atk/atkobject.h

   1 /* ATK -  Accessibility Toolkit
   2  * Copyright 2001 Sun Microsystems Inc.
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 #ifndef __ATK_OBJECT_H__
  21 #define __ATK_OBJECT_H__
  22
  23 #ifdef __cplusplus
  24 extern "C" {
  25 #endif /* __cplusplus */
  26
  27 #include <glib-object.h>
  28 #include <atk/atkstate.h>
  29
  30 /*
  31  * AtkObject represents the minimum information all accessible objects
  32  * return. This information includes accessible name, accessible
  33  * description, role and state of the object, as well information about
  34  * its parent and children. It is also possible to obtain more specific
  35  * accessibility information about a component if it supports one or more
  36  * of the following interfaces:
  37  */
  38
  39
  40 /**
  41  *AtkRole:
  42  *@ATK_ROLE_INVALID: Invalid role
  43  *@ATK_ROLE_ACCEL_LABEL: A label which represents an accelerator
  44  *@ATK_ROLE_ALERT: An object which is an alert to the user
  45  *@ATK_ROLE_ANIMATION: An object which is an animated image
  46  *@ATK_ROLE_ARROW: An arrow in one of the four cardinal directions
  47  *@ATK_ROLE_CALENDAR:  An object that displays a calendar and allows the user to select a date
  48  *@ATK_ROLE_CANVAS: An object that can be drawn into and is used to trap events
  49  *@ATK_ROLE_CHECK_BOX: A choice that can be checked or unchecked and provides a separate indicator for the current state
  50  *@ATK_ROLE_CHECK_MENU_ITEM: A menu item with a check box
  51  *@ATK_ROLE_COLOR_CHOOSER: A specialized dialog that lets the user choose a color
  52  *@ATK_ROLE_COLUMN_HEADER: The header for a column of data
  53  *@ATK_ROLE_COMBO_BOX: A list of choices the user can select from
  54  *@ATK_ROLE_DATE_EDITOR: An object whose purpose is to allow a user to edit a date
  55  *@ATK_ROLE_DESKTOP_ICON: An inconifed internal frame within a DESKTOP_PANE
  56  *@ATK_ROLE_DESKTOP_FRAME: A pane that supports internal frames and iconified versions of those internal frames
  57  *@ATK_ROLE_DIAL: An object whose purpose is to allow a user to set a value
  58  *@ATK_ROLE_DIALOG: A top level window with title bar and a border
  59  *@ATK_ROLE_DIRECTORY_PANE: A pane that allows the user to navigate through and select the contents of a directory
  60  *@ATK_ROLE_DRAWING_AREA: An object used for drawing custom user interface elements
  61  *@ATK_ROLE_FILE_CHOOSER: A specialized dialog that lets the user choose a file
  62  *@ATK_ROLE_FILLER: A object that fills up space in a user interface
  63  *@ATK_ROLE_FONT_CHOOSER: A specialized dialog that lets the user choose a font
  64  *@ATK_ROLE_FRAME: A top level window with a title bar, border, menubar, etc.
  65  *@ATK_ROLE_GLASS_PANE: A pane that is guaranteed to be painted on top of all panes beneath it
  66  *@ATK_ROLE_HTML_CONTAINER: A document container for HTML, whose children represent the document content
  67  *@ATK_ROLE_ICON: A small fixed size picture, typically used to decorate components
  68  *@ATK_ROLE_IMAGE: An object whose primary purpose is to display an image
  69  *@ATK_ROLE_INTERNAL_FRAME: A frame-like object that is clipped by a desktop pane
  70  *@ATK_ROLE_LABEL: An object used to present an icon or short string in an interface
  71  *@ATK_ROLE_LAYERED_PANE: A specialized pane that allows its children to be drawn in layers, providing a form of stacking order
  72  *@ATK_ROLE_LIST: An object that presents a list of objects to the user and allows the user to select one or more of them
  73  *@ATK_ROLE_LIST_ITEM: An object that represents an element of a list
  74  *@ATK_ROLE_MENU: An object usually found inside a menu bar that contains a list of actions the user can choose from
  75  *@ATK_ROLE_MENU_BAR: An object usually drawn at the top of the primary dialog box of an application that contains a list of menus the user can choose from
  76  *@ATK_ROLE_MENU_ITEM: An object usually contained in a menu that presents an action the user can choose
  77  *@ATK_ROLE_OPTION_PANE: A specialized pane whose primary use is inside a DIALOG
  78  *@ATK_ROLE_PAGE_TAB: An object that is a child of a page tab list
  79  *@ATK_ROLE_PAGE_TAB_LIST: An object that presents a series of panels (or page tabs), one at a time, through some mechanism provided by the object
  80  *@ATK_ROLE_PANEL: A generic container that is often used to group objects
  81  *@ATK_ROLE_PASSWORD_TEXT: A text object uses for passwords, or other places where the text content is not shown visibly to the user
  82  *@ATK_ROLE_POPUP_MENU: A temporary window that is usually used to offer the user a list of choices, and then hides when the user selects one of those choices
  83  *@ATK_ROLE_PROGRESS_BAR: An object used to indicate how much of a task has been completed
  84  *@ATK_ROLE_PUSH_BUTTON: An object the user can manipulate to tell the application to do something
  85  *@ATK_ROLE_RADIO_BUTTON: A specialized check box that will cause other radio buttons in the same group to become unchecked when this one is checked
  86  *@ATK_ROLE_RADIO_MENU_ITEM: A check menu item which belongs to a group. At each instant exactly one of the radio menu items from a group is selected
  87  *@ATK_ROLE_ROOT_PANE: A specialized pane that has a glass pane and a layered pane as its children
  88  *@ATK_ROLE_ROW_HEADER: The header for a row of data
  89  *@ATK_ROLE_SCROLL_BAR: An object usually used to allow a user to incrementally view a large amount of data.
  90  *@ATK_ROLE_SCROLL_PANE: An object that allows a user to incrementally view a large amount of information
  91  *@ATK_ROLE_SEPARATOR: An object usually contained in a menu to provide a visible and logical separation of the contents in a menu
  92  *@ATK_ROLE_SLIDER: An object that allows the user to select from a bounded range
  93  *@ATK_ROLE_SPLIT_PANE: A specialized panel that presents two other panels at the same time
  94  *@ATK_ROLE_SPIN_BUTTON: An object used to get an integer or floating point number from the user
  95  *@ATK_ROLE_STATUSBAR: An object which reports messages of minor importance to the user
  96  *@ATK_ROLE_TABLE: An object used to represent information in terms of rows and columns
  97  *@ATK_ROLE_TABLE_CELL: A cell in a table
  98  *@ATK_ROLE_TABLE_COLUMN_HEADER: The header for a column of a table
  99  *@ATK_ROLE_TABLE_ROW_HEADER: The header for a row of a table
 100  *@ATK_ROLE_TEAR_OFF_MENU_ITEM: A menu item used to tear off and reattach its menu
 101  *@ATK_ROLE_TERMINAL: An object that represents an accessible terminal
 102  *@ATK_ROLE_TEXT: An object that presents text to the user
 103  *@ATK_ROLE_TOGGLE_BUTTON: A specialized push button that can be checked or unchecked, but does not provide a separate indicator for the current state
 104  *@ATK_ROLE_TOOL_BAR: A bar or palette usually composed of push buttons or toggle buttons
 105  *@ATK_ROLE_TOOL_TIP: An object that provides information about another object
 106  *@ATK_ROLE_TREE: An object used to represent hierarchical information to the user
 107  *@ATK_ROLE_TREE_TABLE: An object capable of expanding and collapsing rows as well as showing multiple columns of data
 108  *@ATK_ROLE_UNKNOWN: The object contains some Accessible information, but its role is not known
 109  *@ATK_ROLE_VIEWPORT: An object usually used in a scroll pane
 110  *@ATK_ROLE_WINDOW: A top level window with no title or border
 111  *@ATK_ROLE_LAST_DEFINED: not a valid role, used for finding end of enumeration
 112  *
 113  *Describes the role of an object
 114  **/
 115 typedef enum
 116 {
 117   ATK_ROLE_INVALID,
 118   ATK_ROLE_ACCEL_LABEL,
 119   ATK_ROLE_ALERT,
 120   ATK_ROLE_ANIMATION,
 121   ATK_ROLE_ARROW,
 122   ATK_ROLE_CALENDAR,
 123   ATK_ROLE_CANVAS,
 124   ATK_ROLE_CHECK_BOX,
 125   ATK_ROLE_CHECK_MENU_ITEM,
 126   ATK_ROLE_COLOR_CHOOSER,
 127   ATK_ROLE_COLUMN_HEADER,
 128   ATK_ROLE_COMBO_BOX,
 129   ATK_ROLE_DATE_EDITOR,
 130   ATK_ROLE_DESKTOP_ICON,
 131   ATK_ROLE_DESKTOP_FRAME,
 132   ATK_ROLE_DIAL,
 133   ATK_ROLE_DIALOG,
 134   ATK_ROLE_DIRECTORY_PANE,
 135   ATK_ROLE_DRAWING_AREA,
 136   ATK_ROLE_FILE_CHOOSER,
 137   ATK_ROLE_FILLER,
 138   ATK_ROLE_FONT_CHOOSER,
 139   ATK_ROLE_FRAME,
 140   ATK_ROLE_GLASS_PANE,
 141   ATK_ROLE_HTML_CONTAINER,
 142   ATK_ROLE_ICON,
 143   ATK_ROLE_IMAGE,
 144   ATK_ROLE_INTERNAL_FRAME,
 145   ATK_ROLE_LABEL,
 146   ATK_ROLE_LAYERED_PANE,
 147   ATK_ROLE_LIST,
 148   ATK_ROLE_LIST_ITEM,
 149   ATK_ROLE_MENU,
 150   ATK_ROLE_MENU_BAR,
 151   ATK_ROLE_MENU_ITEM,
 152   ATK_ROLE_OPTION_PANE,
 153   ATK_ROLE_PAGE_TAB,
 154   ATK_ROLE_PAGE_TAB_LIST,
 155   ATK_ROLE_PANEL,
 156   ATK_ROLE_PASSWORD_TEXT,
 157   ATK_ROLE_POPUP_MENU,
 158   ATK_ROLE_PROGRESS_BAR,
 159   ATK_ROLE_PUSH_BUTTON,
 160   ATK_ROLE_RADIO_BUTTON,
 161   ATK_ROLE_RADIO_MENU_ITEM,
 162   ATK_ROLE_ROOT_PANE,
 163   ATK_ROLE_ROW_HEADER,
 164   ATK_ROLE_SCROLL_BAR,
 165   ATK_ROLE_SCROLL_PANE,
 166   ATK_ROLE_SEPARATOR,
 167   ATK_ROLE_SLIDER,
 168   ATK_ROLE_SPLIT_PANE,
 169   ATK_ROLE_SPIN_BUTTON,
 170   ATK_ROLE_STATUSBAR,
 171   ATK_ROLE_TABLE,
 172   ATK_ROLE_TABLE_CELL,
 173   ATK_ROLE_TABLE_COLUMN_HEADER,
 174   ATK_ROLE_TABLE_ROW_HEADER,
 175   ATK_ROLE_TEAR_OFF_MENU_ITEM,
 176   ATK_ROLE_TERMINAL,
 177   ATK_ROLE_TEXT,
 178   ATK_ROLE_TOGGLE_BUTTON,
 179   ATK_ROLE_TOOL_BAR,
 180   ATK_ROLE_TOOL_TIP,
 181   ATK_ROLE_TREE,
 182   ATK_ROLE_TREE_TABLE,
 183   ATK_ROLE_UNKNOWN,
 184   ATK_ROLE_VIEWPORT,
 185   ATK_ROLE_WINDOW,
 186   ATK_ROLE_LAST_DEFINED
 187 } AtkRole;
 188
 189 AtkRole                  atk_role_register        (const gchar *name);
 190
 191 /**
 192  *AtkLayer:
 193  *@ATK_LAYER_INVALID: The object does not have a layer
 194  *@ATK_LAYER_BACKGROUND: This layer is reserved for the desktop background
 195  *@ATK_LAYER_CANVAS: This layer is used for Canvas components
 196  *@ATK_LAYER_WIDGET: This layer is normally used for components
 197  *@ATK_LAYER_MDI: This layer is used for layered components
 198  *@ATK_LAYER_POPUP: This layer is used for popup components, such as menus
 199  *@ATK_LAYER_OVERLAY: This layer is reserved for future use.
 200  *
 201  * Describes the layer of a component
 202  **/
 203 typedef enum
 204 {
 205   ATK_LAYER_INVALID,
 206   ATK_LAYER_BACKGROUND,
 207   ATK_LAYER_CANVAS,
 208   ATK_LAYER_WIDGET,
 209   ATK_LAYER_MDI,
 210   ATK_LAYER_POPUP,
 211   ATK_LAYER_OVERLAY
 212 } AtkLayer;
 213
 214 #define ATK_TYPE_OBJECT                           (atk_object_get_type ())
 215 #define ATK_OBJECT(obj)                           (G_TYPE_CHECK_INSTANCE_CAST ((obj), ATK_TYPE_OBJECT, AtkObject))
 216 #define ATK_OBJECT_CLASS(klass)                   (G_TYPE_CHECK_CLASS_CAST ((klass), ATK_TYPE_OBJECT, AtkObjectClass))
 217 #define ATK_IS_OBJECT(obj)                        (G_TYPE_CHECK_INSTANCE_TYPE ((obj), ATK_TYPE_OBJECT))
 218 #define ATK_IS_OBJECT_CLASS(klass)                (G_TYPE_CHECK_CLASS_TYPE ((klass), ATK_TYPE_OBJECT))
 219 #define ATK_OBJECT_GET_CLASS(obj)                 (G_TYPE_INSTANCE_GET_CLASS ((obj), ATK_TYPE_OBJECT, AtkObjectClass))
 220
 221 #define ATK_TYPE_IMPLEMENTOR                      (atk_implementor_get_type ())
 222 #define ATK_IS_IMPLEMENTOR(obj)                   G_TYPE_CHECK_INSTANCE_TYPE ((obj), ATK_TYPE_IMPLEMENTOR)
 223 #define ATK_IMPLEMENTOR(obj)                      G_TYPE_CHECK_INSTANCE_CAST ((obj), ATK_TYPE_IMPLEMENTOR, AtkImplementor)
 224 #define ATK_IMPLEMENTOR_GET_IFACE(obj)            (G_TYPE_INSTANCE_GET_INTERFACE ((obj), ATK_TYPE_IMPLEMENTOR, AtkImplementorIface))
 225
 226
 227 typedef struct _AtkImplementor            AtkImplementor; /* dummy typedef */
 228 typedef struct _AtkImplementorIface       AtkImplementorIface;
 229
 230
 231 typedef struct _AtkObject                 AtkObject;
 232 typedef struct _AtkObjectClass            AtkObjectClass;
 233 typedef struct _AtkRelationSet            AtkRelationSet;
 234 typedef struct _AtkStateSet               AtkStateSet;
 235
 236 struct _AtkPropertyValues
 237 {
 238   const gchar  *property_name;
 239   GValue old_value;
 240   GValue new_value;
 241 };
 242
 243 typedef struct _AtkPropertyValues        AtkPropertyValues;
 244
 245 /*
 246  * For most properties the old_value field of AtkPropertyValues will
 247  * not contain a valid value.
 248  *
 249  * Currently, the only property for which old_value is used is
 250  * accessible-state; for instance if there is a focus state the
 251  * property change handler will be called for the object which lost the focus
 252  * with the old_value containing an AtkState value corresponding to focused
 253  * and the property change handler will be called for the object which
 254  * received the focus with the new_value containing an AtkState value
 255  * corresponding to focused.
 256  */
 257 typedef void (*AtkPropertyChangeHandler) (AtkObject*, AtkPropertyValues*);
 258
 259
 260 struct _AtkObject
 261 {
 262   GObject parent;
 263
 264   gchar *description;
 265   gchar *name;
 266   AtkObject *accessible_parent;
 267   AtkRole role;
 268   AtkRelationSet *relation_set;
 269   AtkLayer layer;
 270 };
 271
 272 struct _AtkObjectClass
 273 {
 274   GObjectClass parent;
 275
 276   /*
 277    * Gets the accessible name of the object
 278    */
 279   G_CONST_RETURN gchar*    (* get_name)            (AtkObject                *accessible);
 280   /*
 281    * Gets the accessible description of the object
 282    */
 283   G_CONST_RETURN gchar*    (* get_description)     (AtkObject                *accessible);
 284   /*
 285    * Gets the accessible parent of the object
 286    */
 287   AtkObject*               (*get_parent)           (AtkObject                *accessible);
 288
 289   /*
 290    * Gets the number of accessible children of the object
 291    */
 292   gint                    (* get_n_children)       (AtkObject                *accessible);
 293   /*
 294    * Returns a reference to the specified accessible child of the object.
 295    * The accessible children are 0-based so the first accessible child is
 296    * at index 0, the second at index 1 and so on.
 297    */
 298   AtkObject*              (* ref_child)            (AtkObject                *accessible,
 299                                                     gint                      i);
 300   /*
 301    * Gets the 0-based index of this object in its parent; returns -1 if the
 302    * object does not have an accessible parent.
 303    */
 304   gint                    (* get_index_in_parent) (AtkObject                 *accessible);
 305   /*
 306    * Gets the RelationSet associated with the object
 307    */
 308   AtkRelationSet*         (* ref_relation_set)    (AtkObject                 *accessible);
 309   /*
 310    * Gets the role of the object
 311    */
 312   AtkRole                 (* get_role)            (AtkObject                 *accessible);
 313   AtkLayer                (* get_layer)           (AtkObject                 *accessible);
 314   gint                    (* get_mdi_zorder)      (AtkObject                 *accessible);
 315   /*
 316    * Gets the state set of the object
 317    */
 318   AtkStateSet*            (* ref_state_set)       (AtkObject                 *accessible);
 319   /*
 320    * Sets the accessible name of the object
 321    */
 322   void                    (* set_name)            (AtkObject                 *accessible,
 323                                                    const gchar               *name);
 324   /*
 325    * Sets the accessible description of the object
 326    */
 327   void                    (* set_description)     (AtkObject                 *accessible,
 328                                                    const gchar               *description);
 329   /*
 330    * Sets the accessible parent of the object
 331    */
 332   void                    (* set_parent)          (AtkObject                 *accessible,
 333                                                    AtkObject                 *parent);
 334   /*
 335    * Sets the accessible role of the object
 336    */
 337   void                    (* set_role)            (AtkObject                 *accessible,
 338                                                    AtkRole                   role);
 339   /*
 340    * Specifies a function to be called when a property changes value
 341    */
 342 guint                     (* connect_property_change_handler)    (AtkObject
 343                  *accessible,
 344                                                                   AtkPropertyChangeHandler       *handler);
 345   /*
 346    * Removes a property change handler which was specified using
 347    * connect_property_change_handler
 348    */
 349 void                      (* remove_property_change_handler)     (AtkObject
 350                 *accessible,
 351                                                                   guint
 352                 handler_id);
 353   /*
 354    * The signal handler which is executed when there is a change in the
 355    * children of the object
 356    */
 357   void                    (* children_changed)    (AtkObject                  *accessible,
 358                                                    gint                       change_index,
 359                                                    AtkObject                  *changed_child);
 360   /*
 361    * The signal handler which is executed  when there is a focus event
 362    * for an object.
 363    */
 364   void                    (*focus_event)          (AtkObject                  *accessible,
 365                                                    gboolean                   focus_in);
 366   /*
 367    * The signal handler which is executed  when there is a property_change
 368    * signal for an object.
 369    */
 370   gint                    (*property_change)      (AtkObject                  *accessible,
 371                                                    AtkPropertyValues          *values);
 372   /*
 373    * The signal handler which is executed  when there is a state_change
 374    * signal for an object.
 375    */
 376   gint                    (*state_change)         (AtkObject                  *accessible,
 377                                                    const gchar                *name,
 378                                                    gboolean                   state_set);
 379   /*
 380    * The signal handler which is executed when there is a change in the
 381    * visible data for an object
 382    */
 383   void                    (*visible_data_changed) (AtkObject                  *accessible);
 384
 385 };
 386
 387 GType            atk_object_get_type   (void);
 388
 389 struct _AtkImplementorIface
 390 {
 391   GTypeInterface parent;
 392
 393   AtkObject*   (*ref_accessible) (AtkImplementor *implementor);
 394 };
 395 GType atk_implementor_get_type (void);
 396
 397 /*
 398  * This method uses the ref_accessible method in AtkImplementorIface,
 399  * if the object's class implements AtkImplementorIface.
 400  * Otherwise it returns %NULL.
 401  *
 402  * IMPORTANT:
 403  * Note also that because this method may return flyweight objects,
 404  * it increments the returned AtkObject's reference count.
 405  * Therefore it is the responsibility of the calling
 406  * program to unreference the object when no longer needed.
 407  * (c.f. gtk_widget_get_accessible() where this is not the case).
 408  */
 409 AtkObject*              atk_implementor_ref_accessible            (AtkImplementor *implementor);
 410
 411 /*
 412  * Properties directly supported by AtkObject
 413  */
 414
 415 G_CONST_RETURN gchar*   atk_object_get_name                       (AtkObject *accessible);
 416 G_CONST_RETURN gchar*   atk_object_get_description                (AtkObject *accessible);
 417 AtkObject*              atk_object_get_parent                     (AtkObject *accessible);
 418 gint                    atk_object_get_n_accessible_children      (AtkObject *accessible);
 419 AtkObject*              atk_object_ref_accessible_child           (AtkObject *accessible,
 420                                                                    gint        i);
 421 AtkRelationSet*         atk_object_ref_relation_set               (AtkObject *accessible);
 422 AtkRole                 atk_object_get_role                       (AtkObject *accessible);
 423 AtkLayer                atk_object_get_layer                      (AtkObject *accessible);
 424 gint                    atk_object_get_mdi_zorder                 (AtkObject *accessible);
 425 AtkStateSet*            atk_object_ref_state_set                  (AtkObject *accessible);
 426 gint                    atk_object_get_index_in_parent            (AtkObject *accessible);
 427 void                    atk_object_set_name                       (AtkObject *accessible,
 428                                                                    const gchar *name);
 429 void                    atk_object_set_description                (AtkObject *accessible,
 430                                                                    const gchar *description);
 431 void                    atk_object_set_parent                     (AtkObject *accessible,
 432                                                                    AtkObject *parent);
 433 void                    atk_object_set_role                       (AtkObject *accessible,
 434                                                                    AtkRole   role);
 435
 436
 437 /*
 438  * to install property change listener, one must
 439  * install signal handler for gobject "properties_changed" signal.
 440  * (for single notifications of multiple changes).
 441  * We could use the "notify" signal instead.
 442  *
 443  */
 444 guint                atk_object_connect_property_change_handler  (AtkObject                      *accessible,
 445                                                                   AtkPropertyChangeHandler       *handler);
 446 void                 atk_object_remove_property_change_handler   (AtkObject                      *accessible,
 447                                                                   guint                          handler_id);
 448
 449 void                 atk_object_notify_state_change              (AtkObject                      *accessible,
 450                                                                   AtkState                       state,
 451                                                                   gboolean                       value);
 452
 453 /*
 454  * Note: the properties which are registered with the GType
 455  *   property registry, for type ATK_TYPE_OBJECT, are as follows:
 456  *
 457  *   "accessible-name"
 458  *   "accessible-description"
 459  *   "accessible-parent"
 460  *   "accessible-child"
 461  *   "accessible-role"
 462  *   "accessible-state"
 463  *   "accessible-parent"
 464  *   "accessible-text"
 465  *   "accessible-caret"
 466  *   "accessible-selection"
 467  *   "accessible-value"
 468  *   "accessible-visible-data"
 469  *   "accessible-table-caption"
 470  *   "accessible-table-column-header"
 471  *   "accessible-table-row-heaer"
 472  *   "accessible-table-summary"
 473  *   "accessible-model"
 474  *
 475  * accessibility property change listeners should use the
 476  *   normal GObject property interfaces and "properties_changed"
 477  *   signal handler semantics to interpret the property change
 478  *   information relayed from AtkObject.
 479  *   (AtkObject instances will connect to the "properties_changed"
 480  *   signal in their host objects, and relay the signals when appropriate).
 481  */
 482
 483 /* For other signals, see related interfaces
 484  *
 485  *    AtkActionIface,
 486  *    AtkComponentIface,
 487  *    AtkHypertextIface,
 488  *    AtkImageIface,
 489  *    AtkSelectionIface,
 490  *    AtkTableIface,
 491  *    AtkTextIface,
 492  *    AtkValueIface.
 493  *
 494  *  The usage model for obtaining these interface instances is:
 495  *    ATK_<interfacename>_GET_IFACE(GObject *accessible),
 496  *    where accessible, though specified as a GObject, is
 497  *    the AtkObject instance being queried.
 498  *  More usually, the interface will be used via a cast to the
 499  *    interface's corresponding "type":
 500  *
 501  *    AtkText textImpl = ATK_TEXT(accessible);
 502  *    if (textImpl)
 503  *      {
 504  *        cpos = atk_text_get_caret_position(textImpl);
 505  *      }
 506  *
 507  *  If it's known in advance that accessible implements AtkTextIface,
 508  *    this is shortened to:
 509  *
 510  *    cpos = atk_text_get_caret_position (ATK_TEXT (accessible));
 511  */
 512
 513 #ifdef __cplusplus
 514 }
 515 #endif /* __cplusplus */
 516
 517
 518 #endif /* __ATK_OBJECT_H__ */