Event Structures Data structures specific to each type of event The event structs contain data specific to each type of event in GDK. A common mistake is to forget to set the event mask of a widget so that the required events are received. See gtk_widget_set_events(). The #GdkEvent struct contains a union of all of the event structs, and allows access to the data fields in a number of ways. The event type is always the first field in all of the event structs, and can always be accessed with the following code, no matter what type of event it is: GdkEvent *event; GdkEventType type; type = event->type; To access other fields of the event structs, the pointer to the event can be cast to the appropriate event struct pointer, or the union member name can be used. For example if the event type is %GDK_BUTTON_PRESS then the x coordinate of the button press can be accessed with: GdkEvent *event; gdouble x; x = ((GdkEventButton*)event)->x; or: GdkEvent *event; gdouble x; x = event->button.x; Contains the fields which are common to all event structs. Any event pointer can safely be cast to a pointer to a #GdkEventAny to access these fields. @type: the type of the event. @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). Describes a key press or key release event. @type: the type of the event (%GDK_KEY_PRESS or %GDK_KEY_RELEASE). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @time: the time of the event in milliseconds. @state: a bit-mask representing the state of the modifier keys (e.g. Control, Shift and Alt) and the pointer buttons. See #GdkModifierType. @keyval: the key that was pressed or released. See the <gdk/gdkkeysyms.h> header file for a complete list of GDK key codes. @length: the length of @string. @string: a string containing the an approximation of the text that would result from this keypress. The only correct way to handle text input of text is using input methods (see #GtkIMContext), so this field is deprecated and should never be used. (gdk_unicode_to_keyval() provides a non-deprecated way of getting an approximate translation for a key.) The string is encoded in the encoding of the current locale (Note: this for backwards compatibility: strings in GTK+ and GDK are typically in UTF-8.) and NUL-terminated. In some cases, the translation of the key code will be a single NUL byte, in which case looking at @length is necessary to distinguish it from the an empty translation. @hardware_keycode: the raw code of the key that was pressed or released. @group: the keyboard group. Used for button press and button release events. The type field will be one of %GDK_BUTTON_PRESS, %GDK_2BUTTON_PRESS, %GDK_3BUTTON_PRESS, and %GDK_BUTTON_RELEASE. Double and triple-clicks result in a sequence of events being received. For double-clicks the order of events will be: %GDK_BUTTON_PRESS %GDK_BUTTON_RELEASE %GDK_BUTTON_PRESS %GDK_2BUTTON_PRESS %GDK_BUTTON_RELEASE Note that the first click is received just like a normal button press, while the second click results in a %GDK_2BUTTON_PRESS being received just after the %GDK_BUTTON_PRESS. Triple-clicks are very similar to double-clicks, except that %GDK_3BUTTON_PRESS is inserted after the third click. The order of the events is: %GDK_BUTTON_PRESS %GDK_BUTTON_RELEASE %GDK_BUTTON_PRESS %GDK_2BUTTON_PRESS %GDK_BUTTON_RELEASE %GDK_BUTTON_PRESS %GDK_3BUTTON_PRESS %GDK_BUTTON_RELEASE For a double click to occur, the second button press must occur within 1/4 of a second of the first. For a triple click to occur, the third button press must also occur within 1/2 second of the first button press. @type: the type of the event (%GDK_BUTTON_PRESS, %GDK_2BUTTON_PRESS, %GDK_3BUTTON_PRESS or %GDK_BUTTON_RELEASE). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @time: the time of the event in milliseconds. @x: the x coordinate of the pointer relative to the window. @y: the y coordinate of the pointer relative to the window. @axes: @x, @y translated to the axes of @device, or %NULL if @device is the mouse. @state: a bit-mask representing the state of the modifier keys (e.g. Control, Shift and Alt) and the pointer buttons. See #GdkModifierType. @button: the button which was pressed or released, numbered from 1 to 5. Normally button 1 is the left mouse button, 2 is the middle button, and 3 is the right button. On 2-button mice, the middle button can often be simulated by pressing both mouse buttons together. @device: the device where the event originated. @x_root: the x coordinate of the pointer relative to the root of the screen. @y_root: the y coordinate of the pointer relative to the root of the screen. Generated from button presses for the buttons 4 to 7. Wheel mice are usually configured to generate button press events for buttons 4 and 5 when the wheel is turned. @type: the type of the event (%GDK_SCROLL). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @time: the time of the event in milliseconds. @x: the x coordinate of the pointer relative to the window. @y: the y coordinate of the pointer relative to the window. @state: a bit-mask representing the state of the modifier keys (e.g. Control, Shift and Alt) and the pointer buttons. See #GdkModifierType. @direction: the direction to scroll to (one of %GDK_SCROLL_UP, %GDK_SCROLL_DOWN, %GDK_SCROLL_LEFT and %GDK_SCROLL_RIGHT). @device: the device where the event originated. @x_root: the x coordinate of the pointer relative to the root of the screen. @y_root: the y coordinate of the pointer relative to the root of the screen. Generated when the pointer moves. @type: the type of the event. @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @time: the time of the event in milliseconds. @x: the x coordinate of the pointer relative to the window. @y: the y coordinate of the pointer relative to the window. @axes: @x, @y translated to the axes of @device, or %NULL if @device is the mouse. @state: a bit-mask representing the state of the modifier keys (e.g. Control, Shift and Alt) and the pointer buttons. See #GdkModifierType. @is_hint: set to 1 if this event is just a hint, see the %GDK_POINTER_MOTION_HINT_MASK value of #GdkEventMask. @device: the device where the event originated. @x_root: the x coordinate of the pointer relative to the root of the screen. @y_root: the y coordinate of the pointer relative to the root of the screen. Generated when all or part of a window becomes visible and needs to be redrawn. @type: the type of the event (%GDK_EXPOSE). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @area: bounding box of @region. @region: the region that needs to be redrawn. @count: the number of contiguous %GDK_EXPOSE events following this one. The only use for this is "exposure compression", i.e. handling all contiguous %GDK_EXPOSE events in one go, though GDK performs some exposure compression so this is not normally needed. Generated when the window visibility status has changed. @type: the type of the event (%GDK_VISIBILITY_NOTIFY). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @state: the new visibility state (%GDK_VISIBILITY_FULLY_OBSCURED, %GDK_VISIBILITY_PARTIAL or %GDK_VISIBILITY_UNOBSCURED). Generated when the pointer enters or leaves a window. @type: the type of the event (%GDK_ENTER_NOTIFY or %GDK_LEAVE_NOTIFY). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @subwindow: the window that was entered or left. @time: the time of the event in milliseconds. @x: the x coordinate of the pointer relative to the window. @y: the y coordinate of the pointer relative to the window. @x_root: the x coordinate of the pointer relative to the root of the screen. @y_root: the y coordinate of the pointer relative to the root of the screen. @mode: the crossing mode (%GDK_CROSSING_NORMAL, %GDK_CROSSING_GRAB or %GDK_CROSSING_UNGRAB). @detail: the kind of crossing that happened (%GDK_NOTIFY_INFERIOR, %GDK_NOTIFY_ANCESTOR, %GDK_NOTIFY_VIRTUAL, %GDK_NOTIFY_NONLINEAR or %GDK_NOTIFY_NONLINEAR_VIRTUAL). @focus: %TRUE if @window is the focus window or an inferior. @state: a bit-mask representing the state of the modifier keys (e.g. Control, Shift and Alt) and the pointer buttons. See #GdkModifierType. Describes a change of keyboard focus. @type: the type of the event (%GDK_FOCUS_CHANGE). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @in: %TRUE if the window has gained the keyboard focus, %FALSE if it has lost the focus. Generated when a window size or position has changed. @type: the type of the event (%GDK_CONFIGURE). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @x: the new x coordinate of the window, relative to its parent. @y: the new y coordinate of the window, relative to its parent. @width: the new width of the window. @height: the new height of the window. Describes a property change on a window. @type: the type of the event (%GDK_PROPERTY_NOTIFY). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @atom: the property that was changed. @time: the time of the event in milliseconds. @state: whether the property was changed (%GDK_PROPERTY_NEW_VALUE) or deleted (%GDK_PROPERTY_DELETE). Generated when a selection is requested or ownership of a selection is taken over by another client application. @type: the type of the event (%GDK_SELECTION_CLEAR, %GDK_SELECTION_NOTIFY or %GDK_SELECTION_REQUEST). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @selection: the selection. @target: the target to which the selection should be converted. @property: the property in which to place the result of the conversion. @time: the time of the event in milliseconds. @requestor: the native window on which to place @property. Used to represent native windows (Windows for the X11 backend, HWNDs for Win32). Generated during DND operations. @type: the type of the event (%GDK_DRAG_ENTER, %GDK_DRAG_LEAVE, %GDK_DRAG_MOTION, %GDK_DRAG_STATUS, %GDK_DROP_START or %GDK_DROP_FINISHED). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @context: the #GdkDragContext for the current DND operation. @time: the time of the event in milliseconds. @x_root: the x coordinate of the pointer relative to the root of the screen, only set for %GDK_DRAG_MOTION and %GDK_DROP_START. @y_root: the y coordinate of the pointer relative to the root of the screen, only set for %GDK_DRAG_MOTION and %GDK_DROP_START. Proximity events are generated when using GDK's wrapper for the XInput extension. The XInput extension is an add-on for standard X that allows you to use nonstandard devices such as graphics tablets. A proximity event indicates that the stylus has moved in or out of contact with the tablet, or perhaps that the user's finger has moved in or out of contact with a touch screen. @type: the type of the event (%GDK_PROXIMITY_IN or %GDK_PROXIMITY_OUT). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @time: the time of the event in milliseconds. @device: the device where the event originated. An event sent by another client application. @type: the type of the event (%GDK_CLIENT_EVENT). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @message_type: the type of the message, which can be defined by the application. @data_format: the format of the data, given as the number of bits in each data element, i.e. 8, 16, or 32. 8-bit data uses the b array of the data union, 16-bit data uses the s array, and 32-bit data uses the l array. Generated when the area of a #GdkDrawable being copied, with gdk_draw_drawable() or gdk_window_copy_area(), was completely available. FIXME: add more here. @type: the type of the event (%GDK_NO_EXPOSE). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). Generated when the state of a toplevel window changes. @type: the type of the event (%GDK_WINDOW_STATE). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @changed_mask: mask specifying what flags have changed. @new_window_state: the new window state, a combination of #GdkWindowState bits. Generated when a setting is modified. @type: the type of the event (%GDK_SETTING). @window: the window which received the event. @send_event: %TRUE if the event was sent explicitly (e.g. using XSendEvent). @action: what happened to the setting (%GDK_SETTING_ACTION_NEW, %GDK_SETTING_ACTION_CHANGED or %GDK_SETTING_ACTION_DELETED). @name: the name of the setting. @type: @window: @send_event: @owner: @reason: @selection: @time: @selection_time: Specifies the direction for #GdkEventScroll. @GDK_SCROLL_UP: the window is scrolled up. @GDK_SCROLL_DOWN: the window is scrolled down. @GDK_SCROLL_LEFT: the window is scrolled to the left. @GDK_SCROLL_RIGHT: the window is scrolled to the right. Specifies the visiblity status of a window for a #GdkEventVisibility. @GDK_VISIBILITY_UNOBSCURED: the window is completely visible. @GDK_VISIBILITY_PARTIAL: the window is partially visible. @GDK_VISIBILITY_FULLY_OBSCURED: the window is not visible at all. Specifies the crossing mode for #GdkEventCrossing. @GDK_CROSSING_NORMAL: crossing because of pointer motion. @GDK_CROSSING_GRAB: crossing because a grab is activated. @GDK_CROSSING_UNGRAB: crossing because a grab is deactivated. Specifies the kind of crossing for #GdkEventCrossing. See the X11 protocol specification of LeaveNotify for full details of crossing event generation. @GDK_NOTIFY_ANCESTOR: the window is entered from an ancestor or left towards an ancestor. @GDK_NOTIFY_VIRTUAL: the pointer moves between an ancestor and an inferior of the window. @GDK_NOTIFY_INFERIOR: the window is entered from an inferior or left towards an inferior. @GDK_NOTIFY_NONLINEAR: the window is entered from or left towards a window which is neither an ancestor nor an inferior. @GDK_NOTIFY_NONLINEAR_VIRTUAL: the pointer moves between two windows which are not ancestors of each other and the window is part of the ancestor chain between one of these windows and their least common ancestor. @GDK_NOTIFY_UNKNOWN: Specifies the type of a property change for a #GdkEventProperty. @GDK_PROPERTY_NEW_VALUE: the property value was changed. @GDK_PROPERTY_DELETE: the property was deleted. Specifies the state of a toplevel window. @GDK_WINDOW_STATE_WITHDRAWN: the window is not shown. @GDK_WINDOW_STATE_ICONIFIED: the window is minimized. @GDK_WINDOW_STATE_MAXIMIZED: the window is maximized. @GDK_WINDOW_STATE_STICKY: the window is sticky. @GDK_WINDOW_STATE_FULLSCREEN: the window is maximized without decorations. @GDK_WINDOW_STATE_ABOVE: the window is kept above other windows. @GDK_WINDOW_STATE_BELOW: the window is kept below other windows. Specifies the kind of modification applied to a setting in a #GdkEventSetting. @GDK_SETTING_ACTION_NEW: a setting was added. @GDK_SETTING_ACTION_CHANGED: a setting was changed. @GDK_SETTING_ACTION_DELETED: a setting was deleted. @GDK_OWNER_CHANGE_NEW_OWNER: @GDK_OWNER_CHANGE_DESTROY: @GDK_OWNER_CHANGE_CLOSE: