a11y: managing atk states on EvPageAccessible

This includes:
 * Implements ref_state_set on EvPageAccessible
 * Notify FOCUSED state changes

https://bugzilla.gnome.org/show_bug.cgi?id=724965

origin commit:
https://git.gnome.org/browse/evince/commit/?h=gnome-3-14&id=c421a90

3 files changed, 97 insertions, 0 deletions

diff --git a/libview/ev-page-accessible.c b/libview/ev-page-accessible.c
index 77ae988f..2fcc0680 100644
--- a/libview/ev-page-accessible.c
+++ b/libview/ev-page-accessible.c
@@ -180,6 +180,54 @@ ev_page_accessible_ref_relation_set (AtkObject *accessible)
 	return relation_set;
 }
 
+/* page accessible's state set is a copy ev-view accessible's state
+ * set but removing ATK_STATE_SHOWING if the page is not on screen and
+ * ATK_STATE_FOCUSED if it is not the relevant page. */
+static AtkStateSet *
+ev_page_accessible_ref_state_set (AtkObject *accessible)
+{
+	AtkStateSet *state_set;
+	AtkStateSet *copy_set;
+	AtkStateSet *view_accessible_state_set;
+	EvPageAccessible *self;
+	EvView *view;
+	gint relevant_page;
+
+	g_return_val_if_fail (EV_IS_PAGE_ACCESSIBLE (accessible), NULL);
+	self = EV_PAGE_ACCESSIBLE (accessible);
+	view = ev_page_accessible_get_view (self);
+
+	state_set = ATK_OBJECT_CLASS (ev_page_accessible_parent_class)->ref_state_set (accessible);
+	atk_state_set_clear_states (state_set);
+
+	view_accessible_state_set = atk_object_ref_state_set (ATK_OBJECT (self->priv->view_accessible));
+	copy_set = atk_state_set_or_sets (state_set, view_accessible_state_set);
+
+	if (self->priv->page >= view->start_page && self->priv->page <= view->end_page)
+		atk_state_set_add_state (copy_set, ATK_STATE_SHOWING);
+	else
+		atk_state_set_remove_state (copy_set, ATK_STATE_SHOWING);
+
+	relevant_page = ev_view_accessible_get_relevant_page (self->priv->view_accessible);
+	if (atk_state_set_contains_state (view_accessible_state_set, ATK_STATE_FOCUSED) &&
+	    self->priv->page == relevant_page)
+		atk_state_set_add_state (copy_set, ATK_STATE_FOCUSED);
+	else
+		atk_state_set_remove_state (copy_set, ATK_STATE_FOCUSED);
+
+	relevant_page = ev_view_accessible_get_relevant_page (self->priv->view_accessible);
+	if (atk_state_set_contains_state (view_accessible_state_set, ATK_STATE_FOCUSED) &&
+	    self->priv->page == relevant_page)
+		atk_state_set_add_state (copy_set, ATK_STATE_FOCUSED);
+	else
+		atk_state_set_remove_state (copy_set, ATK_STATE_FOCUSED);
+
+	g_object_unref (state_set);
+	g_object_unref (view_accessible_state_set);
+
+	return copy_set;
+}
+
 static void
 ev_page_accessible_class_init (EvPageAccessibleClass *klass)
 {
@@ -190,6 +238,7 @@ ev_page_accessible_class_init (EvPageAccessibleClass *klass)
 
 	atk_class->get_parent  = ev_page_accessible_get_parent;
 	atk_class->ref_relation_set = ev_page_accessible_ref_relation_set;
+	atk_class->ref_state_set = ev_page_accessible_ref_state_set;
 
 	g_object_class->get_property = ev_page_accessible_get_property;
 	g_object_class->set_property = ev_page_accessible_set_property;
diff --git a/libview/ev-view-accessible.c b/libview/ev-view-accessible.c
index 3f448379..ae55ddd4 100644
--- a/libview/ev-view-accessible.c
+++ b/libview/ev-view-accessible.c
@@ -310,7 +310,16 @@ ev_view_accessible_cursor_moved (EvView *view,
 	EvPageAccessible *page_accessible = NULL;
 
 	if (priv->previous_cursor_page != page) {
+		AtkObject *previous_page = NULL;
+		AtkObject *current_page = NULL;
+
+		previous_page = g_ptr_array_index (priv->children,
+						   priv->previous_cursor_page);
+		atk_object_notify_state_change (previous_page, ATK_STATE_FOCUSED, FALSE);
 		priv->previous_cursor_page = page;
+		current_page = g_ptr_array_index (priv->children, page);
+		atk_object_notify_state_change (current_page, ATK_STATE_FOCUSED, TRUE);
+
 		/* +1 as user start to count on 1, but evince starts on 0 */
 		g_signal_emit_by_name (accessible, "page-changed", page + 1);
 	}
@@ -410,6 +419,27 @@ ev_view_accessible_set_model (EvViewAccessible *accessible,
 	                  accessible);
 }
 
+static gboolean
+ev_view_accessible_focus_changed (GtkWidget        *widget,
+				  GdkEventFocus    *event,
+				  EvViewAccessible *self)
+{
+	AtkObject *page_accessible;
+
+	g_return_val_if_fail (EV_IS_VIEW (widget), FALSE);
+	g_return_val_if_fail (EV_IS_VIEW_ACCESSIBLE (self), FALSE);
+
+	if (self->priv->children == NULL)
+		return FALSE;
+
+	page_accessible = g_ptr_array_index (self->priv->children,
+					     get_relevant_page (EV_VIEW (widget)));
+	atk_object_notify_state_change (page_accessible,
+					ATK_STATE_FOCUSED, event->in);
+
+	return FALSE;
+}
+
 AtkObject *
 ev_view_accessible_new (GtkWidget *widget)
 {
@@ -427,6 +457,12 @@ ev_view_accessible_new (GtkWidget *widget)
 	g_signal_connect (widget, "selection-changed",
 	                  G_CALLBACK (ev_view_accessible_selection_changed),
 	                  accessible);
+	g_signal_connect (widget, "focus-in-event",
+			  G_CALLBACK (ev_view_accessible_focus_changed),
+			  accessible);
+	g_signal_connect (widget, "focus-out-event",
+			  G_CALLBACK (ev_view_accessible_focus_changed),
+			  accessible);
 
 	view = EV_VIEW (widget);
 	if (view->model)
@@ -436,3 +472,14 @@ ev_view_accessible_new (GtkWidget *widget)
 	return accessible;
 }
 
+gint
+ev_view_accessible_get_relevant_page (EvViewAccessible *accessible)
+{
+	EvView *view;
+
+	g_return_val_if_fail (EV_IS_VIEW_ACCESSIBLE (accessible), -1);
+
+	view = EV_VIEW (gtk_accessible_get_widget (GTK_ACCESSIBLE (accessible)));
+
+	return get_relevant_page (view);
+}
diff --git a/libview/ev-view-accessible.h b/libview/ev-view-accessible.h
index 9b62d347..38af95a4 100644
--- a/libview/ev-view-accessible.h
+++ b/libview/ev-view-accessible.h
@@ -53,6 +53,7 @@ AtkObject *ev_view_accessible_new       (GtkWidget *widget);
 void       ev_view_accessible_set_model (EvViewAccessible *accessible,
                                          EvDocumentModel  *model);
 gint       ev_view_accessible_get_n_pages (EvViewAccessible *accessible);
+gint       ev_view_accessible_get_relevant_page (EvViewAccessible *accessible);
 
 #endif  /* __EV_VIEW_ACCESSIBLE_H__ */