gecko-dev/accessible/interfaces/nsIAccessible.idl

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "nsISupports.idl"
#include "nsIArray.idl"

interface nsIPersistentProperties;
interface nsIDOMCSSPrimitiveValue;
interface nsIDOMNode;
interface nsIAccessibleDocument;
interface nsIAccessibleRelation;

/**
 * A cross-platform interface that supports platform-specific 
 * accessibility APIs like MSAA and ATK. Contains the sum of what's needed
 * to support IAccessible as well as ATK's generic accessibility objects.
 * Can also be used by in-process accessibility clients to get information
 * about objects in the accessible tree. The accessible tree is a subset of 
 * nodes in the DOM tree -- such as documents, focusable elements and text.
 * Mozilla creates the implementations of nsIAccessible on demand.
 * See http://www.mozilla.org/projects/ui/accessibility for more information.
 */
[scriptable, uuid(ee62158b-bb83-424b-a88d-d7d7f9cf460d)]
interface nsIAccessible : nsISupports
{
  /**
   * Parent node in accessible tree.
   */
  readonly attribute nsIAccessible parent;

  /**
   * Next sibling in accessible tree
   */
  readonly attribute nsIAccessible nextSibling;

  /**
   * Previous sibling in accessible tree
   */
  readonly attribute nsIAccessible previousSibling;

  /**
   * First child in accessible tree
   */
  readonly attribute nsIAccessible firstChild;

  /**
   * Last child in accessible tree
   */
  readonly attribute nsIAccessible lastChild;
  
  /**
   * Array of all this element's children.
   */
  readonly attribute nsIArray children;

  /**
   * Number of accessible children
   */
  readonly attribute long childCount;

  /**
   * The 0-based index of this accessible in its parent's list of children,
   * or -1 if this accessible does not have a parent.
   */
  readonly attribute long indexInParent;

  /**
   * The DOM node this nsIAccessible is associated with.
   */
  readonly attribute nsIDOMNode DOMNode;

  /**
   * The document accessible that this access node resides in.
   */
  readonly attribute nsIAccessibleDocument document;

  /**
   * The root document accessible that this access node resides in.
   */
  readonly attribute nsIAccessibleDocument rootDocument;

  /**
   * The language for the current DOM node, e.g. en, de, etc.
   */
  readonly attribute DOMString language;

  /**
   * Accessible name -- the main text equivalent for this node. The name is
   * specified by ARIA or by native markup. Example of ARIA markup is
   * aria-labelledby attribute placed on element of this accessible. Example
   * of native markup is HTML label linked with HTML element of this accessible.
   *
   * Value can be string or null. A null value indicates that AT may attempt to
   * compute the name. Any string value, including the empty string, should be
   * considered author-intentional, and respected.
   */
  attribute AString name;

  /**
   * Accessible value -- a number or a secondary text equivalent for this node
   * Widgets that use role attribute can force a value using the valuenow attribute
   */
  readonly attribute AString value;

  /**
   * Accessible description -- long text associated with this node
   */
  readonly attribute AString description;

  /**
   * Provides localized string of accesskey name, such as Alt+D.
   * The modifier may be affected by user and platform preferences.
   * Usually alt+letter, or just the letter alone for menu items. 
   */
  readonly attribute AString accessKey;

  /**
   * Provides localized string of global keyboard accelerator for default
   * action, such as Ctrl+O for Open file
   */
  readonly attribute AString keyboardShortcut;

  /**
   * Enumerated accessible role (see the constants defined in nsIAccessibleRole).
   *
   * @note  The values might depend on platform because of variations. Widgets
   *        can use ARIA role attribute to force the final role.
   */
  readonly attribute unsigned long role;

  /**
   * Accessible states -- bit fields which describe boolean properties of node.
   * Many states are only valid given a certain role attribute that supports
   * them.
   *
   * @param aState - the first bit field (see nsIAccessibleStates::STATE_*
   *                 constants)
   * @param aExtraState - the second bit field
   *                      (see nsIAccessibleStates::EXT_STATE_* constants)
   */
  void getState(out unsigned long aState, out unsigned long aExtraState);

  /**
   * Help text associated with node
   */
  readonly attribute AString help;

  /**
   * Focused accessible child of node
   */
  readonly attribute nsIAccessible focusedChild;

  /**
   * Attributes of accessible
   */
  readonly attribute nsIPersistentProperties attributes;

  /**
   * Returns grouping information. Used for tree items, list items, tab panel
   * labels, radio buttons, etc. Also used for collectons of non-text objects.
   *
   * @param groupLevel - 1-based, similar to ARIA 'level' property
   * @param similarItemsInGroup - 1-based, similar to ARIA 'setsize' property,
   *                              inclusive of the current item
   * @param positionInGroup - 1-based, similar to ARIA 'posinset' property
   */
  [binaryname(ScriptableGroupPosition)]
  void groupPosition(out long aGroupLevel, out long aSimilarItemsInGroup,
                     out long aPositionInGroup);

  /**
   * Accessible child which contains the coordinate at (x, y) in screen pixels.
   * If the point is in the current accessible but not in a child, the
   * current accessible will be returned.
   * If the point is in neither the current accessible or a child, then
   * null will be returned.
   *
   * @param x  screen's x coordinate
   * @param y  screen's y coordinate
   * @return   the deepest accessible child containing the given point
   */
  nsIAccessible getChildAtPoint(in long x, in long y);

  /**
   * Deepest accessible child which contains the coordinate at (x, y) in screen
   * pixels. If the point is in the current accessible but not in a child, the
   * current accessible will be returned. If the point is in neither the current
   * accessible or a child, then null will be returned.
   *
   * @param x  screen's x coordinate
   * @param y  screen's y coordinate
   * @return   the deepest accessible child containing the given point
   */
  nsIAccessible getDeepestChildAtPoint(in long x, in long y);

  /**
   * Nth accessible child using zero-based index or last child if index less than zero
   */
  nsIAccessible getChildAt(in long aChildIndex);

  /**
   * Return accessible relation by the given relation type (see.
   * constants defined in nsIAccessibleRelation).
   */
  nsIAccessibleRelation getRelationByType(in unsigned long aRelationType);

  /**
   * Returns multiple accessible relations for this object.
   */
  nsIArray getRelations();

  /**
   * Return accessible's x and y coordinates relative to the screen and
   * accessible's width and height.
   */
  void getBounds(out long x, out long y, out long width, out long height);

  /**
   * Add or remove this accessible to the current selection
   */
  void setSelected(in boolean isSelected);

  /**
   * Extend the current selection from its current accessible anchor node
   * to this accessible
   */
  void extendSelection();

  /**
   * Select this accessible node only
   */
  void takeSelection();

  /**
   * Focus this accessible node,
   * The state STATE_FOCUSABLE indicates whether this node is normally focusable.
   * It is the callers responsibility to determine whether this node is focusable.
   * accTakeFocus on a node that is not normally focusable (such as a table),
   * will still set focus on that node, although normally that will not be visually 
   * indicated in most style sheets.
   */
  void takeFocus();

  /**
   * The number of accessible actions associated with this accessible
   */
  readonly attribute uint8_t actionCount;

  /**
   * The name of the accessible action at the given zero-based index
   */
  AString getActionName(in uint8_t index);

  /**
   * The description of the accessible action at the given zero-based index
   */
  AString getActionDescription(in uint8_t aIndex);

  /**
   * Perform the accessible action at the given zero-based index
   * Action number 0 is the default action
   */
  void doAction(in uint8_t index);   

  /**
   * Makes an object visible on screen.
   *
   * @param scrollType - defines where the object should be placed on
   *                     the screen (see nsIAccessibleScrollType for
   *                     available constants).
   */
  void scrollTo(in unsigned long aScrollType);

  /**
   * Moves the top left of an object to a specified location.
   *
   * @param coordinateType [in] - specifies whether the coordinates are relative to
   *                         the screen or the parent object (for available
   *                         constants refer to nsIAccessibleCoordinateType)
   * @param x [in] - defines the x coordinate
   * @param y [in] - defines the y coordinate
  */
  void scrollToPoint(in unsigned long coordinateType, in long x, in long y);

  /**
   * Get a pointer to accessibility interface for this node, which is specific 
   * to the OS/accessibility toolkit we're running on.
   */
  [noscript] void getNativeInterface(out voidPtr aOutAccessible);
};