eel-accessibility.c

/* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 8; tab-width: 8 -*- */
/* eel-accessibility.h - Utility functions for accessibility

   Copyright (C) 2002 Anders Carlsson, Sun Microsystems, Inc.

   The Eel Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The Eel Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the Eel Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
   Boston, MA 02110-1301, USA.

   Authors:
	Anders Carlsson <andersca@gnu.org>
	Michael Meeks   <michael@ximian.com>
*/
#include <config.h>
#include <gtk/gtk.h>
#include <atk/atkrelationset.h>
#include <eel/eel-accessibility.h>

void
eel_accessibility_set_up_label_widget_relation (GtkWidget *label, GtkWidget *widget)
{
    AtkObject *atk_widget, *atk_label;

    atk_label = gtk_widget_get_accessible (label);
    atk_widget = gtk_widget_get_accessible (widget);

    /* Create the label -> widget relation */
    atk_object_add_relationship (atk_label, ATK_RELATION_LABEL_FOR, atk_widget);

    /* Create the widget -> label relation */
    atk_object_add_relationship (atk_widget, ATK_RELATION_LABELLED_BY, atk_label);
}

/*
 * Hacks to make re-using gail somewhat easier.
 */

/**
 * eel_accessibility_create_derived_type:
 * @type_name: the name for the new accessible type eg. CajaIconCanvasItemAccessible
 * @existing_gobject_with_proxy: the GType of an object that has a registered factory that
 *      manufactures the type we want to inherit from. ie. to inherit from a GailCanvasItem
 *      we need to pass MATE_TYPE_CANVAS_ITEM - since GailCanvasItem is registered against
 *      that type.
 * @opt_gail_parent_class: the name of the Gail class to derive from eg. GailCanvasItem
 * @class_init: the init function to run for this class
 *
 * This should be run to register the type, it can subsequently be run with
 * the same name and will not re-register it, but simply return it.
 *
 * NB. to do instance init, you prolly want to override AtkObject::initialize
 *
 * Return value: the registered type, or 0 on failure.
 **/
GType
eel_accessibility_create_derived_type (const char *type_name,
                                       GType existing_gobject_with_proxy,
                                       EelAccessibilityClassInitFn class_init)
{
    GType type;
    GType parent_atk_type;
    GTypeInfo tinfo = { 0 };
    GTypeQuery query;
    AtkObjectFactory *factory;

    if ((type = g_type_from_name (type_name)))
    {
        return type;
    }

    factory = atk_registry_get_factory
              (atk_get_default_registry (),
               existing_gobject_with_proxy);
    if (!factory)
    {
        return G_TYPE_INVALID;
    }

    parent_atk_type = atk_object_factory_get_accessible_type (factory);
    if (!parent_atk_type)
    {
        return G_TYPE_INVALID;
    }

    /*
     * Figure out the size of the class and instance
     * we are deriving from
     */
    g_type_query (parent_atk_type, &query);

    if (class_init)
    {
        tinfo.class_init = (GClassInitFunc) class_init;
    }

    tinfo.class_size    = query.class_size;
    tinfo.instance_size = query.instance_size;

    /* Register the type */
    type = g_type_register_static (
               parent_atk_type, type_name, &tinfo, 0);

    return type;
}


static GQuark
get_quark_accessible (void)
{
    static GQuark quark_accessible_object = 0;

    if (!quark_accessible_object)
    {
        quark_accessible_object = g_quark_from_static_string
                                  ("accessible-object");
    }

    return quark_accessible_object;
}

static GQuark
get_quark_gobject (void)
{
    static GQuark quark_accessible_gobject = 0;

    if (!quark_accessible_gobject)
    {
        quark_accessible_gobject = g_quark_from_static_string
                                   ("object-for-accessible");
    }

    return quark_accessible_gobject;
}

/**
 * eel_accessibility_get_atk_object:
 * @object: a GObject of some sort
 *
 * gets an AtkObject associated with a GObject
 *
 * Return value: the associated accessible if one exists or NULL
 **/
AtkObject *
eel_accessibility_get_atk_object (gpointer object)
{
    return g_object_get_qdata (object, get_quark_accessible ());
}

/**
 * eel_accessibilty_for_object:
 * @object: a GObject of some sort
 *
 * gets an AtkObject associated with a GObject and if it doesn't
 * exist creates a suitable accessible object.
 *
 * Return value: an associated accessible.
 **/
AtkObject *
eel_accessibility_for_object (gpointer object)
{
    if (GTK_IS_WIDGET (object))
        return gtk_widget_get_accessible (object);

    return atk_gobject_accessible_for_object (object);
}

/**
 * eel_accessibility_get_gobject:
 * @object: an AtkObject
 *
 * gets the GObject associated with the AtkObject, for which
 * @object provides accessibility support.
 *
 * Return value: the accessible's associated GObject
 **/
gpointer
eel_accessibility_get_gobject (AtkObject *object)
{
    return g_object_get_qdata (G_OBJECT (object), get_quark_gobject ());
}

static void
eel_accessibility_destroy (gpointer data,
                           GObject *where_the_object_was)
{
    atk_object_notify_state_change
    (ATK_OBJECT (data), ATK_STATE_DEFUNCT, TRUE);
}

/**
 * eel_accessibility_set_atk_object_return:
 * @object: a GObject
 * @atk_object: it's AtkObject
 *
 * used to register and return a new accessible object for something
 *
 * Return value: @atk_object.
 **/
AtkObject *
eel_accessibility_set_atk_object_return (gpointer   object,
        AtkObject *atk_object)
{
    atk_object_initialize (atk_object, object);

    if (!ATK_IS_GOBJECT_ACCESSIBLE (atk_object))
    {
        g_object_set_qdata_full
        (object, get_quark_accessible (), atk_object,
         (GDestroyNotify)eel_accessibility_destroy);
        g_object_set_qdata
        (G_OBJECT (atk_object), get_quark_gobject (), object);
    }

    return atk_object;
}

static GailTextUtil *
get_simple_text (gpointer object)
{
    GObject *gobject;
    EelAccessibleTextIface *aif;

    if (GTK_IS_ACCESSIBLE (object))
    {
        gobject = G_OBJECT (gtk_accessible_get_widget (GTK_ACCESSIBLE (object)));
    }
    else
    {
        gobject = eel_accessibility_get_gobject (object);
    }

    if (!gobject)
    {
        return NULL;
    }

    aif = EEL_ACCESSIBLE_TEXT_GET_IFACE (gobject);
    if (!aif)
    {
        g_warning ("No accessible text inferface on '%s'",
                   g_type_name_from_instance ((gpointer) gobject));

    }
    else if (aif->get_text)
    {
        return aif->get_text (gobject);
    }

    return NULL;
}

char *
eel_accessibility_text_get_text (AtkText *text,
                                 gint     start_pos,
                                 gint     end_pos)
{
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, NULL);

    return gail_text_util_get_substring (util, start_pos, end_pos);
}

gunichar
eel_accessibility_text_get_character_at_offset (AtkText *text,
        gint     offset)
{
    char *txt, *index;
    gint sucks1 = 0, sucks2 = -1;
    gunichar c;
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, 0);

    txt = gail_text_util_get_substring (util, sucks1, sucks2);

    index = g_utf8_offset_to_pointer (txt, offset);
    c = g_utf8_get_char (index);
    g_free (txt);

    return c;
}

char *
eel_accessibility_text_get_text_before_offset (AtkText	      *text,
        gint            offset,
        AtkTextBoundary boundary_type,
        gint           *start_offset,
        gint           *end_offset)
{
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, NULL);

    return gail_text_util_get_text (
               util, NULL, GAIL_BEFORE_OFFSET,
               boundary_type, offset, start_offset, end_offset);
}

char *
eel_accessibility_text_get_text_at_offset (AtkText        *text,
        gint            offset,
        AtkTextBoundary boundary_type,
        gint           *start_offset,
        gint           *end_offset)
{
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, NULL);

    return gail_text_util_get_text (
               util, NULL, GAIL_AT_OFFSET,
               boundary_type, offset, start_offset, end_offset);
}

gchar*
eel_accessibility_text_get_text_after_offset  (AtkText	      *text,
        gint            offset,
        AtkTextBoundary boundary_type,
        gint           *start_offset,
        gint           *end_offset)
{
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, NULL);

    return gail_text_util_get_text (
               util, NULL, GAIL_AFTER_OFFSET,
               boundary_type, offset, start_offset, end_offset);
}

gint
eel_accessibility_text_get_character_count (AtkText *text)
{
    GailTextUtil *util = get_simple_text (text);
    g_return_val_if_fail (util != NULL, -1);

    return gtk_text_buffer_get_char_count (util->buffer);
}

static void
eel_accessibility_simple_text_interface_init (AtkTextIface *iface)
{
    iface->get_text                = eel_accessibility_text_get_text;
    iface->get_character_at_offset = eel_accessibility_text_get_character_at_offset;
    iface->get_text_before_offset  = eel_accessibility_text_get_text_before_offset;
    iface->get_text_at_offset      = eel_accessibility_text_get_text_at_offset;
    iface->get_text_after_offset   = eel_accessibility_text_get_text_after_offset;
    iface->get_character_count     = eel_accessibility_text_get_character_count;

    /*	iface->get_caret_offset = eel_accessibility_text_get_caret_offset;
    	iface->set_caret_offset = eel_accessibility_text_set_caret_offset;
    	iface->get_selection = eel_accessibility_text_get_selection;
    	iface->get_n_selections = eel_accessibility_text_get_n_selections;
    	iface->add_selection = eel_accessibility_text_add_selection;
    	iface->remove_selection = eel_accessibility_text_remove_selection;
    	iface->set_selection = eel_accessibility_text_set_selection;
    	iface->get_run_attributes = eel_accessibility_text_get_run_attributes;
    	iface->get_default_attributes = eel_accessibility_text_get_default_attributes;
    	iface->get_character_extents = eel_accessibility_text_get_character_extents;
    	iface->get_offset_at_point = eel_accessibility_text_get_offset_at_point; */
}

void
eel_accessibility_add_simple_text (GType type)
{
    const GInterfaceInfo simple_text_info =
    {
        (GInterfaceInitFunc)
        eel_accessibility_simple_text_interface_init,
        (GInterfaceFinalizeFunc) NULL,
        NULL
    };

    g_return_if_fail (type != G_TYPE_INVALID);

    g_type_add_interface_static (
        type, ATK_TYPE_TEXT, &simple_text_info);
}

GType
eel_accessible_text_get_type (void)
{
    static GType type = 0;

    if (!type)
    {
        const GTypeInfo tinfo =
        {
            sizeof (AtkTextIface),
            (GBaseInitFunc) NULL,
            (GBaseFinalizeFunc) NULL,
            (GClassInitFunc) NULL,
            (GClassFinalizeFunc) NULL
        };

        type = g_type_register_static (
                   G_TYPE_INTERFACE, "EelAccessibleText", &tinfo, 0);
    }

    return type;
}

void
eel_accessibility_set_name (gpointer    object,
                            const char *name)
{
    AtkObject *atk_object = eel_accessibility_for_object (object);

    if (atk_object)
    {
        atk_object_set_name (atk_object, name);
    }
}

void
eel_accessibility_set_description (gpointer    object,
                                   const char *description)
{
    AtkObject *atk_object = eel_accessibility_for_object (object);

    if (atk_object)
    {
        atk_object_set_description (atk_object, description);
    }
}