Events functions for handling events from the window system. This section describes functions dealing with events from the window system. In GTK+ applications the events are handled automatically in gtk_main_do_event() and passed on to the appropriate widgets, so these functions are rarely needed. Though some of the fields in the Event Structures are useful. Event Structures The structs used for each type of event. Specifies the type of the event. Do not confuse these events with the signals that GTK+ widgets emit. Although many of these events result in corresponding signals being emitted, the events are often transformed or filtered along the way. @GDK_NOTHING: a special code to indicate a null event. @GDK_DELETE: the window manager has requested that the toplevel window be hidden or destroyed, usually when the user clicks on a special icon in the title bar. @GDK_DESTROY: the window has been destroyed. @GDK_EXPOSE: all or part of the window has become visible and needs to be redrawn. @GDK_MOTION_NOTIFY: the pointer (usually a mouse) has moved. @GDK_BUTTON_PRESS: a mouse button has been pressed. @GDK_2BUTTON_PRESS: a mouse button has been double-clicked (clicked twice within a short period of time). Note that each click also generates a %GDK_BUTTON_PRESS event. @GDK_3BUTTON_PRESS: a mouse button has been clicked 3 times in a short period of time. Note that each click also generates a %GDK_BUTTON_PRESS event. @GDK_BUTTON_RELEASE: a mouse button has been released. @GDK_KEY_PRESS: a key has been pressed. @GDK_KEY_RELEASE: a key has been released. @GDK_ENTER_NOTIFY: the pointer has entered the window. @GDK_LEAVE_NOTIFY: the pointer has left the window. @GDK_FOCUS_CHANGE: the keyboard focus has entered or left the window. @GDK_CONFIGURE: the size, position or stacking order of the window has changed. Note that GTK+ discards these events for %GDK_WINDOW_CHILD windows. @GDK_MAP: the window has been mapped. @GDK_UNMAP: the window has been unmapped. @GDK_PROPERTY_NOTIFY: a property on the window has been changed or deleted. @GDK_SELECTION_CLEAR: the application has lost ownership of a selection. @GDK_SELECTION_REQUEST: another application has requested a selection. @GDK_SELECTION_NOTIFY: a selection has been received. @GDK_PROXIMITY_IN: an input device has moved into contact with a sensing surface (e.g. a touchscreen or graphics tablet). @GDK_PROXIMITY_OUT: an input device has moved out of contact with a sensing surface. @GDK_DRAG_ENTER: the mouse has entered the window while a drag is in progress. @GDK_DRAG_LEAVE: the mouse has left the window while a drag is in progress. @GDK_DRAG_MOTION: the mouse has moved in the window while a drag is in progress. @GDK_DRAG_STATUS: the status of the drag operation initiated by the window has changed. @GDK_DROP_START: a drop operation onto the window has started. @GDK_DROP_FINISHED: the drop operation initiated by the window has completed. @GDK_CLIENT_EVENT: a message has been received from another application. @GDK_VISIBILITY_NOTIFY: the window visibility status has changed. @GDK_NO_EXPOSE: indicates that the source region was completely available when parts of a drawable were copied. This is not very useful. @GDK_SCROLL: A set of bit-flags to indicate which events a window is to receive. Most of these masks map onto one or more of the #GdkEventType event types above. %GDK_POINTER_MOTION_HINT_MASK is a special mask which is used to reduce the number of %GDK_MOTION_NOTIFY events received. Normally a %GDK_MOTION_NOTIFY event is received each time the mouse moves. However, if the application spends a lot of time processing the event (updating the display, for example), it can easily lag behind the position of the mouse. When using the %GDK_POINTER_MOTION_HINT_MASK the server will only send %GDK_MOTION_NOTIFY events when the application asks for them, by calling gdk_window_get_pointer(). @GDK_EXPOSURE_MASK: @GDK_POINTER_MOTION_MASK: @GDK_POINTER_MOTION_HINT_MASK: @GDK_BUTTON_MOTION_MASK: @GDK_BUTTON1_MOTION_MASK: @GDK_BUTTON2_MOTION_MASK: @GDK_BUTTON3_MOTION_MASK: @GDK_BUTTON_PRESS_MASK: @GDK_BUTTON_RELEASE_MASK: @GDK_KEY_PRESS_MASK: @GDK_KEY_RELEASE_MASK: @GDK_ENTER_NOTIFY_MASK: @GDK_LEAVE_NOTIFY_MASK: @GDK_FOCUS_CHANGE_MASK: @GDK_STRUCTURE_MASK: @GDK_PROPERTY_CHANGE_MASK: @GDK_VISIBILITY_NOTIFY_MASK: @GDK_PROXIMITY_IN_MASK: @GDK_PROXIMITY_OUT_MASK: @GDK_SUBSTRUCTURE_MASK: @GDK_SCROLL_MASK: @GDK_ALL_EVENTS_MASK: the combination of all the above event masks. Represents the current time, and can be used anywhere a time is expected. This is the priority that events from the X server are given in the GLib Main Loop. Checks if any events are waiting to be processed. @Returns: TRUE if any events are pending. Gets a copy of the first #GdkEvent in the event queue. (Note that this function will not get more events from the X server. It only checks the events that have already been moved to the GDK event queue.) @Returns: a copy of the first #GdkEvent on the event queue, or NULL if no events are in the queue. The returned #GdkEvent should be freed with gdk_event_free(). Gets the next #GdkEvent to be processed, fetching events from the X server if necessary. @Returns: the next #GdkEvent to be processed, or NULL if no events are pending. The returned #GdkEvent should be freed with gdk_event_free(). Waits for a GraphicsExpose or NoExpose event from the X server. This is used in the #GtkText and #GtkCList widgets in GTK+ to make sure any GraphicsExpose events are handled before the widget is scrolled. @window: the #GdkWindow to wait for the events for. @Returns: a #GdkEventExpose if a GraphicsExpose was received, or NULL if a NoExpose event was received. Appends a copy of the given event onto the front of the event queue. @event: a #GdkEvent. Copies a #GdkEvent, copying or incrementing the reference count of the resources associated with it (e.g. #GdkWindow's and strings). @event: a #GdkEvent. @Returns: a copy of @event. The returned #GdkEvent should be freed with gdk_event_free(). Frees a #GdkEvent, freeing or decrementing any resources associated with it. Note that this function should only be called with events returned from gdk_event_peek(), gdk_event_get(), gdk_event_get_graphics_expose() and gdk_event_copy(). @event: a #GdkEvent. Gets the timestamp from a #GdkEvent. @event: a #GdkEvent. @Returns: the timestamp from @event, or #GDK_CURRENT_TIME if the event has no timestamp. @event: @axis_use: @value: @Returns: Sets the function to call to handle all events from GDK. Note that GTK+ uses this to install its own event handler, so it is probably not useful for GTK+ applications. @func: the function to call to handle events from GDK. @data: user data to pass to the function. @notify: the function to call when the handler function is removed, i.e. when gdk_event_handler_set() is called with another event handler. Specifies the type of function passed to gdk_event_handler_set() to handle all GDK events. @event: the #GdkEvent to process. @data: user data set when the event handler was installed with gdk_event_handler_set(). Sends an X ClientMessage event to a given window. This could be used for communicating between different applications, though the amount of data is limited to 20 bytes. @event: the #GdkEvent to send, which should be a #GdkEventClient. @xid: the window to send the X ClientMessage event to. @Returns: non-zero on success. Sends an X ClientMessage event to all toplevel windows. Toplevel windows are determined by checking for the WM_STATE property, as described in the Inter-Client Communication Conventions Manual (ICCCM). If no windows are found with the WM_STATE property set, the message is sent to all children of the root window. @event: the #GdkEvent to send, which should be a #GdkEventClient. Adds a filter to be called when X ClientMessage events are received. @message_type: the type of ClientMessage events to receive. This will be checked against the message_type field of the XClientMessage event struct. @func: the function to call to process the event. @data: user data to pass to @func. Returns non-zero if event debugging output is enabled. @Returns: non-zero if event debugging output is enabled. Sets whether event debugging information is output. Note that GTK+ must be compiled with debugging enabled, i.e. using the '--enable-debug' configure option. @show_events: TRUE to output event debugging information.