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Docs: Add information about event propagation

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Matthias Clasen 2014-05-19 21:24:46 -04:00 committed by Carlos Garnacho
parent aead8a360b
commit ae5f930d1b
1 changed files with 26 additions and 3 deletions
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29
gtk/gtkgesture.c
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@ -44,6 +44,28 @@
* - A number of #GtkGesture::update, whenever an input event is processed. * - A number of #GtkGesture::update, whenever an input event is processed.
* - #GtkGesture::end when the gesture is no longer recognized. * - #GtkGesture::end when the gesture is no longer recognized.
* *
* ## Event propagation
*
* To receive events, a gesture needs to first be attached to its widget with
* gtk_gesture_attach(). The phase passed to this call determines at which
* point in the event processing a gesture operates.
*
* In the capture phase, events are propagated from the toplevel down to the
* target widget, and gestures that are attached to containers above the widget
* get a chance to interact with the event before it reaches the target.
*
* After the capture phase, GTK+ emits the traditional #GtkWidget::button-press,
* #GtkWidget::button-release, #GtkWidget::touch-event, etc signals. Gestures
* with the target phase are fed events from the default #GtkWidget::event
* handlers.
*
* In the bubble phase, events are propagated up from the target widget to the
* toplevel, and gestures that are attached to containers above the widget get
* a chance to interact with events that have not been handled yet.
*
* Gestures attached with the phase 'none' are not receiving any events
* automatically, but events can be passed to them with gtk_gesture_handle_event().
*
* ## States of a sequence # {#touch-sequence-states} * ## States of a sequence # {#touch-sequence-states}
* *
* Whenever input interaction happens, a single event may trigger a cascade of * Whenever input interaction happens, a single event may trigger a cascade of
@ -53,9 +75,10 @@
* in order to enable cooperation of gestures around the #GdkEventSequences * in order to enable cooperation of gestures around the #GdkEventSequences
* triggering those. * triggering those.
* *
* Within a widget, gestures can be grouped through gtk_gesture_group(), grouped * Within a widget, gestures can be grouped through gtk_gesture_group(),
* gestures synchronize the state of sequences, so calling gtk_gesture_set_sequence_state() * grouped gestures synchronize the state of sequences, so calling
* on one will effectively propagate the state throughout the group. * gtk_gesture_set_sequence_state() on one will effectively propagate
* the state throughout the group.
* *
* By default, all sequences start out in the #GTK_EVENT_SEQUENCE_NONE state, * By default, all sequences start out in the #GTK_EVENT_SEQUENCE_NONE state,
* sequences in this state trigger the gesture event handler, but event * sequences in this state trigger the gesture event handler, but event