Reading PDF Files Through MSAA¶

Microsoft Active Accessibility defines the IAccessible interface to applications. This interface consists of a set of methods and properties that are defined in the MSAA documentation.

Acrobat implements and exports a set of IAccessible objects of different types to represent a document, its pages, and other elements of the document hierarchy.

An MSAA client can retrieve an IAccessible object for a user interface element in the following four ways:

Set a WinEvent hook, receive a notification, and call AccessibleObjectFromEvent to retrieve an IAccessible interface pointer for the user interface element that generated the event. See Handling event notifications for details.
Call AccessibleObjectFromWindow and pass the user interface element’s window handle. Each open document in Acrobat is associated with its own window handle.
Call AccessibleObjectFromPoint and pass a screen location that lies within the user interface element’s bounding rectangle.
Call an IAccessible method such as accNavigate or get_accParent to move to a different IAccessible object.

Acrobat implementation of IAccessible objects¶

Each type of IAccessible object has a different implementation of the standard methods:

Links, tables, and form fields are explicitly identified through MSAA.
Headers, paragraphs, and other elements of document structure are only represented implicitly.

Note

These elements are explicit in the DOM interface; see Reading PDF Files Through the DOM Interface.

For each document, Acrobat builds a tree of IAccessible objects representing the document and its internal structure. Because there is just one window handle associated with the document, Acrobat posts all event notifications to that window. In each notification, a childID identifies an IAccessible object for an element in the document. For example, when the user tabs to the next link, the EVENT_OBJECT_FOCUS notification includes a childID that is the UID of the link object. See Handling event notifications.

The following interfaces are exported from the IAccessible object by Acrobat:

IGetPDDomNode interface¶

This interface exports one function, get_PDDomNode , which returns a DOM object. The methods described in Reading PDF Files Through the DOM Interface” can then be used on this object.

get_PDDomNode¶

Returns a DOM object. For more information, see Reading PDF Files Through the DOM Interface.

varID is the same as for the other MSAA methods (see Descriptive properties and methods)

HRESULT get_PDDomNode(
VARIANT varID,
IPDDomNode **ppDispDoc);

ISelectText interface¶

In Acrobat 7.0, the ISelectText interface is an interface exported by the IAccessible objects. It exports one function, selectText , that sets the text selection, but specifies the end location via IAccessible objects instead of DOM nodes. The ISelectText interface is available from the root IAccessible object.

selectText¶

Sets the text selection. startAccID and endAccID are the accID identifiers for the starting and ending IAccessible elements, and startIndex and endIndex are zero-based indexes into the text of those IAccessible objects.

LRESULT selectText(
long startAccID,
long startIndex,
long endAccID,
long endIndex);

Identifying IAccessible objects in a document¶

You can identify the type of an IAccessible object by using the get_accRole method to get its Role attribute. However, you must also distinguish individual objects from others of the same type. You can do this by means of a unique identifier (UID) defined by Acrobat.

The IAccessible objects defined by Acrobat export a private interface, IAccID , defined in the file IAccID.h. It contains one function, get_accID. Use this UID to determine when two IAccessible objects refer to the same element in the document.

When a value-change notification or a focus notification has a non-zero childID , the value of childID is the UID of one of the objects on the page or document. Use the UID to uniquely identify the object that is the target of the notification.

get_accID¶

Returns an identifier that is unique within the open document or page.

HRESULT get_accID(long *id);

Parameters

id	(Filled by the method) Returns the unique identifier of the `IAccessible` object. Must not be `NULL`.

Returns

Always returns s_ok.

Example

IAccID *pID;
 long uid;
 /* query for the IAccID interface */
 RESULT hr = pObj->QueryInterface (IID_IAccID,
                                         reinterpret_cast<void **>(&pID));
 if (!FAILED(hr))
 {
         pID->get_accID(&uid);
         pID->Release();
 }

Note

If you obtained the IAccessible object via a call to AccessibleObjectFrom XXX, it is not possible to query directly for this private interface. In that case, you must use this alternate code:

IServiceProvider *sp = NULL;
 hr = n->QueryInterface(IID_IServiceProvider, (LPVOID*)&sp);
 if (SUCCEEDED(hr) && sp) {
         hr = sp->QueryService(SID_AccID, IID_IAccID, (LPVOID*)&pID);
         sp->Release();
 }

IAccessible method summary¶

This section provides a brief syntax summary of the IAccessible interface methods as defined by MSAA. All methods return HRESULT. The methods and properties are organized into the following groups:

Navigation and hierarchy¶

This section provides information on the APIs used in navigation and to traverse the hierarchy.

accNavigate¶

Traverses to another user interface element within a container and retrieves the object. All visual objects support this method.

accNavigate (long navDir, VARIANT varStart, VARIANT* pvarEnd);

Properties

navDir: [in]

The direction to navigate, in spatial order or logical order. These are the spatial navigation constants:

NAVDIR_UP
NAVDIR_DOWN NAVDIR_RIGHT NAVDIR_LEFT

These are the logical navigation constants:

NAVDIR_FIRSTCHILD
NAVDIR_LASTCHILD NAVDIR_NEXT NAVDIR_PREVIOUS

All accNavigate methods in PDF objects support the logical navigation directions. Only a few (PDF Structure Element, PDF ComboBox Form Field, and PDF ListBox Form Field) support the spatial navigation directions. Spatial navigation is only supported where it is explicitly noted.

varStart

[in]

CHILDID_SELF to start navigation at the object itself, a child ID to start at one of the object’s child elements.

pvarEnd

[out, retval]

Returns a structure that contains information about the destination object. See MSAA documentation for details.

Returns

HRESULT

get_accChild¶

Retrieves an IDispatch interface pointer for the specified child, if one exists. All objects support this property.

get_accChild (VARIANT varChildID, IDispatch** ppdispChild);

Properties

varChildID: [in]

The child ID for which to obtain a pointer. This can be a UID or the 1-based index of the child to retrieve.

ppdispChild

[out, retval]

Returns the address of the child’s IDispatch interface.

Returns

HRESULT

get_accChildCount¶

Retrieves the number of children that belong to this object. All objects support this property.

get_accChildCount (long* pcountChildren);

Properties

pcountChildren

[out, retval]

Returns the number of children. The children are accessible objects or child elements. If the object has no children, this value is zero.

Returns

HRESULT

get_accParent¶

Retrieves an IDispatch interface pointer for the parent of this object. All objects support this property.

get_accParent (IDispatch** ppdispParent);

Properties

ppdispParent

[out, retval]

Returns the address of the parent’s IDispatch interface.

Returns

HRESULT

Descriptive properties and methods¶

This section provides information on the descriptive APIs.

accDoDefaultAction¶

Performs the object’s default action. Not all objects have a default action.

accDoDefaultAction (VARIANT varID);

Properties

varID: [in]

CHILDID_SELF to perform the action for the object itself, a child ID to perform the action for one of the object’s child elements.

Returns

HRESULT

get_accDefaultAction¶

Retrieves a string that describes the object’s default action. Not all objects have a default action.

get_accDefaultAction(VARIANT varID, BSTR* pszDefaultAction);

Properties

varID: [in]

CHILDID_SELF to get information for the object itself, a child ID to get information for one of the object’s child elements.

pszDefaultAction

[out, retval]

Returns a localized string that describes the default action for the object, or NULL if this object has no default action.

Returns

HRESULT

get_accDescription¶

Retrieves a string that describes the visual appearance of the object. Not all objects have a description.

get_accDescription (VARIANT varID, BSTR* pszDescription);

Properties

varID: [in]

CHILDID_SELF to get information for the object itself, a child ID to get information for one of the object’s child elements.

pszDescription

[out, retval]

Returns a localized string that describes the object, or NULL if this object has no description.

Returns

HRESULT

get_accName¶

Retrieves the name of the object. All objects have a name.

get_accName (VARIANT varID, BSTR* pszName );

Properties

varID: [in]

CHILDID_SELF to get information for the object itself, a child ID to get information for one of the object’s child elements.

pszName

[out, retval]

Returns a localized string that contains the name of the object.

Returns

HRESULT

get_accRole¶

Retrieves the role of the object. All objects have a role.

get_accRole (VARIANT varID, VARIANT* pvarRole );

Properties

varID: [in]

CHILDID_SELF to get information for the object itself, a child ID to get information for one of the object’s child elements.

pvarRole

[out, retval]

Returns a structure that contain an object role constant in its IVal member.

Returns

HRESULT

get_accState¶

Retrieves the state of the object. All objects have a state.

get_accState (VARIANT varID, VARIANT* pvarState );

Properties

varID: [in]

CHILDID_SELF to get information for the object itself, a child ID to get information for one of the object’s child elements.

pvarRole

[out, retval]

Returns a structure that contain an object state constant in its IVal member.

Returns

HRESULT

get_accValue¶

Retrieves the value of the object. Not all objects have a value.

get_accValue (VARIANT varID, BSTR* pszValue );

Properties

varID: [in]

CHILDID_SELF to get information for the object itself, a child ID to get information for one of the object’s child elements.

pszValue

[out, retval]

Returns a localized string that contains the current value of the object.

Returns

HRESULT

Selection and focus¶

This section provides information on the selection and focus APIs.

accSelect¶

Modifies the selection or moves the keyboard focus of the object. All objects that support selection or receive the keyboard focus support this method.

accSelect (long flagsSelect, VARIANT varID);

Properties

flagsSelect: [in]

Flags that control how the selection or focus operation is performed. A logical OR of these SELFLAG constants:

SELFLAG_NONE
SELFLAG_TAKEFOCUS SELFLAG_TAKESELECTION SELFLAG_EXTENDSELECTION SELFLAG_ADDSELECTION SELFLAG_REMOVESELECTION

varID: [in]

CHILDID_SELF to select the object itself, a child ID to select one of the object’s child elements.

Returns

HRESULT

get_accFocus¶

Retrieves the object that has the keyboard focus. All objects that receive the keyboard focus support this property.

get_accFocus (VARIANT* pvarID);

Properties

pvarID

[out, retval]

Returns the address of a VARIANT structure that contains information about the object that has the focus. See MSAA documentation for details.

Returns

HRESULT

get_accSelection¶

Retrieves the selected children of the object. All objects that support selection support this property.

get_accSelection (VARIANT* pvarChildren);

Properties

pvarChildren

[out, retval]

Returns the address of a VARIANT structure that contains information about the selected children. See the MSAA documentation for details.

Returns

HRESULT

Spatial mapping¶

accLocation¶

Retrieves the object’s current screen location. All visual objects support this method.

accLocation (long* pxLeft, long* pyTop, long* pcxWidth, long* pcyHeight, VARIANT varID );

Properties

pxLeft, pxTop [out]	Return the x and y screen coordinates of the upper-left boundary of the object’s location. (The origin is the upper left corner of the screen.)
pxWidth, pxHeight [in]	Return the object’s width and height in pixels.
varID [in]	`CHILDID_SELF` to get information for the object itself, a child ID to get information for one of the object’s child elements.

Returns

HRESULT

accHitTest¶

Retrieves the object at a specific screen location. All visual objects support this method.

accHitTest (long, long, VARIANT* pvarID);

Properties

pxLeft, pxTop [in]

The x and y screen coordinates of the point to test. (The origin is the upper left corner of the screen.)

pvarID: [out, retval]

Address of a VARIANT structure that identifies the object at the specified point. The information returned depends on the location of the specified point in relation to the object whose accHitTest method is being called. You can use this method to determine whether the object at that point is a child of the object for which the method is called. For details, see the MSAA documentation.

For PDF objects, hit testing has been implemented in a very basic way; it does not identify the boundaries of the object itself with fine granularity, but reports whether or not the tested location is within the bounding box of an element or subtree.

Returns

HRESULT

IAccessible object types for PDF¶

This section describes the MSAA IAccessible object types that are defined to represent PDF documents and their elements. For each object, its methods are listed along with notes on how the implementation is specific to the object type.

Note

Methods that are not listed are not implemented for a given object type.

The objects are:

The following are some general notes:

PDF form fields generally correspond closely to standard user interface elements described in the MSAA SDK document. The IAccessible objects of form fields attempt to match the behavior described in Appendix A, “Supported User Interface Elements,” of the MSAA document. An exception is the PDF combo box, which has a much simpler structure.
Form fields, links, and comments, as well as the document as a whole, can take keyboard focus. Subparts of the document (sections, paragraphs, and so on) cannot take focus.
A document’s contents may be only partially visible on the screen. The get_accLocation method for a given object returns the screen location of the visible part of the object only. You can use this method to determine which portions of the content are visible.

PDF Document¶

Represents the contents of an entire PDF document. The subtree of IAccessible objects beneath the PDF Document object reflects the logical structure of the document.

Note

Content that is not part of the logical structure, such as page headers and footers, is not presented through the MSAA interface.

Method	Implementation notes
accHitTest	Returns the object at a given location if the location is within the document’s bounding box.
accLocation	Returns the screen coordinates of the visible part of the document.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	For `SELFLAG_TAKEFOCUS` , the focus is set to the window containing the document and the document is positioned at the beginning. The other `SELFLAG` values are not supported.
get_accChild	Returns a child object.
get_accChildCount	Returns the number of child objects beneath this one.
get_accDescription	The description contains the full path name of the document and the number of pages it contains: “fileName, XXX pages”.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accParent	The parent is `NULL`.
get_accRole	The role is `ROLE_SYSTEM_DOCUMENT`.
get_accSelection	Returns `NULL`.
get_accState	The state is `STATE_SYSTEM_READONLY`.
get_accValue	If the root of the structure tree has an `Alt` attribute, the value is the contents of the `Alt` attribute.

PDF Page¶

Represents the contents of one page of a PDF document. The subtree of IAccessible objects beneath the PDF Page node reflects the logical structure of the page.

Note

Content that is not part of the logical structure, such as page headers and footers, is not presented through the MSAA interface.

Method	Implementation notes
accHitTest	Returns the object at the given location if the location is within the page’s bounding box.
accLocation	Returns the screen coordinates of the visible part of the page.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	For `SELFLAG_TAKEFOCUS` , the focus is set to the window containing the page and the page is positioned at the top. The other `SELFLAG` values are not supported.
get_accChild	Returns a child object.
get_accChildCount	Returns the number of child objects beneath this one.
get_accDescription	The description contains the full path name of the document and the page number of the page: “fileName, page XXX”.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accParent	The parent is `NULL`.
get_accRole	A custom role, `Page` , is defined for this object.
get_accSelection	Returns `NULL`.
get_accState	The state is `STATE_SYSTEM_READONLY`.
get_accValue	If the root of the structure tree has an `Alt` attribute, the value is the contents of the `Alt` attribute

PDF Protected Document¶

Represents a protected document. When the permissions associated with a document disable accessibility, the contents are not exported through the MSAA interface. The IAccessible object for such a document informs the client that the document is protected.

Method	Implementation notes
accHitTest	Returns `NULL`.
accLocation	The screen coordinates of the visible part of the document.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	Returns `NULL`.
get_accChildCount	The child count is 0.
get_accFocus	Returns `NULL`.
get_accName	The name is “Alert: Protection Failure”.
get_accParent	The parent is `NULL`.
get_accRole	The role is `ROLE_SYSTEM_TEXT`.
get_accSelection	Returns `NULL`.
get_accState	The state is `STATE_SYSTEM_ALERT_MEDIUM + STATE_SYSTEM_UNAVAILABLE + STATE_SYSTEM_READONLY`.
get_accValue	The value is “This document’s security settings prevent access.”

Empty PDF Document¶

Represents an empty or apparently empty document. A PDF file may have no contents to export through MSAA if, for instance, the file is a scanned image that has not been run through an optical character recognition (OCR) tool. The IAccessible object for empty documents and pages informs the client that there may be a problem, even if the document or page is genuinely empty.

Method	Implementation notes
accHitTest	Returns `NULL`.
accLocation	Returns the screen coordinates of the visible part of the document.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	Returns `NULL`.
get_accChildCount	The child count is 0.
get_accFocus	Returns `NULL`.
get_accName	The name is “Alert: Empty document”.
get_accParent	The parent is `NULL`.
get_accRole	The role is `ROLE_SYSTEM_TEXT`.
get_accSelection	Returns `NULL`.
get_accState	The state is `STATE_SYSTEM_READONLY`.
get_accValue	The value is “This document appears to be empty. It may be a scanned image that needs OCR or it may have malformed structure.”

PDF Structure Element¶

Represents a subtree of the logical structure tree for the document. It might correspond to a paragraph, a heading, a chapter, a span of text within a word, or a figure.

Method	Implementation notes
accDoDefaultAction	If the element has state `STATE_SYSTEM_LINKED` , performs the action associated with the link.
accHitTest	Returns this object or any child at the given location if the location is within the bounding box of this object.
accLocation	Returns the screen coordinates of the visible part of the subtree.
accNavigate	Only spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ) is supported for table elements (`ROLE_SYSTEM_CELL` , `ROLE_SYSTEM_ROW` , `ROLE_SYSTEM_ROWHEADER` , `ROW_SYSTEM_COLUMNHEADER` ).
accSelect	For `SELFLAG_TAKEFOCUS` , sets focus to the document window and positions the document to the beginning of the structure element content. The other `SELFLAG` values are not supported.
get_accChild	Returns a child object.
get_accChildCount	Returns the number of child objects beneath this one. If the node has an `Alt` or `ActualText` attribute, the child count is always zero.
get_accDefaultAction	If the element has state `STATE_SYSTEM_LINKED` , returns a text description of the action associated with the link (such as “go to page 5” or “play movie”).
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accParent	The parent is either another structure element or the document structure root.
get_accRole	The role is one of: ROLE_SYSTEM_GROUPING ROLE_SYSTEM_TABLE ROLE_SYSTEM_CELL ROLE_SYSTEM_ROW ROLE_SYSTEM_ROWHEADER ROW_SYSTEM_COLUMNHEADER
get_accSelection	Returns `NULL`.
get_accState	The state is a logical OR of one or more of the following: STATE_SYSTEM_READONLY STATE_SYSTEM_LINKED STATE_SYSTEM_FOCUSABLE STATE_SYSTEM_FOCUSED `STATE_SYSTEM_READONLY` is always set. If the element is part of a link (that is, if it has an ancestor of role `ROLE_SYSTEM_LINK` ) then both `STATE_SYSTEM_LINKED` and `STATE_SYSTEM_FOCUSABLE` are set, and `STATE_SYSTEM_FOCUSED` can also be set.
get_accValue	If this node has an `Alt` or `ActualText` attribute, the value is the contents of the attribute.

PDF Content Element¶

Corresponds to a leaf node of the logical structure tree for the document. It corresponds to marking commands in the page content stream.

Method	Implementation notes
accDoDefaultAction	If the element has state `STATE_SYSTEM_LINKED` , performs the action associated with the link.
accHitTest	Returns this object if the given location is within the bounding box of this object.
accLocation	Returns the screen coordinates of the visible part of the element.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	For `SELFLAG_TAKEFOCUS` , sets focus to the document window and positions the document to the beginning of the content. The other `SELFLAG` values are not supported.
get_accChildCount	The child count is 0.
get_accDefaultAction	If the element has state `STATE_SYSTEM_LINKED` , describes the action associated with the link.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accParent	The parent is either a structure element or the document structure root.
get_accRole	The role is one of: ROLE_SYSTEM_TEXT ROLE_SYSTEM_GRAPHIC ROLE_SYSTEM_CLIENT
get_accSelection	Returns `NULL`.
get_accState	The state is a logical OR of one or more of the following: STATE_SYSTEM_READONLY STATE_SYSTEM_LINKED STATE_SYSTEM_FOCUSABLE STATE_SYSTEM_FOCUSED `STATE_SYSTEM_READONLY` is always set. If the element is part of a link (that is, if it has an ancestor of role `ROLE_SYSTEM_LINK` ) then both `STATE_SYSTEM_LINKED` and `STATE_SYSTEM_FOCUSABLE` are set, and `STATE_SYSTEM_FOCUSED` can also be set.
get_accValue	If this node has an `Alt` or `ActualText` attribute, the value is the content of that attribute. Otherwise, the value is all of the text contained in the marking commands for this node.

PDF Comment¶

Corresponds to a comment, such as a text note or highlight comment, attached to the document.

Note

PDF comments cover a range of objects, many of which do not map into the standard MSAA roles. The IAccessible object captures the most important properties of comments.

Method	Implementation notes
accDoDefaultAction	The default action depends on the type of comment. It can, for example, open or close a popup.
accHitTest	Returns this object if the given location is within the bounding box of this object.
accLocation	Returns the screen coordinates of the visible part of the object.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	Supports `SELFLAG_TAKEFOCUS` (that is, selecting the comment gives it the keyboard focus).
get_accChildCount	The child count is 0.
get_accDefaultAction	Describes the default action, which depends on the type of comment.
get_accDescription	For file attachment and sound comments, a description of the icon for the comment.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accName	The name indicates the type of comment; for example, Text Comment or Underline Comment. If the comment is open and has a title, the name also contains the title of the comment. If the comment is a Free Text comment or modifies a span of text (such as an Underline or Strikeout Comment), the name also contains the text.
get_accParent	The parent is either a structure element or the document structure root.
get_accRole	The role is one of: ROLE_SYSTEM_TEXT ROLE_SYSTEM_WHITESPACE ROLE_SYSTEM_PUSHBUTTON
get_accSelection	Returns `NULL`.
get_accState	The state is a logical OR of one or more of the following: STATE_SYSTEM_READONLY STATE_SYSTEM_INVISIBLE STATE_SYSTEM_LINKED STATE_SYSTEM_FOCUSABLE STATE_SYSTEM_EXPANDED STATE_SYSTEM_COLLAPSED STATE_SYSTEM_FOCUSED If a comment can be opened, `STATE_SYSTEM_LINKED` is set. `STATE_SYSTEM_EXPANDED` and `STATE_SYSTEM_COLLAPSED` indicate whether the comment is open.
get_accValue	If the comment is open, the value is the contents of the comment pop-up window. If the comment is a type that does not open, the value is the contents of the comment itself.

PDF Link¶

Corresponds to a link in the document.

Method	Implementation notes
accDoDefaultAction	Performs the link’s action.
accHitTest	Returns this object or any child at the given location if the location is within the bounding box of this object.
accLocation	Returns the screen coordinates of the visible part of the object.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	Supports `SELFLAG_TAKEFOCUS`
get_accChild	Returns a child object.
get_accChildCount	Returns the number of children. If the node has an `Alt` or `ActualText` attribute, the child count is always zero.
get_accDefaultAction	Describes the action defined for this link.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accName	If there is an `Alt` or `ActualText` attribute associated with this link, the name is the associated `Alt` text or `ActualText`. Otherwise, the name is the value of the first content child.
get_accParent	The parent is either a structure element or the document structure root.
get_accRole	The role is `ROLE_SYSTEM_LINK`.
get_accSelection	Returns `NULL`.
get_accState	The state is a logical OR of the following: STATE_SYSTEM_READONLY STATE_SYSTEM_INVISIBLE STATE_SYSTEM_LINKED STATE_SYSTEM_FOCUSABLE STATE_SYSTEM_FOCUSED
get_accValue	The value is a unique identifier for each link.

PDF Text Form Field¶

Corresponds to a text form field in the document.

Method	Implementation notes
accDoDefaultAction	Sets focus to the text field for editing.
accHitTest	Returns this object if the given location is within the bounding box of this object.
accLocation	Returns the screen coordinates of the visible part of the object.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	Supports `SELFLAG_TAKEFOCUS` (that is, selecting the field gives it the keyboard focus).
get_accChildCount	The child count is 0.
get_accDefaultAction	The default action is “DoubleClick”, which sets the keyboard focus to this field.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accName	The user name (short description) of the form field.
get_accParent	Returns the parent object.
get_accRole	The role is `ROLE_SYSTEM_TEXT`.
get_accState	The state of the text field is a logical OR of one of more of: STATE_SYSTEM_INVISIBLE STATE_SYSTEM_UNAVAILABLE STATE_SYSTEM_READONLY STATE_SYSTEM_SELECTABLE STATE_SYSTEM_FOCUSABLE STATE_SYSTEM_FOCUSED STATE_SYSTEM_PROTECTED
get_accValue	The value is the text in the text field.

PDF Button Form Field¶

Corresponds to a button form field in the document.

Method	Implementation notes
accDoDefaultAction	Presses the button.
accHitTest	Returns this object if the given location is within the bounding box of this object.
accLocation	Returns the screen coordinates of the visible part of the object.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	Supports `SELFLAG_TAKEFOCUS` (that is, selecting the field gives it the keyboard focus).
get_accChildCount	The child count is 0.
get_accDefaultAction	The default action is “Press”.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accName	The user name of the form field (short description).
get_accParent	Returns the parent object.
get_accRole	The role is `ROLE_SYSTEM_PUSHBUTTON`.
get_accState	The state of the button is a logical OR of one or more of: STATE_SYSTEM_INVISIBLE STATE_SYSTEM_UNAVAILABLE STATE_SYSTEM_READONLY STATE_SYSTEM_FOCUSABLE STATE_SYSTEM_FOCUSED

PDF CheckBox Form Field¶

Corresponds to a checkbox form field in the document.

Method	Implementation notes
accDoDefaultAction	Checks or unchecks the box.
accHitTest	Returns this object if the given location is within the bounding box of this object.
accLocation	Returns the screen coordinates of the visible part of the object.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	Supports `SELFLAG_TAKEFOCUS` (that is, selecting the field gives it the keyboard focus).
get_accChildCount	The child count is 0.
get_accDefaultAction	If the check box has been selected, the default action is “UnCheck”. If the check box has not been selected, the default action is “Check”.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accName	The user name (short description) of the form field.
get_accParent	Returns the parent object.
get_accRole	The role is `ROLE_SYSTEM_CHECKBUTTON`.
get_accState	The state of the check box is a logical OR of one or more of: STATE_SYSTEM_INVISIBLE STATE_SYSTEM_UNAVAILABLE STATE_SYSTEM_READONLY STATE_SYSTEM_FOCUSABLE STATE_SYSTEM_FOCUSED STATE_SYSTEM_CHECKED

PDF RadioButton Form Field¶

Corresponds to a radio button form field in the document.

Method	Implementation notes
accDoDefaultAction	Clicks the radio button.
accHitTest	Returns this object if the given location is within the bounding box of this object.
accLocation	Returns the screen coordinates of the visible part of the object.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	Supports `SELFLAG_TAKEFOCUS` (that is, selecting the field gives it the keyboard focus).
get_accChildCount	The child count is 0.
get_accDefaultAction	The default action is “Check”.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accName	The user name (short description) of the form field.
get_accParent	Returns the parent object.
get_accRole	The role is `ROLE_SYSTEM_RADIOBUTTON`.
get_accState	The state of the radio button is a logical OR of one or more of: STATE_SYSTEM_INVISIBLE STATE_SYSTEM_UNAVAILABLE STATE_SYSTEM_READONLY STATE_SYSTEM_FOCUSABLE STATE_SYSTEM_FOCUSED STATE_SYSTEM_CHECKED

PDF ComboBox Form Field¶

Corresponds to a combo box form field in the document. It can represent either the combo box itself, or a list item in a combo box.

Method	Implementation notes
accDoDefaultAction	The combo box does not have a default action. For a list item, the default action is “DoubleClick”, which selects the list item.
accHitTest	For a combo box, returns this object or any child at the given location if the location is within the bounding box of this object. For a list item, returns this object if the given location is within the bounding box of this object.
accLocation	For a combo box, returns the screen coordinates of the visible part of the object. For a list item, the location is always reported as 0,0,0,0.
accNavigate	Spatial directions `NAVDIR_UP` and `NAVDIR_DOWN` are available for list items.
accSelect	The combo box supports `SELFLAG_TAKEFOCUS` (that is, selecting the field gives it the keyboard focus). For a list item, sets the combo box to the list item value.
get_accChild	For a combo box, gets the child items. A list item has no children.
get_accChildCount	For a combo box, the child count is the number of items in the list. For a list item, the child count is 0.
get_accDefaultAction	The combobox does not have a default action. For a list item, the default action is “DoubleClick”, which selects the list item.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accName	For a combo box, the name is the user name (short description) of the form field if it has been defined. For a list item, the name is the text of the list item.
get_accParent	Returns the parent object.
get_accSelection	Returns `NULL`.
get_accRole	For a combo box, the role is `ROLE_SYSTEM_COMBOBOX`. For a list item, the role is `ROLE_SYSTEM_LISTITEM`.
get_accState	For a combo box, the state is a logical OR of one or more these values: STATE_SYSTEM_INVISIBLE STATE_SYSTEM_UNAVAILABLE STATE_SYSTEM_READONLY STATE_SYSTEM_FOCUSABLE STATE_SYSTEM_FOCUSED STATE_SYSTEM_SELECTABLE STATE_SYSTEM_SELECTED For a list box item, the state is a logical OR of one or more these values: STATE_SYSTEM_READONLY STATE_SYSTEM_SELECTABLE STATE_SYSTEM_SELECTED STATE_SYSTEM_INVISIBLE STATE_SYSTEM_UNAVAILABLE
get_accValue	For a combo box, the value is the text value of the currently selected list item. For a list item, the value is the text of the list item.

PDF List Box Form Field¶

Corresponds to a list box form field in the document. It can represent either the list box itself or a list item in a list box.

Method	Implementation notes
accDoDefaultAction	The list box does not have a default action. For a list item, the default action is “Double Click,” which selects the item.
accHitTest	For a list box, returns this object or any child at the given location if the location is within the bounding box of this object. For a list item, returns this object if the given location is within the bounding box of this object.
accLocation	For a list box, returns the screen coordinates of the visible part of the object. For a list item, the location is always reported as 0,0,0,0.
accNavigate	Spatial directions `NAVDIR_UP` and `NAVDIR_DOWN` are available for list items.
accSelect	The list box supports `SELFLAG_TAKEFOCUS` (that is, selecting the field gives it the keyboard focus). For a list item, sets the list box selection to the list item value.
get_accChild	For a list box, gets the child items. A list item has no children.
get_accChildCount	For a list box, the child count is the number of items in the list box. For a list item, the child count is 0.
get_accDefaultAction	The list box does not have a default action. For a list item, the default action is “Double Click,” which selects the item.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accName	For a list box, the name is the user name (short description) for the form field. For a list item, the name is the text of the list item.
get_accParent	Returns the parent object.
get_accRole	For a list box, the role is `ROLE_SYSTEM_LIST`. For a list item, the role is `ROLE_SYSTEM_LISTITEM`.
get_accState	For a list box, the state is a logical OR of one or more these values: STATE_SYSTEM_INVISIBLEc STATE_SYSTEM_UNAVAILABLE STATE_SYSTEM_READONLY STATE_SYSTEM_FOCUSABLE For a list item, the state is a logical OR of one or more these values: STATE_SYSTEM_READONLY STATE_SYSTEM_SELECTABLE STATE_SYSTEM_SELECTED STATE_SYSTEM_INVISIBLE STATE_SYSTEM_UNAVAILABLE
get_accSelection	Returns `NULL`.
get_accValue	For a list box, the value is the text value of the currently selected list item. For a list item, the `Value` attribute is the text of the list item.

PDF Digital Signature Form Field¶

Corresponds to a digital signature form field in the document.

Method	Implementation notes
accDoDefaultAction	Signs the document if the signature field is unsigned and has either been opened with Acrobat or the document has permissions that allow signing. If the document is signed, the default action brings up a dialog box containing the signature information.
accHitTest	Returns this object if the given location is within the bounding box of this object.
accLocation	Returns the screen coordinates of the visible part of the object.
accNavigate	Does not support spatial navigation (`NAVDIR_UP` , `NAVDIR_DOWN` , `NAVDIR_RIGHT` , `NAVDIR_LEFT` ).
accSelect	Supports `SELFLAG_TAKEFOCUS`.
get_accChildCount	The child count is 0.
get_accDefaultAction	Returns `NULL`.
get_accFocus	Returns the object that has the keyboard focus if it is this object or its child.
get_accName	The user name (short description) of the form field.
get_accParent	Returns the parent object.
get_accRole	The Digital Signature form field does not map to any of the existing roles, and a custom role, `Signature` , has been defined for it.
get_accState	The `State` attribute of the digital signature is a logical OR of one of more of these values: STATE_SYSTEM_INVISIBLE STATE_SYSTEM_UNAVAILABLE STATE_SYSTEM_READONLY STATE_SYSTEM_FOCUSABLE STATE_SYSTEM_FOCUSED STATE_SYSTEM_CHECKED STATE_SYSTEM_TRAVERSED If `STATE_SYSTEM_CHECKED` is set, but not `STATE_SYSTEM_TRAVERSED` , the signature is unverified. If `STATE_SYSTEM_TRAVERSED` is set, but not `STATE_SYSTEM_CHECKED` , the signature is invalid. If both `STATE_SYSTEM_CHECKED` and `STATE_SYSTEM_TRAVERSED` are set, the signature is valid.
get_accValue	The `Value` attribute is the name and date of the signature, if that information is present.

PDF Caret¶

Represents a caret (text cursor). If a document contains the system caret because focus is within an editable text field or an editable ComboBox field, clients can obtain an IAccessible object for the caret to determine where it is located.

Method	Implementation notes
accHitTest	Returns this object if the given location is within the bounding box of this object.
accLocation	Returns the screen coordinates of the caret, both when the caret is in a form field and when it is in the document.
get_accChildCount	The child count is 0.
get_accDescription	The description is a string containing the index of the character in the field that follows the caret. If the caret is at the beginning of the field, the description string is “0”. If the caret follows the first character, the description string is “1”.
get_accParent	The parent is the field containing the caret. However, the caret `IAccessible` object is not listed among the children of that field’s `IAccessible` object.
get_accRole	The role is `ROLE_SYSTEM_CARET`.
get_accState	The state is 0.
get_accValue	The value is the current value of the Text field or ComboBox form field containing the caret.