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StWidgetAccessible: accessibility support for StWidget

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It includes:

 * Expose a proper focusable state, instead of the default one from
   cally, using StWidget::can_focus, and also notifying the state change

 * Management of the selected stated, using the current pseudo_class.

 * Defines a new virtual method on StWidget: get_accessible_type. In
   this way it is not required to reimplement get_accessible just for
   a accessible type change. get_accessible is reimplemented using this.
   You can see that as a substitute of the atk object factory

https://bugzilla.gnome.org/show_bug.cgi?id=636716
This commit is contained in:
Alejandro Piñeiro 2011-01-04 13:14:15 +01:00
parent 13cc58937e
commit 125adb4d32
4 changed files with 284 additions and 0 deletions
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1
src/Makefile-st.am
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@ -98,6 +98,7 @@ st_source_h = \
st/st-tooltip.h \
st/st-types.h \
st/st-widget.h \
st/st-widget-accessible.h \
$(NULL)
st.h: stamp-st.h

76
src/st/st-widget-accessible.h Normal file
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@ -0,0 +1,76 @@
/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*- */
/*
* st-widget-accessible.h: Accessible object for StWidget
*
* Copyright 2010 Igalia, S.L.
* Author: Alejandro Piñeiro Iglesias <apinheiro@igalia.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU Lesser General Public License,
* version 2.1, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
* more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#if !defined(ST_H_INSIDE) && !defined(ST_COMPILATION)
#error "Only <st/st.h> can be included directly.h"
#endif
#ifndef __ST_WIDGET_ACCESSIBLE_H__
#define __ST_WIDGET_ACCESSIBLE_H__
G_BEGIN_DECLS
#include <st/st-widget.h>
#include <cally/cally.h>
#define ST_TYPE_WIDGET_ACCESSIBLE st_widget_accessible_get_type ()
#define ST_WIDGET_ACCESSIBLE(obj) \
(G_TYPE_CHECK_INSTANCE_CAST ((obj), \
ST_TYPE_WIDGET_ACCESSIBLE, StWidgetAccessible))
#define ST_IS_WIDGET_ACCESSIBLE(obj) \
(G_TYPE_CHECK_INSTANCE_TYPE ((obj), \
ST_TYPE_WIDGET_ACCESSIBLE))
#define ST_WIDGET_ACCESSIBLE_CLASS(klass) \
(G_TYPE_CHECK_CLASS_CAST ((klass), \
ST_TYPE_WIDGET_ACCESSIBLE, StWidgetAccessibleClass))
#define ST_IS_WIDGET_ACCESSIBLE_CLASS(klass) \
(G_TYPE_CHECK_CLASS_TYPE ((klass), \
ST_TYPE_WIDGET_ACCESSIBLE))
#define ST_WIDGET_ACCESSIBLE_GET_CLASS(obj) \
(G_TYPE_INSTANCE_GET_CLASS ((obj), \
ST_TYPE_WIDGET_ACCESSIBLE, StWidgetAccessibleClass))
typedef struct _StWidgetAccessible StWidgetAccessible;
typedef struct _StWidgetAccessibleClass StWidgetAccessibleClass;
typedef struct _StWidgetAccessiblePrivate StWidgetAccessiblePrivate;
struct _StWidgetAccessible
{
CallyActor parent;
/*< private >*/
StWidgetAccessiblePrivate *priv;
};
struct _StWidgetAccessibleClass
{
CallyActorClass parent_class;
};
GType st_widget_accessible_get_type (void) G_GNUC_CONST;
G_END_DECLS
#endif /* __ST_WIDGET_ACCESSIBLE_H__ */

205
src/st/st-widget.c
View File

@ -42,6 +42,8 @@
#include "st-tooltip.h"
#include "st-theme-node-transition.h"
#include "st-widget-accessible.h"
/*
* Forward declaration for sake of StWidgetChild
*/
@ -67,6 +69,8 @@ struct _StWidgetPrivate
StTooltip *tooltip;
StTextDirection direction;
AtkObject *accessible;
};
/**
@ -117,6 +121,8 @@ static gboolean st_widget_real_navigate_focus (StWidget *widget,
ClutterActor *from,
GtkDirectionType direction);
static AtkObject * st_widget_get_accessible (ClutterActor *actor);
static void
st_widget_set_property (GObject *gobject,
guint prop_id,
@ -281,6 +287,12 @@ st_widget_dispose (GObject *gobject)
priv->tooltip = NULL;
}
/* The real dispose of this accessible is done on
* AtkGObjectAccessible weak ref callback
*/
if (priv->accessible)
priv->accessible = NULL;
G_OBJECT_CLASS (st_widget_parent_class)->dispose (gobject);
}
@ -725,8 +737,11 @@ st_widget_class_init (StWidgetClass *klass)
actor_class->key_focus_out = st_widget_key_focus_out;
actor_class->hide = st_widget_hide;
actor_class->get_accessible = st_widget_get_accessible;
klass->style_changed = st_widget_real_style_changed;
klass->navigate_focus = st_widget_real_navigate_focus;
klass->get_accessible_type = st_widget_accessible_get_type;
/**
* StWidget:pseudo-class:
@ -1948,3 +1963,193 @@ st_get_slow_down_factor ()
{
return st_slow_down_factor;
}
/******************************************************************************/
/*************************** ACCESSIBILITY SUPPORT ****************************/
/******************************************************************************/
/* GObject */
static void st_widget_accessible_class_init (StWidgetAccessibleClass *klass);
static void st_widget_accessible_init (StWidgetAccessible *widget);
/* AtkObject */
static AtkStateSet *st_widget_accessible_ref_state_set (AtkObject *obj);
static void st_widget_accessible_initialize (AtkObject *obj,
gpointer data);
/* Private methods */
static void on_pseudo_class_notify (GObject *gobject,
GParamSpec *pspec,
gpointer data);
static void on_can_focus_notify (GObject *gobject,
GParamSpec *pspec,
gpointer data);
static void check_selected (StWidgetAccessible *self,
StWidget *widget);
G_DEFINE_TYPE (StWidgetAccessible, st_widget_accessible, CALLY_TYPE_ACTOR)
#define ST_WIDGET_ACCESSIBLE_GET_PRIVATE(obj) \
(G_TYPE_INSTANCE_GET_PRIVATE ((obj), ST_TYPE_WIDGET_ACCESSIBLE, \
StWidgetAccessiblePrivate))
struct _StWidgetAccessiblePrivate
{
/* Cached values (used to avoid extra notifications) */
gboolean selected;
};
static AtkObject *
st_widget_get_accessible (ClutterActor *actor)
{
StWidget *widget = NULL;
g_return_val_if_fail (ST_IS_WIDGET (actor), NULL);
widget = ST_WIDGET (actor);
if (widget->priv->accessible == NULL)
{
widget->priv->accessible =
g_object_new (ST_WIDGET_GET_CLASS (widget)->get_accessible_type (),
NULL);
atk_object_initialize (widget->priv->accessible, actor);
}
return widget->priv->accessible;
}
static void
st_widget_accessible_class_init (StWidgetAccessibleClass *klass)
{
GObjectClass *gobject_class = G_OBJECT_CLASS (klass);
AtkObjectClass *atk_class = ATK_OBJECT_CLASS (klass);
atk_class->ref_state_set = st_widget_accessible_ref_state_set;
atk_class->initialize = st_widget_accessible_initialize;
g_type_class_add_private (gobject_class, sizeof (StWidgetAccessiblePrivate));
}
static void
st_widget_accessible_init (StWidgetAccessible *self)
{
StWidgetAccessiblePrivate *priv = ST_WIDGET_ACCESSIBLE_GET_PRIVATE (self);
self->priv = priv;
}
static void
st_widget_accessible_initialize (AtkObject *obj,
gpointer data)
{
ATK_OBJECT_CLASS (st_widget_accessible_parent_class)->initialize (obj, data);
g_signal_connect (data, "notify::pseudo-class",
G_CALLBACK (on_pseudo_class_notify),
obj);
g_signal_connect (data, "notify::can-focus",
G_CALLBACK (on_can_focus_notify),
obj);
/* Check the cached selected state and notify the first selection.
* Ie: it is required to ensure a first notification when Alt+Tab
* popup appears
*/
check_selected (ST_WIDGET_ACCESSIBLE (obj), ST_WIDGET (data));
}
static AtkStateSet *
st_widget_accessible_ref_state_set (AtkObject *obj)
{
AtkStateSet *result = NULL;
ClutterActor *actor = NULL;
StWidget *widget = NULL;
StWidgetAccessible *self = NULL;
result = ATK_OBJECT_CLASS (st_widget_accessible_parent_class)->ref_state_set (obj);
actor = CLUTTER_ACTOR (atk_gobject_accessible_get_object (ATK_GOBJECT_ACCESSIBLE (obj)));
if (actor == NULL) /* State is defunct */
return result;
widget = ST_WIDGET (actor);
self = ST_WIDGET_ACCESSIBLE (obj);
/* priv->selected should be properly updated on the
* ATK_STATE_SELECTED notification callbacks
*/
if (self->priv->selected)
atk_state_set_add_state (result, ATK_STATE_SELECTED);
/* On clutter there isn't any tip to know if a actor is focusable or
* not, anyone can receive the key_focus. For this reason
* cally_actor sets any actor as FOCUSABLE. This is not the case on
* St, where we have can_focus. But this means that we need to
* remove the state FOCUSABLE if it is not focusable
*/
if (st_widget_get_can_focus (widget))
atk_state_set_add_state (result, ATK_STATE_FOCUSABLE);
else
atk_state_set_remove_state (result, ATK_STATE_FOCUSABLE);
return result;
}
static void
on_pseudo_class_notify (GObject *gobject,
GParamSpec *pspec,
gpointer data)
{
check_selected (ST_WIDGET_ACCESSIBLE (data),
ST_WIDGET (gobject));
}
/*
* This method checks if the widget is selected, and notify a atk
* state change if required
*
* In order to decide if there was a selection, we use the current
* pseudo-class of the widget searching for "selected", the current
* homogeneus way to check if a item is selected (see bug 637830)
*
* In a ideal world we would have a more standard way to check if the
* item is selected or not, like the widget-context (as in the case of
* gtktreeview-cells), or something like the property "can-focus". But
* for the moment this is enough, and we can update that in the future
* if required.
*/
static void
check_selected (StWidgetAccessible *self,
StWidget *widget)
{
gboolean found = FALSE;
found = st_widget_has_style_pseudo_class (widget,
"selected");
if (found != self->priv->selected)
{
self->priv->selected = found;
atk_object_notify_state_change (ATK_OBJECT (self),
ATK_STATE_SELECTED,
found);
}
}
static void
on_can_focus_notify (GObject *gobject,
GParamSpec *pspec,
gpointer data)
{
gboolean can_focus = st_widget_get_can_focus (ST_WIDGET (gobject));
atk_object_notify_state_change (ATK_OBJECT (data),
ATK_STATE_FOCUSABLE, can_focus);
}

2
src/st/st-widget.h
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@ -82,6 +82,8 @@ struct _StWidgetClass
gboolean (* navigate_focus) (StWidget *self,
ClutterActor *from,
GtkDirectionType direction);
GType (*get_accessible_type) (void);
};
GType st_widget_get_type (void) G_GNUC_CONST;