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 Units used by this interface ---------------------------- * Physical distances for x/y axes are in µm from the sensor's top-right position. * 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. 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: DrawingsAvailable (u) An integer indicating the number of drawings available. Drawings are zero-indexed, see GetJSONData(). Read-only Property: Listening (b) Indicates whether the daemon is currently listening for the device. This property is set to True when a Listen() request initiates the search for device connections. When the Listen() request completes upon timeout, the property is set to False. Read-only Method: Listen() -> () Listen for data from this device. This method starts listening for events on the device for an unspecified timeout. When the timeout expires, a ListenComplete signal is sent indicating success or error. This function requires the device to be connected and may require some interactivity (e.g. the user may need to press the sync button). When the device connects, the daemon downloads all drawings 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. When drawings become available from the device, the DrawingsAvailable property updates to the number of available drawings. When this function is called multiple times, any new data is appended to the existing list of drawings. Calling Listen() before a previous call has completed is silently ignored and does not reset the timeout. Returns: 0 on success or a negative errno on failure Method: GetJSONData(index: u) -> (s) Returns a JSON file with the drawings specified by the index 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 index is invalid. ``` 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.