In particular, this support is targeted at graphics tablets. Graphics tablets typically return sub-pixel positioning information and possibly information about the pressure and tilt of the stylus. Under X, the support for extended devices is done through the XInput extension. Because handling extended input devices may involve considerable overhead, they need to be turned on for each GdkWindow individually using gdk_input_set_extension_events(). (Or, more typically, for GtkWidgets, using gtk_widget_set_extension_events()). As an additional complication, depending on the support from the windowing system, its possible that a normal mouse cursor will not be displayed for a particular extension device. If an application does not want to deal with displaying a cursor itself, it can ask only to get extension events from devices that will display a cursor, by passing the GDK_EXTENSION_EVENTS_CURSOR value to gdk_input_set_extension_events(). Otherwise, the application must retrieve the device information using gdk_devices_list(), check the has_cursor field, and, if it is FALSE, draw a cursor itself when it receives motion events. Each pointing device is assigned a unique integer ID; events from a particular device can be identified by the deviceid field in the event structure. The events generated by pointer devices have also been extended to contain pressure, xtilt and ytilt fields which contain the extended information reported as additional valuators from the device. The pressure field is a a double value ranging from 0.0 to 1.0, while the tilt fields are double values ranging from -1.0 to 1.0. (With -1.0 representing the maximum tilt to the left or up, and 1.0 representing the maximum tilt to the right or down.) One additional field in each event is the source field, which contains an enumeration value describing the type of device; this currently can be one of GDK_SOURCE_MOUSE, GDK_SOURCE_PEN, GDK_SOURCE_ERASER, or GDK_SOURCE_CURSOR. This field is present to allow simple applications to (for instance) delete when they detect eraser devices without having to keep track of complicated per-device settings. Various aspects of each device may be configured. The easiest way of creating a GUI to allow the user to configure such a device is to use the GtkInputDialog widget in GTK+. However, even when using this widget, application writers will need to directly query and set the configuration parameters in order to save the state between invocations of the application. The configuration of devices is queried using gdk_devices_list(). Each device must be activated using gdk_device_set_mode(), which also controls whether the device's range is mapped to the entire screen or to a single window. The mapping of the valuators of the device onto the predefined valuator types is set using gdk_device_set_axis_use(). And the source type for each device can be set with gdk_device_set_source(). Devices may also have associated keys or macro buttons. Such keys can be globally set to map into normal X keyboard events. The mapping is set using gdk_device_set_key(). The interfaces in this section will most likely be considerably modified in the future to accomodate devices that may have different sets of additional valuators than the pressure xtilt and ytilt.
Public Member Functions
|GdkDevice *||getDeviceStruct ()|
|this (GdkDevice *gdkDevice)|
|Sets our main struct and passes it to the parent class. |
|void||setSource (GdkInputSource source)|
|Sets the source type for an input device. |
|int||setMode (GdkInputMode mode)|
|Sets a the mode of an input device. |
|void||setKey (uint index, uint keyval, GdkModifierType modifiers)|
|Specifies the X key event to generate when a macro button of a device is pressed. |
|void||setAxisUse (uint index, GdkAxisUse use)|
|Specifies how an axis of a device is used. |
|void||getState (Window window, double *axes, GdkModifierType *mask)|
|Gets the current state of a device. |
|int||getHistory (Window window, uint start, uint stop, GdkTimeCoord ***events, int *nEvents)|
|Obtains the motion history for a device; given a starting and ending timestamp, return all events in the motion history for the device in the given range of time. |
|int||getAxis (double *axes, GdkAxisUse use, double *value)|
|Interprets an array of double as axis values for a given device, and locates the value in the array for a given axis use. |
Static Public Member Functions
|static ListG||gdkDevicesList ()|
|Returns the list of available input devices for the default display. |
|static Device||getCorePointer ()|
|Returns the core pointer device for the default display. |
|static void||freeHistory (GdkTimeCoord **events, int nEvents)|
|Frees an array of GdkTimeCoord that was returned by gdk_device_get_history(). |
|static void||gdkInputSetExtensionEvents (Window window, int mask, GdkExtensionMode mode)|
|Turns extension events on or off for a particular window, and specifies the event mask for extension events. |
Protected Member Functions
|void *||getStruct ()|
|the main Gtk struct as a void* |
|the main Gtk struct |
Sets our main struct and passes it to the parent class.
Frees an array of GdkTimeCoord that was returned by gdk_device_get_history().
events: an array of GdkTimeCoord. n_events: the length of the array.
|static ListG gdk.Device.Device.gdkDevicesList||(||)||
Returns the list of available input devices for the default display.
The list is statically allocated and should not be freed. Returns: a list of GdkDevice
|static void gdk.Device.Device.gdkInputSetExtensionEvents||(||Window||window,|
Turns extension events on or off for a particular window, and specifies the event mask for extension events.
window: a GdkWindow. mask: the event mask mode: the type of extension events that are desired.
Interprets an array of double as axis values for a given device, and locates the value in the array for a given axis use.
device: a GdkDevice axes: pointer to an array of axes use: the use to look for value: location to store the found value. Returns: TRUE if the given axis use was found, otherwise FALSE
|static Device gdk.Device.Device.getCorePointer||(||)||
Returns the core pointer device for the default display.
Returns: the core pointer device; this is owned by the display and should not be freed.
Obtains the motion history for a device; given a starting and ending timestamp, return all events in the motion history for the device in the given range of time.
Some windowing systems do not support motion history, in which case, FALSE will be returned. (This is not distinguishable from the case where motion history is supported and no events were found.) device: a GdkDevice window: the window with respect to which which the event coordinates will be reported start: starting timestamp for range of events to return stop: ending timestamp for the range of events to return events: location to store a newly-allocated array of GdkTimeCoord, or NULL n_events: location to store the length of events, or NULL Returns: TRUE if the windowing system supports motion history and at least one event was found.
Gets the current state of a device.
device: a GdkDevice. window: a GdkWindow. axes: an array of doubles to store the values of the axes of device in, or NULL. mask: location to store the modifiers, or NULL.
the main Gtk struct as a void*
Specifies how an axis of a device is used.
device: a GdkDevice. index_: the index of the axis. use: specifies how the axis is used.
Specifies the X key event to generate when a macro button of a device is pressed.
device: a GdkDevice. index_: the index of the macro button to set. keyval: the keyval to generate. modifiers: the modifiers to set.
Sets a the mode of an input device.
The mode controls if the device is active and whether the device's range is mapped to the entire screen or to a single window. device: a GdkDevice. mode: the input mode. Returns: TRUE if the mode was successfully changed.
Sets the source type for an input device.
device: a GdkDevice. source: the source type.