released. Moving a tool physically from one tablet to the other has no real effect on the protocol, since we already have the tool object from the "tool added" event. All the information is already there and the proximity events on both tablets are all a client needs to reconstruct what happened. Some extra axes are normalized, i.e. the client knows the range as specified in the protocol (e.g. [0, 65535]), the granularity however is unknown. The current normalized axes are pressure, distance, and slider. Other extra axes are in physical units as specified in the protocol. The current extra axes with physical units are tilt, rotation and wheel rotation. Since tablets work independently of the pointer controlled by the mouse, the focus handling is independent too and controlled by proximity. The wp_tablet_tool.set_cursor request sets a tool-specific cursor. This cursor surface may be the same as the mouse cursor, and it may be the same across tools but it is possible to be more fine-grained. For example, a client may set different cursors for the pen and eraser. Tools are generally independent of tablets and it is compositor-specific policy when a tool can be removed. Common approaches will likely include some form of removing a tool when all tablets the tool was used on are removed. Warning! The protocol described in this file is experimental and backward incompatible changes may be made. Backward compatible changes may be added together with the corresponding interface version bump. Backward incompatible changes are done by bumping the version number in the protocol and interface names and resetting the interface version. Once the protocol is to be declared stable, the 'z' prefix and the version number in the protocol and interface names are removed and the interface version number is reset. An object that provides access to the graphics tablets available on this system. All tablets are associated with a seat, to get access to the actual tablets, use wp_tablet_manager.get_tablet_seat. Get the wp_tablet_seat object for the given seat. This object provides access to all graphics tablets in this seat. Destroy the wp_tablet_manager object. Objects created from this object are unaffected and should be destroyed separately. An object that provides access to the graphics tablets available on this seat. After binding to this interface, the compositor sends a set of wp_tablet_seat.tablet_added and wp_tablet_seat.tool_added events. Destroy the wp_tablet_seat object. Objects created from this object are unaffected and should be destroyed separately. This event is sent whenever a new tablet becomes available on this seat. This event only provides the object id of the tablet, any static information about the tablet (device name, vid/pid, etc.) is sent through the wp_tablet interface. This event is sent whenever a tool that has not previously been used with a tablet comes into use. This event only provides the object id of the tool; any static information about the tool (capabilities, type, etc.) is sent through the wp_tablet_tool interface. An object that represents a physical tool that has been, or is currently in use with a tablet in this seat. Each wp_tablet_tool object stays valid until the client destroys it; the compositor reuses the wp_tablet_tool object to indicate that the object's respective physical tool has come into proximity of a tablet again. A wp_tablet_tool object's relation to a physical tool depends on the tablet's ability to report serial numbers. If the tablet supports this capability, then the object represents a specific physical tool and can be identified even when used on multiple tablets. A tablet tool has a number of static characteristics, e.g. tool type, hardware_serial and capabilities. These capabilities are sent in an event sequence after the wp_tablet_seat.tool_added event before any actual events from this tool. This initial event sequence is terminated by a wp_tablet_tool.done event. Tablet tool events are grouped by wp_tablet_tool.frame events. Any events received before a wp_tablet_tool.frame event should be considered part of the same hardware state change. Sets the surface of the cursor used for this tool on the given tablet. This request only takes effect if the tool is in proximity of one of the requesting client's 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 cursor 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, in surface-local coordinates. 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. Attach must be confirmed by wl_surface.commit as usual. The hotspot can also be updated by passing the currently set pointer surface to this request with new values for hotspot_x and hotspot_y. The current and pending input regions of the wl_surface are cleared, and wl_surface.set_input_region is ignored until the wl_surface is no longer used as the cursor. When the use as a cursor ends, the current and pending input regions become undefined, and the wl_surface is unmapped. This request gives the surface the role of a cursor. The role assigned by this request is the same as assigned by wl_pointer.set_cursor meaning the same surface can be used both as a wl_pointer cursor and a wp_tablet cursor. If the surface already has another role, it raises a protocol error. The surface may be used on multiple tablets and across multiple seats. This destroys the client's resource for this tool object. Describes the physical type of a tool. The physical type of a tool generally defines its base usage. The mouse tool represents a mouse-shaped tool that is not a relative device but bound to the tablet's surface, providing absolute coordinates. The lens tool is a mouse-shaped tool with an attached lens to provide precision focus. The tool type is the high-level type of the tool and usually decides the interaction expected from this tool. This event is sent in the initial burst of events before the wp_tablet_tool.done event. If the physical tool can be identified by a unique 64-bit serial number, this event notifies the client of this serial number. If multiple tablets are available in the same seat and the tool is uniquely identifiable by the serial number, that tool may move between tablets. Otherwise, if the tool has no serial number and this event is missing, the tool is tied to the tablet it first comes into proximity with. Even if the physical tool is used on multiple tablets, separate wp_tablet_tool objects will be created, one per tablet. This event is sent in the initial burst of events before the wp_tablet_tool.done event. This event notifies the client of a hardware id available on this tool. The hardware id is a device-specific 64-bit id that provides extra information about the tool in use, beyond the wl_tool.type enumeration. The format of the id is specific to tablets made by Wacom Inc. For example, the hardware id of a Wacom Grip Pen (a stylus) is 0x802. This event is sent in the initial burst of events before the wp_tablet_tool.done event. Describes extra capabilities on a tablet. Any tool must provide x and y values, extra axes are device-specific. This event notifies the client of any capabilities of this tool, beyond the main set of x/y axes and tip up/down detection. One event is sent for each extra capability available on this tool. This event is sent in the initial burst of events before the wp_tablet_tool.done event. This event signals the end of the initial burst of descriptive events. A client may consider the static description of the tool to be complete and finalize initialization of the tool. This event is sent when the tool is removed from the system and will send no further events. Should the physical tool come back into proximity later, a new wp_tablet_tool object will be created. It is compositor-dependent when a tool is removed. A compositor may remove a tool on proximity out, tablet removal or any other reason. A compositor may also keep a tool alive until shutdown. If the tool is currently in proximity, a proximity_out event will be sent before the removed event. See wp_tablet_tool.proximity_out for the handling of any buttons logically down. When this event is received, the client must wp_tablet_tool.destroy the object. Notification that this tool is focused on a certain surface. This event can be received when the tool has moved from one surface to another, or when the tool has come back into proximity above the surface. If any button is logically down when the tool comes into proximity, the respective button event is sent after the proximity_in event but within the same frame as the proximity_in event. Notification that this tool has either left proximity, or is no longer focused on a certain surface. When the tablet tool leaves proximity of the tablet, button release events are sent for each button that was held down at the time of leaving proximity. These events are sent before the proximity_out event but within the same wp_tablet.frame. If the tool stays within proximity of the tablet, but the focus changes from one surface to another, a button release event may not be sent until the button is actually released or the tool leaves the proximity of the tablet. Sent whenever the tablet tool comes in contact with the surface of the tablet. If the tool is already in contact with the tablet when entering the input region, the client owning said region will receive a wp_tablet.proximity_in event, followed by a wp_tablet.down event and a wp_tablet.frame event. Note that this event describes logical contact, not physical contact. On some devices, a compositor may not consider a tool in logical contact until a minimum physical pressure threshold is exceeded. Sent whenever the tablet tool stops making contact with the surface of the tablet, or when the tablet tool moves out of the input region and the compositor grab (if any) is dismissed. If the tablet tool moves out of the input region while in contact with the surface of the tablet and the compositor does not have an ongoing grab on the surface, the client owning said region will receive a wp_tablet.up event, followed by a wp_tablet.proximity_out event and a wp_tablet.frame event. If the compositor has an ongoing grab on this device, this event sequence is sent whenever the grab is dismissed in the future. Note that this event describes logical contact, not physical contact. On some devices, a compositor may not consider a tool out of logical contact until physical pressure falls below a specific threshold. Sent whenever a tablet tool moves. Sent whenever the pressure axis on a tool changes. The value of this event is normalized to a value between 0 and 65535. Note that pressure may be nonzero even when a tool is not in logical contact. See the down and up events for more details. Sent whenever the distance axis on a tool changes. The value of this event is normalized to a value between 0 and 65535. Note that distance may be nonzero even when a tool is not in logical contact. See the down and up events for more details. Sent whenever one or both of the tilt axes on a tool change. Each tilt value is in 0.01 of a degree, relative to the z-axis of the tablet. The angle is positive when the top of a tool tilts along the positive x or y axis. Sent whenever the z-rotation axis on the tool changes. The rotation value is in 0.01 of a degree clockwise from the tool's logical neutral position. Sent whenever the slider position on the tool changes. The value is normalized between -65535 and 65535, with 0 as the logical neutral position of the slider. The slider is available on e.g. the Wacom Airbrush tool. Sent whenever the wheel on the tool emits an event. This event contains two values for the same axis change. The degrees value is in 0.01 of a degree in the same orientation as the wl_pointer.vertical_scroll axis. The clicks value is in discrete logical clicks of the mouse wheel. This value may be zero if the movement of the wheel was less than one logical click. Clients should choose either value and avoid mixing degrees and clicks. The compositor may accumulate values smaller than a logical click and emulate click events when a certain threshold is met. Thus, wl_tablet_tool.wheel events with non-zero clicks values may have different degrees values. Describes the physical state of a button that produced the button event. Sent whenever a button on the tool is pressed or released. If a button is held down when the tool moves in or out of proximity, button events are generated by the compositor. See wp_tablet_tool.proximity_in and wp_tablet_tool.proximity_out for details. Marks the end of a series of axis and/or button updates from the tablet. The Wayland protocol requires axis updates to be sent sequentially, however all events within a frame should be considered one hardware event. The wp_tablet interface represents one graphics tablet device. The tablet interface itself does not generate events; all events are generated by wp_tablet_tool objects when in proximity above a tablet. A tablet has a number of static characteristics, e.g. device name and pid/vid. These capabilities are sent in an event sequence after the wp_tablet_seat.tablet_added event. This initial event sequence is terminated by a wp_tablet.done event. This destroys the client's resource for this tablet object. This event is sent in the initial burst of events before the wp_tablet.done event. This event is sent in the initial burst of events before the wp_tablet.done event. A system-specific device path that indicates which device is behind this wp_tablet. This information may be used to gather additional information about the device, e.g. through libwacom. A device may have more than one device path. If so, multiple wp_tablet.path events are sent. A device may be emulated and not have a device path, and in that case this event will not be sent. The format of the path is unspecified, it may be a device node, a sysfs path, or some other identifier. It is up to the client to identify the string provided. This event is sent in the initial burst of events before the wp_tablet.done event. This event is sent immediately to signal the end of the initial burst of descriptive events. A client may consider the static description of the tablet to be complete and finalize initialization of the tablet. Sent when the tablet has been removed from the system. When a tablet is removed, some tools may be removed. When this event is received, the client must wp_tablet.destroy the object.