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