TUHI ===== Tuhi is a DBus session daemon that connects to and fetches the data from the Wacom ink range (Spark, Slate, Folio, Intuos Paper, ...). The data is provided to clients in the form of JSON, any conversion to other formats like SVG must be done by the clients. Tuhi is the Maori word for "to draw". Supported Devices ----------------- Devices tested and known to be supported: * Bamboo Spark * Bamboo Slate Warning ------- A device can only be paired with one application at a time. Thus, when a device is paired with Tuhi, other applications (e.g. Wacom Inkspace) cannot not connect to the device anymore. Likewise, when paired with another application, Tuhi cannot connect. To make the tablet connect again, simply re-pair with the respective application or Tuhi, whichever desired. The reason for this behavior is that pairing assigns a application-generated unique UUID to the device. Subsequent connections must use that UUID for the tablet device to respond. Without knowing that UUID, other applications cannot connect. Installation ------------ ``` $> git clone http://github.com/tuhiproject/tuhi $> cd tuhi $> python3 setup.py install $> tuhi ``` TUHI requires Python v3.6 or above. Units used by this interface ---------------------------- * Physical distances for x/y axes are in µm from the sensor's top-left position. (Note that on the Spark and on the Slate at least, the sensor is turned 90 degrees clockwise, so (0,0) is at the 'natural' top-right corner) * Stylus pressure is normalized to a range of [0, 0xffff], inclusive. * Timestamps are in seconds in unix epoch, time offsets are in ms after the most recent timestamp. DBus Interface -------------- The following interfaces are provided: ``` org.freedesktop.tuhi1.Manager Property: Devices (ao) Array of object paths to known (previously paired, but not necessarily connected) devices. Note that a "paired" device is one that has been initialized via the Wacom SmartPad custom protocol. This initialization is independent of the Bluetooth pairing process. A Tuhi paired device may or may not be paired over Bluetooth. Property: Searching (b) Indicates whether the daemon is currently searching for pairable devices. This property is set to True when a StartSearching() request initiates the search for device connections. When the StartSearching() request completes upon timeout, or when StopSearching() is called, the property is set to False. When a pariable device is found, the PairableDevice signal is sent to the caller that initiated the search process. Read-only Method: StartSearch() -> () Start searching for available devices in pairing mode for an unspecified timeout. When the timeout expires or an error occurs, a SearchStopped signal is sent indicating success or error. If a client that successfully initated a listening process calls StartSearching() again, that call is ignored and no signal is generated for that call. Method: StopSearch() -> () Stop listening to available devices in pairing mode. If called after StartSearch() and before a SearchStopped signal has been received, this method triggers the SearchStopped signal. That signal indicates success or an error. If this method is called before StartSearch() or after the SearchStopped signal, it is ignored and no signal is generated. Note that between calling StopSearch() and the SearchStopped signal arriving, PairableDevice signals may still arrive. Signal: PairableDevice(o) Indicates that a device is available for pairing. This signal may be sent after a StartSearch() call and before SearchStopped(). This signal is sent once per available device and only to the client that initiated the search process with StartSearch. When this signal is sent, a org.freedesktop.tuhi1.Device object was created, the object path is the argument to this signal. A client must immediately call Pair() on that object if pairing with that object is desired. See the documentation for that interface for details. When the search timeout expires, the device may be removed by the daemon again. Note that until the device is paired, the device is not listed in the managers Devices property. Signal: SearchStopped(i) Sent when the search has stopped. An argument of 0 indicates a successful termination of the search process, either when a device has been paired or the timeout expired. If the errno is -EAGAIN, the daemon is already searching for devices on behalf of another client. In this case, this client should wait for the Searching property to change and StartSearching() once the property is set to False. Once this signal has been sent, all devices announced through PairableDevice signals should be considered invalidated. Attempting to Pair() one of the devices after the SearchStopped() signal may result in an error. In case of error, the argument is a negative errno. org.freedesktop.tuhi1.Device Interface to a device known by tuhi. Each object in Manager.Devices implements this interface. Property: Name (s) Human-readable name of the device. Read-only Property: Address (s) Bluetooth address of the device. Read-only Property: Dimensions (uu) The physical dimensions (width, height) in µm Read-only Property: BatteryPercent (u) The last known battery charge level in percent. This charge level is only accurate when the BatteryState is other than Unknown. When the BatteryState is Unknown and BatteryPercent is nonzero, the value is the last known percentage value. Read-only Property: BatteryState (u) An enum describing the battery state. Permitted enum values are 0: Unknown 1: Charging 2: Discharging 'Unknown' may refer to a state that could not be read, a state that has not yet been updated, or a state that has not updated within a daemon-internal time period. Thus, a device that is connected but does not regularly send battery updates may eventually switch to 'Unknown'. Read-only Property: DrawingsAvailable (at) An array of timestamps of the available drawings. The timestamp of each drawing can be used as argument to GetJSONData(). Timestamps are in seconds since the Epoch and may be used to display information to the user or sort data. Read-only Property: Listening (b) Indicates whether the daemon is currently listening for the device. This property is set to True when a StartListening() request initiates the search for device connections. When the StartListening() request completes upon timeout, or when StopListening() is called, the property is set to False. When the user press the button on the device, the daemon connects to the device, downloads all drawings from the device and disconnects from the device. If successfull, the drawings are deleted from the device. The data is held by the daemon in non-persistent storage until the daemon is stopped or we run out of memory, whichever happens earlier. Use GetJSONData() to retrieve the data from the daemon. DO NOT RELY ON THE DAEMON FOR PERMANENT STORAGE When drawings become available from the device, the DrawingsAvailable property updates to the number of available drawings. When the button is pressed multiple times, any new data is appended to the existing list of drawings as long as this property is True. Read-only Method: Pair() -> (i) Pair the device. If the device is already paired, calls to this method immediately return success. Otherwise, the device is paired and this function returns success (0) or a negative errno on failure. Method: StartListening() -> () Listen for data from this device and connect to the device when it becomes available. The daemon listens to the device until the client calls StopListening() or the client disconnects, whichever happens earlier. The ListeningStopped signal is sent when the listening terminates, either on success or with an error. A client should handle this signal to be notified of any errors. When the daemon starts listening, the Listening property is updated accordingly. If a client that successfully initated a listening process calls StartListening() again, that call is ignored and no signal is generated for that call. Method: StopListening() -> () Stop listening for data on this device. If called after StartListening(), this method triggers the ListenStopped signal. That signal indicates success or an error. If this method is called before StartListening() or after the ListeningStopped signal, it is ignored and no signal is generated. Note that between calling StopListening() and the ListeningStopped signal arriving, the property DrawingsAvailable may still be updated and it's the responsibility of the client to fetch the JSON data. Method: GetJSONData(timestamp: t) -> (s) Returns a JSON file with the drawings specified by the timestamp argument. Drawings are zero-indexed and the requested index must be less than the DrawingsAvailable property value. See section JSON FILE FORMAT for the format of the returned data. Returns a string representing the JSON data from the last drawings or the empty string if no data is available or the timestamp is invalid. Signal: ButtonPressRequired() Sent when the user is expected to press the physical button on the device. A client should display a notification in response, if the user does not press the button during the (firmware-specific) timeout the current operation will fail. Signal: ListeningStopped(i) Sent when the listen process has stopped. An argument of 0 indicates a successful termination, i.e. in response to the client calling StopListening(). Otherwise, the argument is a negative errno indicating the type of error. If the errno is -EAGAIN, the daemon is already listening to the device on behalf of another client. In this case, this client should wait for the Listening property to change and StartListening() once the property is set to False. If the error is -EBADE, the device is not in pairing/listening mode and pairing/listening was requested. In this case, the client should indicate to the user that the device needs to be paired first or switched to listening mode. If the error is -EACCES, the device is not paired with the daemon or incorrectly paired. This may happen when the device was paired with another host since the last connection. The following other errnos may be sent by the daemon: -EPROTO: the daemon has encountered a protocol error with the device. -ETIME: timeout while communicating with the device. These errnos indicate a bug in the daemon, and the client should display a message to that effect. ``` JSON File Format ---------------- Below is the example file format (with comments, not present in the real files). The JSON objects are "drawing" (the root object), "strokes", "points". Pseudo-code is used to illustrate the objects in the file. ``` class Drawing { version: uint32 devicename: string dimensions: [uint32, uint32] // x/y physical dimensions in µm timestamp: uint64 strokes: [ Stroke, Stroke, ...] } ``` The **strokes** list contains all strokes of a single drawing, each stroke consisting of a number of **points**. ``` class Stroke { points: [Point, Point, ...] } ``` The **points** list contains the actual pen data. ``` class Point { toffset: uint32 position: [uint32, uint32] pressure: uint32 } ``` An expanded file looks like this: ``` { "version" : 1, // JSON file format version number "devicename": "Wacom Bamboo Spark", "dimensions": [ 100000, 200000], // width/height in µm "timestamp" : 12345, "strokes" : [ { "points": [ // all items in a point are optional. Unknown dictionary // entries must be ignored as future devices may add // new axes. { "toffset" : 12366, "position" : [ 100, 200 ], "pressure" : 1000 }, { "toffset" : 12368, "pressure" : 800 }, { "toffset" : 12366, "position" : [ 120, 202 ] }, ] }, { "points" : ... } ] } ``` Device notes ============ When following any device notes below, replace the example bluetooth addresses with your device's bluetooth address. Bamboo Spark ------------ The Bluetooth connection on the Bamboo Spark behaves differently depending on whether there are drawings pending or not. Generally, if no drawings are pending, it is harder to connect to the device. Save yourself the pain and make sure you have drawings pending while debugging. ### If the device has no drawings available: * start `bluetoothctl`, commands below are to be issued in its interactive shell * enable discovery mode (`scan on`) * hold the Bamboo Spark button until the blue light is flashing * You should see the device itself show up, but none of its services ``` [NEW] Device E2:43:03:67:0E:01 Bamboo Spark ``` * While the LED is still flashing, `connect E2:43:03:67:0E:01` ``` Attempting to connect to E2:43:03:67:0E:01 [CHG] Device E2:43:03:67:0E:01 Connected: yes ... lots of services being resolved [CHG] Device E2:43:03:67:0E:01 ServicesResolved: yes [CHG] Device E2:43:03:67:0E:01 ServicesResolved: no [CHG] Device E2:43:03:67:0E:01 Connected: no ``` Note how the device disconnects again at the end. Doesn't matter, now you have the services cached. * Don't forget to eventually turn disable discovery mode off (`scan off`) Now you have the device cached in bluez and you can work with that data. However, you **cannot connect to the device while it has no drawings pending**. Running `connect` and pressing the Bamboo Spark button shortly does nothing. ### If the device has drawings available: * start `bluetoothctl`, commands below are to be issued in its interactive shell * enable discovery mode (`scan on`) * press the Bamboo Spark button shortly * You should see the device itself show up, but none of its services ``` [NEW] Device E2:43:03:67:0E:01 Bamboo Spark ``` * `connect E2:43:03:67:0E:01`, then press the Bamboo Spark button ``` Attempting to connect to E2:43:03:67:0E:01 [CHG] Device E2:43:03:67:0E:01 Connected: yes ... lots of services being resolved [CHG] Device E2:43:03:67:0E:01 ServicesResolved: yes [CHG] Device E2:43:03:67:0E:01 ServicesResolved: no [CHG] Device E2:43:03:67:0E:01 Connected: no ``` Note how the device disconnects again at the end. Doesn't matter, now you have the services cached. * `connect E2:43:03:67:0E:01`, then press the Bamboo Spark button re-connects to the device The device will disconnect after approximately 10s. You need to start issuing the commands to talk to the controller before that happens. * Don't forget to eventually turn disable discovery mode off (`scan off`) You **must** run `connect` before pressing the button. Just pressing the button does nothing unless bluez is trying to connect to the device. **Warning**: A successful communication with the controller deletes the drawings from the controller, so you may not be able to re-connect.