qaccessible.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

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#include "qaccessible.h"

#ifndef QT_NO_ACCESSIBILITY

#include "qaccessibleplugin.h"
#include "qaccessiblewidget.h"
#include "qapplication.h"
#include "qhash.h"
#include "qmetaobject.h"
#include "qmutex.h"
#include <private/qfactoryloader_p.h>

#include "qwidget.h"

/*!
    \class QAccessible
    \brief The QAccessible class provides enums and static functions
    relating to accessibility.

    \ingroup accessibility
    \mainclass

    Accessible applications can be used by people who are not able to
    use applications by conventional means.

    The functions in this class are used for communication between
    accessible applications (also called AT Servers) and
    accessibility tools (AT Clients), such as screen readers and
    braille displays. Clients and servers communicate in the following way:

    \list
    \o  \e{AT Servers} notify the clients about events through calls to the
        updateAccessibility() function.

    \o  \e{AT Clients} request information about the objects in the server.
        The QAccessibleInterface class is the core interface, and encapsulates
        this information in a pure virtual API. Implementations of the interface
        are provided by Qt through the queryAccessibleInterface() API.
    \endlist

    The communication between servers and clients is initialized by
    the setRootObject() function. Function pointers can be installed
    to replace or extend the default behavior of the static functions
    in QAccessible.

    Qt supports Microsoft Active Accessibility (MSAA), Mac OS X
    Accessibility, and the Unix/X11 AT-SPI standard. Other backends
    can be supported using QAccessibilityBridge.

    In addition to QAccessible's static functions, Qt offers one
    generic interface, QAccessibleInterface, that can be used to wrap
    all widgets and objects (e.g., QPushButton). This single
    interface provides all the metadata necessary for the assistive
    technologies. Qt provides implementations of this interface for
    its built-in widgets as plugins.

    When you develop custom widgets, you can create custom subclasses
    of QAccessibleInterface and distribute them as plugins (using
    QAccessiblePlugin) or compile them into the application.
    Likewise, Qt's predefined accessibility support can be built as
    plugin (the default) or directly into the Qt library. The main
    advantage of using plugins is that the accessibility classes are
    only loaded into memory if they are actually used; they don't
    slow down the common case where no assistive technology is being
    used.

    Qt also includes two convenience classes, QAccessibleObject and
    QAccessibleWidget, that inherit from QAccessibleInterface and
    provide the lowest common denominator of metadata (e.g., widget
    geometry, window title, basic help text). You can use them as
    base classes when wrapping your custom QObject or QWidget
    subclasses.

    \sa QAccessibleInterface
*/

/*!
    \enum QAccessible::Action

    This enum describes the possible types of action that can occur.

    \value DefaultAction
    \value Press
    \value SetFocus
    \value Increase
    \value Decrease
    \value Accept
    \value Cancel
    \value Select
    \value ClearSelection
    \value RemoveSelection
    \value ExtendSelection
    \value AddToSelection

    \value FirstStandardAction
    \value LastStandardAction
*/

/*!
    \enum QAccessible::StateFlag

    This enum type defines bit flags that can be combined to indicate
    the state of an accessible object. The values are:

    \value Animated         The object's appearance changes frequently.
    \value Busy             The object cannot accept input at the moment.
    \value Checked          The object's check box is checked.
    \value Collapsed        The object is collapsed, e.g. a closed listview item, or an iconified window.
    \value DefaultButton    The object represents the default button in a dialog.
    \value Expanded         The object is expandable, and currently the children are visible.
    \value ExtSelectable    The object supports extended selection.
    \value Focusable        The object can receive focus. Only objects in the active window can receive focus.
    \value Focused          The object has keyboard focus.
    \value HasPopup         The object opens a popup.
    \value HotTracked       The object's appearance is sensitive to the mouse cursor position.
    \value Invisible        The object is not visible to the user.
    \value Linked           The object is linked to another object, e.g. a hyperlink.
    \value Marqueed         The object displays scrolling contents, e.g. a log view.
    \value Mixed            The state of the object is not determined, e.g. a tri-state check box that is neither checked nor unchecked.
    \value Modal            The object blocks input from other objects.
    \value Movable          The object can be moved.
    \value MultiSelectable  The object supports multiple selected items.
    \value Normal           The normal state.
    \value Offscreen        The object is clipped by the visible area. Objects that are off screen are also invisible.
    \value Pressed          The object is pressed.
    \value Protected        The object is password protected, e.g. a line edit for entering a Password.
    \value ReadOnly         The object can usually be edited, but is explicitly set to read-only.
    \value Selectable       The object is selectable.
    \value Selected         The object is selected.
    \value SelfVoicing      The object describes itself through speech or sound.
    \value Sizeable         The object can be resized, e.g. top-level windows.
    \value Traversed        The object is linked and has been visited.
    \value Unavailable      The object is unavailable to the user, e.g. a disabled widget.
    \omitvalue Moveable

    Implementations of QAccessibleInterface::state() return a combination
    of these flags.
*/

/*!
    \enum QAccessible::Event

    This enum type defines accessible event types.

    \value AcceleratorChanged
    \value Alert
    \value ContextHelpEnd
    \value ContextHelpStart
    \value DefaultActionChanged
    \value DescriptionChanged
    \value DialogEnd
    \value DialogStart
    \value DragDropEnd
    \value DragDropStart
    \value Focus
    \value ForegroundChanged
    \value HelpChanged
    \value LocationChanged
    \value MenuCommand
    \value MenuEnd
    \value MenuStart
    \value NameChanged
    \value ObjectCreated
    \value ObjectDestroyed
    \value ObjectHide
    \value ObjectReorder
    \value ObjectShow
    \value ParentChanged
    \value PopupMenuEnd
    \value PopupMenuStart
    \value ScrollingEnd
    \value ScrollingStart
    \value Selection
    \value SelectionAdd
    \value SelectionRemove
    \value SelectionWithin
    \value SoundPlayed
    \value StateChanged
    \value ValueChanged
*/

/*!
    \enum QAccessible::Role

    This enum defines the role of an accessible object. The roles are:

    \value AlertMessage     An object that is used to alert the user.
    \value Animation        An object that displays an animation.
    \value Application      The application's main window.
    \value Assistant        An object that provids interactive help.
    \value Border           An object that represents a border.
    \value ButtonDropDown   A button that drops down a list of items.
    \value ButtonDropGrid   A button that drops down a grid.
    \value ButtonMenu       A button that drops down a menu.
    \value Canvas           An object that displays graphics that the user can interact with.
    \value Caret            An object that represents the system caret (text cursor).
    \value Cell             A cell in a table.
    \value Chart            An object that displays a graphical representation of data.
    \value CheckBox         An object that represents an option that can be checked or unchecked. Some options provide a "mixed" state, e.g. neither checked nor unchecked.
    \value Client           The client area in a window.
    \value Clock            A clock displaying time.
    \value Column           A column of cells, usually within a table.
    \value ColumnHeader     A header for a column of data.
    \value ComboBox         A list of choices that the user can select from.
    \value Cursor           An object that represents the mouse cursor.
    \value Dial             An object that represents a dial or knob.
    \value Dialog           A dialog box.
    \value Document         A document window, usually in an MDI environment.
    \value EditableText     Editable text
    \value Equation         An object that represents a mathematical equation.
    \value Graphic          A graphic or picture, e.g. an icon.
    \value Grip             A grip that the user can drag to change the size of widgets.
    \value Grouping         An object that represents a logical grouping of other objects.
    \value HelpBalloon      An object that displays help in a separate, short lived window.
    \value HotkeyField      A hotkey field that allows the user to enter a key sequence.
    \value Indicator        An indicator that represents a current value or item.
    \value LayeredPane      An object that can contain layered children, e.g. in a stack.
    \value Link             A link to something else.
    \value List             A list of items, from which the user can select one or more items.
    \value ListItem         An item in a list of items.
    \value MenuBar          A menu bar from which menus are opened by the user.
    \value MenuItem         An item in a menu or menu bar.
    \value NoRole           The object has no role. This usually indicates an invalid object.
    \value PageTab          A page tab that the user can select to switch to a different page in a dialog.
    \value PageTabList      A list of page tabs.
    \value Pane             A generic container.
    \value PopupMenu        A menu which lists options that the user can select to perform an action.
    \value ProgressBar      The object displays the progress of an operation in progress.
    \value PropertyPage     A property page where the user can change options and settings.
    \value PushButton       A button.
    \value RadioButton      An object that represents an option that is mutually exclusive with other options.
    \value Row              A row of cells, usually within a table.
    \value RowHeader        A header for a row of data.
    \value ScrollBar        A scroll bar, which allows the user to scroll the visible area.
    \value Separator        A separator that divides space into logical areas.
    \value Slider           A slider that allows the user to select a value within a given range.
    \value Sound            An object that represents a sound.
    \value SpinBox          A spin box widget that allows the user to enter a value within a given range.
    \value Splitter         A splitter distributing available space between its child widgets.
    \value StaticText       Static text, such as labels for other widgets.
    \value StatusBar        A status bar.
    \value Table            A table representing data in a grid of rows and columns.
    \value TitleBar         The title bar caption of a window.
    \value ToolBar          A tool bar, which groups widgets that the user accesses frequently.
    \value ToolTip          A tool tip which provides information about other objects.
    \value Tree             A list of items in a tree structure.
    \value TreeItem         An item in a tree structure.
    \value UserRole         The first value to be used for user defined roles.
    \value Whitespace       Blank space between other objects.
    \value Window           A top level window.
*/

/*!
    \enum QAccessible::RelationFlag

    This enum type defines bit flags that can be combined to indicate
    the relationship between two accessible objects.

    \value Unrelated        The objects are unrelated.
    \value Self             The objects are the same.
    \value Ancestor         The first object is a parent of the second object.
    \value Child            The first object is a direct child of the second object.
    \value Descendent       The first object is an indirect child of the second object.
    \value Sibling          The objects are siblings.

    \value Up               The first object is above the second object.
    \value Down             The first object is below the second object.
    \value Left             The first object is left of the second object.
    \value Right            The first object is right of the second object.
    \value Covers           The first object covers the second object.
    \value Covered          The first object is covered by the second object.

    \value FocusChild       The first object is the second object's focus child.
    \value Label            The first object is the label of the second object.
    \value Labelled         The first object is labelled by the second object.
    \value Controller       The first object controls the second object.
    \value Controlled       The first object is controlled by the second object.

    \omitvalue HierarchyMask
    \omitvalue GeometryMask
    \omitvalue LogicalMask

    Implementations of relationTo() return a combination of these flags.
    Some values are mutually exclusive.

    Implementations of navigate() can accept only one distinct value.
*/

/*!
    \enum QAccessible::Text

    This enum specifies string information that an accessible object
    returns.

    \value Name         The name of the object.
    \value Description  A short text describing the object.
    \value Value        The value of the object.
    \value Help         A longer text giving information about how to use the object.
    \value Accelerator  The keyboard shortcut that executes the object's default action.