This interface gives read-only access to text. More...

import"AccessibleText.idl";

Inheritance diagram for IAccessibleText:

Public Member Functions
HRESULT	addSelection ([in] long startOffset, [in] long endOffset)
	Adds a text selection. More...

HRESULT	removeSelection ([in] long selectionIndex)
	Unselects a range of text. More...

HRESULT	setCaretOffset ([in] long offset)
	Sets the position of the caret. More...

HRESULT	setSelection ([in] long selectionIndex, [in] long startOffset, [in] long endOffset)
	Changes the bounds of an existing selection. More...

HRESULT	scrollSubstringTo ([in] long startIndex, [in] long endIndex, [in] enum IA2ScrollType scrollType)
	Makes a specific part of string visible on screen. More...

HRESULT	scrollSubstringToPoint ([in] long startIndex, [in] long endIndex, [in] enum IA2CoordinateType coordinateType, [in] long x, [in] long y)
	Moves the top left of a substring to a specified location. More...

Properties
BSTR	attributes ([in] long offset, [out] long startOffset, [out] long endOffset) `[get]`
	Returns text attributes. More...

long	caretOffset `[get]`
	Returns the position of the caret. More...

long	characterExtents ([in] long offset, [in] IA2CoordinateType coordType, [out] long x, [out] long y, [out] long width) `[get]`
	Returns the bounding box of the specified position. More...

long	nSelections `[get]`
	Returns the number of active non-contiguous selections. More...

long	offsetAtPoint ([in] long x, [in] long y, [in] IA2CoordinateType coordType) `[get]`
	Returns the text position for the specified screen position. More...

long	selection ([in] long selectionIndex, [out] long startOffset) `[get]`
	Returns the character offsets of Nth active text selection. More...

BSTR	text ([in] long startOffset, [in] long endOffset) `[get]`
	Returns the substring between the two given indices. More...

BSTR	textBeforeOffset ([in] long offset, [in] IA2TextBoundaryType boundaryType, [out] long startOffset, [out] long endOffset) `[get]`
	Returns a text portion before the given position. More...

BSTR	textAfterOffset ([in] long offset, [in] IA2TextBoundaryType boundaryType, [out] long startOffset, [out] long endOffset) `[get]`
	Returns a text portion after the given position. More...

BSTR	textAtOffset ([in] long offset, [in] IA2TextBoundaryType boundaryType, [out] long startOffset, [out] long endOffset) `[get]`
	Returns a text portion that spans the given position. More...

long	nCharacters `[get]`
	Returns total number of characters. More...

IA2TextSegment	newText `[get]`
	Returns any inserted text. More...

IA2TextSegment	oldText `[get]`
	Returns any removed text. More...

Detailed Description

This interface gives read-only access to text.

The IAccessibleText interface should be implemented by all components that present textual information on the display like buttons, text entry fields, or text portions of the document window. The interface provides access to the text's content, attributes, and spatial location. However, text can not be modified with this interface. That is the task of the IAccessibleEditableText interface.

The text length, i.e. the number of characters in the text, is returned by IAccessibleText::nCharacters. All methods that operate on particular characters (e.g. IAccessibleText::textAtOffset) use character indices from 0 to length-1. All methods that operate on character positions (e.g. IAccessibleText::text) use indices from 0 to length.

Please note that accessible text does not necessarily support selection. In this case it should behave as if there where no selection. An empty selection is used for example to express the current cursor position.

Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.

E_FAIL is returned in the following cases

endOffset < startOffset
endoffset > length

Member Function Documentation

◆ addSelection()

HRESULT IAccessibleText::addSelection	(	[in] long	startOffset,
		[in] long	endOffset
	)

Adds a text selection.

Parameters

[in]	startOffset	Starting offset ( 0 based).
[in]	endOffset	Offset of first character after new selection (0 based).

Return values

S_OK
E_INVALIDARG	if bad [in] passed

Note: Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.

Implemented in AccessibleText.

◆ removeSelection()

HRESULT IAccessibleText::removeSelection ( [in] long selectionIndex )

Unselects a range of text.

Parameters

[in] selectionIndex Index of selection to remove (0 based).

Return values

S_OK
E_INVALIDARG	if bad [in] passed

Implemented in AccessibleText.

◆ scrollSubstringTo()

HRESULT IAccessibleText::scrollSubstringTo	(	[in] long	startIndex,
		[in] long	endIndex,
		[in] enum IA2ScrollType	scrollType
	)

Makes a specific part of string visible on screen.

Parameters

[in]	startIndex	0 based character offset.
[in]	endIndex	0 based character offset - the offset of the character just past the last character of the string.
[in]	scrollType	Defines where the object should be placed on the screen.

Return values

S_OK
E_INVALIDARG	if bad [in] passed

Note: Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.

Implemented in AccessibleText.

◆ scrollSubstringToPoint()

HRESULT IAccessibleText::scrollSubstringToPoint	(	[in] long	startIndex,
		[in] long	endIndex,
		[in] enum IA2CoordinateType	coordinateType,
		[in] long	x,
		[in] long	y
	)

Moves the top left of a substring to a specified location.

Parameters

[in]	startIndex	0 based character offset.
[in]	endIndex	0 based character offset - the offset of the character just past the last character of the string.
[in]	coordinateType	Specifies whether the coordinates are relative to the screen or the parent object.
[in]	x	Defines the x coordinate.
[in]	y	Defines the y coordinate.

Return values

S_OK
S_FALSE	if the object is already at the specified location.
E_INVALIDARG	if bad [in] passed

Note: Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.

Implemented in AccessibleText.

◆ setCaretOffset()

HRESULT IAccessibleText::setCaretOffset ( [in] long offset )

Sets the position of the caret.

The caret position/offset is that of the character logically following it, e.g. to the right of it in a left to right language.

Setting the caret position may or may not alter the current selection. A change of the selection is notified to the accessibility event listeners with an ::IA2_EVENT_TEXT_SELECTION_CHANGED event.

When the new caret position differs from the old one (which, of course, is the standard case) this is notified to the accessibility event listeners with an ::IA2_EVENT_TEXT_CARET_MOVED event.

Parameters

[in] offset The new index of the caret. This caret is actually placed to the left side of the character with that index. An index of 0 places the caret so that the next insertion goes before the first character. An index of IAccessibleText::nCharacters leads to insertion after the last character. Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.

Return values

S_OK
E_FAIL	if the caret cannot be set
E_INVALIDARG	if bad [in] passed

Implemented in AccessibleText.

◆ setSelection()

HRESULT IAccessibleText::setSelection	(	[in] long	selectionIndex,
		[in] long	startOffset,
		[in] long	endOffset
	)

Changes the bounds of an existing selection.

Parameters

[in]	selectionIndex	Index of selection to change (0 based)
[in]	startOffset	New starting offset (0 based)
[in]	endOffset	New ending offset (0 based) - the offset of the character just past the last character of the selection.

Return values

S_OK
E_INVALIDARG	if bad [in] passed

Note: Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.

Implemented in AccessibleText.

Property Documentation

◆ attributes

BSTR IAccessibleText::attributes([in] long offset, [out] long startOffset, [out] long endOffset)

get

Returns text attributes.

Parameters

[in]	offset	Text offset (0 based). Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.
[out]	startOffset	The starting offset of the character range over which all text attributes match those of offset. (0 based)
[out]	endOffset	The offset of the first character past the character range over which all text attributes match those of offset. (0 based)
[out]	textAttributes	A string of attributes describing the text. The attributes are described in the text attributes specification on the IAccessible2 web site.

Return values

S_OK
S_FALSE	if there is nothing to return, [out] values are 0s and NULL respectively
E_INVALIDARG	if bad [in] passed

◆ caretOffset

long IAccessibleText::caretOffset

get

Returns the position of the caret.

Returns the 0-based offset of the caret within the text. If the text is implemented as a tree of text objects with embed characters in higher levels representing substrings of child text objects and the caret is in one of the child text objects, then the offset in the higher level text object would be at the embed character representing child text object that contains the caret.

For example, if the string "one two three" is implemented as a two text objects, with a top level text object containing an embed character "one ? three" and a child text object containing "two" and if the caret is in the descendant object just before the 'o' in "two", then:

the caretOffset for the "one ? three" object would be 4, matching the embed character
the caretOffset for "two" would be 2, matching the "o"

The caret position/offset is that of the character logically following it, e.g. to the right of it in a left to right language, or to the left of it in a right to left language.

Parameters

[out] offset The returned offset is relative to the text represented by this object.

Return values

S_OK
S_FALSE	if the caret is not currently active on this object, i.e. the caret is located on some other object. The returned offset value will be -1.

Note: S_FALSE (and an offset of -1) will not be returned if the caret is somewhere in the text object or one of its descendants.

◆ characterExtents

long IAccessibleText::characterExtents([in] long offset, [in] IA2CoordinateType coordType, [out] long x, [out] long y, [out] long width)

get

Returns the bounding box of the specified position.

The virtual character after the last character of the represented text, i.e. the one at position length is a special case. It represents the current input position and will therefore typically be queried by AT more often than other positions. Because it does not represent an existing character its bounding box is defined in relation to preceding characters. It should be roughly equivalent to the bounding box of some character when inserted at the end of the text. Its height typically being the maximal height of all the characters in the text or the height of the preceding character, its width being at least one pixel so that the bounding box is not degenerate.

Note that the index 'length' is not always valid. Whether it is or not is implementation dependent. It typically is when text is editable or otherwise when on the screen the caret can be placed behind the text. You can be sure that the index is valid after you have received a ::IA2_EVENT_TEXT_CARET_MOVED event for this index.

Parameters

[in]	offset	Index of the character for which to return its bounding box. The valid range is 0..length. Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.
[in]	coordType	Specifies if the coordinates are relative to the screen or to the parent window.
[out]	x	X coordinate of the top left corner of the bounding box of the referenced character.
[out]	y	Y coordinate of the top left corner of the bounding box of the referenced character.
[out]	width	Width of the bounding box of the referenced character.
[out]	height	Height of the bounding box of the referenced character.

Return values

S_OK
E_INVALIDARG	if bad [in] passed

◆ nCharacters

long IAccessibleText::nCharacters

get

Returns total number of characters.

Note that this may be different than the total number of bytes required to store the text, if the text contains multi-byte characters.

Parameters

[out] nCharacters

Return values

S_OK

◆ newText

IA2TextSegment IAccessibleText::newText

get

Returns any inserted text.

Provided for use by the ::IA2_EVENT_TEXT_INSERTED and ::IA2_EVENT_TEXT_UPDATED event handlers.

This data is only guaranteed to be valid while the thread notifying the event continues. Once the handler has returned, the validity of the data depends on how the server manages the life cycle of its objects. Also, note that the server may have different life cycle management strategies for controls depending on whether or not a control manages its children. Lists, trees, and tables can have a large number of children and thus it's possible that the child objects for those controls would only be created as needed. Servers should document their life cycle strategy as this will be of interest to assistive technology or script engines accessing data out of process or from other threads. Servers only need to save the last inserted block of text and a scope of the entire application is adequate.

Parameters

[out] newText The text that was just inserted.

Return values

S_OK
S_FALSE	If there is nothing to return, the values of IA2TextSegment struct are set as follows: text = NULL, start = 0, end = 0.

◆ nSelections

long IAccessibleText::nSelections

get

Returns the number of active non-contiguous selections.

Parameters

[out] nSelections

Return values

S_OK

◆ offsetAtPoint

long IAccessibleText::offsetAtPoint([in] long x, [in] long y, [in] IA2CoordinateType coordType)

get

Returns the text position for the specified screen position.

Given a point return the zero-based index of the character under that point. The same functionality could be achieved by using the bounding boxes for each character as returned by IAccessibleText::characterExtents. The method IAccessibleText::offsetAtPoint, however, can be implemented more efficiently.

Parameters

[in]	x	The position's x value for which to look up the index of the character that is rendered on to the display at that point.
[in]	y	The position's y value for which to look up the index of the character that is rendered on to the display at that point.
[in]	coordType	Screen coordinates or window coordinates.
[out]	offset	Index of the character under the given point or -1 if the point is invalid or there is no character under the point.

Return values

S_OK
S_FALSE	if nothing to return, [out] value is -1
E_INVALIDARG	if bad [in] passed

◆ oldText

IA2TextSegment IAccessibleText::oldText

get

Returns any removed text.

Provided for use by the IA2_EVENT_TEXT_REMOVED/UPDATED event handlers.

This data is only guaranteed to be valid while the thread notifying the event continues. Once the handler has returned, the validity of the data depends on how the server manages the life cycle of its objects. Also, note that the server may have different life cycle management strategies for controls depending on whether or not a control manages its children. Lists, trees, and tables can have a large number of children and thus it's possible that the child objects for those controls would only be created as needed. Servers should document their life cycle strategy as this will be of interest to assistive technology or script engines accessing data out of process or from other threads. Servers only need to save the last removed block of text and a scope of the entire application is adequate.

Parameters

[out] oldText The text that was just removed.

Return values

S_OK
S_FALSE	If there is nothing to return, the values of IA2TextSegment struct are set as follows: text = NULL, start = 0, end = 0.

◆ selection

long IAccessibleText::selection([in] long selectionIndex, [out] long startOffset)

get

Returns the character offsets of Nth active text selection.

Returns the 0-based starting and ending offsets of the Nth selection. If the text is implemented as a tree of text objects with embed characters in higher levels representing substrings of child text objects, consider the following. If the starting selection offset is in one of the child text objects, then the starting offset in the higher level text object would be at the embed character representing the child text object that contains the starting selection offset. If the ending selection offset is in one of the child text objects, then the ending offset in the higher level text object would be just after the embed character representing the child text object that contains the ending selection offset.

For example, if the string "one two three" is implemented as a two text objects, with a top level text object containing an embed character "one ? three" and a child text object containing "two" and if the selection is the string "two" then:

the startOffset for the "one ? three" object would be 4, matching the embed character and the endOffset would be 5.
the startOffset for the "two" object would be 0, and the endOffset would be 3

Selection offsets are that of the character logically following it, e.g. to the right of it in a left to right language or to the left of it in a right to left language.

Parameters

[in]	selectionIndex	Index of selection (0 based).
[out]	startOffset	0 based offset of first selected character
[out]	endOffset	0 based offset of one past the last selected character.

Return values

S_OK
E_INVALIDARG	if bad [in] passed

◆ text

BSTR IAccessibleText::text([in] long startOffset, [in] long endOffset)

get

Returns the substring between the two given indices.

The substring starts with the character at startOffset (inclusive) and up to the character at endOffset (exclusive), if startOffset is less or equal endOffset. If endOffset is lower than startOffset, the result is the same as a call with the two arguments being exchanged.

The whole text can be requested by passing the indices zero and IAccessibleText::nCharacters. If both indices have the same value, an empty string is returned.

Parameters

[in]	startOffset	Index of the first character to include in the returned string. The valid range is 0..length.
[in]	endOffset	Index of the last character to exclude in the returned string. The valid range is 0..length.
[out]	text	Returns the substring starting with the character at startOffset (inclusive) and up to the character at endOffset (exclusive), if startOffset is less than or equal to endOffset.

Return values

S_OK
E_INVALIDARG	if bad [in] passed

Note

The returned string may be longer than endOffset-startOffset bytes if text contains multi-byte characters.
Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.

◆ textAfterOffset

BSTR IAccessibleText::textAfterOffset([in] long offset, [in] IA2TextBoundaryType boundaryType, [out] long startOffset, [out] long endOffset)

get

Returns a text portion after the given position.

Returns the substring of the specified text type that is located after the given character and does not include it. The result of this method should be same as a result for IAccessibleText::textAtOffset with a suitably increased index value.

For example, if text type is IA2_TEXT_BOUNDARY_WORD, then the complete word that is closest to and located after offset is returned.

If the index is valid, but no text is found, S_FALSE is returned along with out values of 0, 0, and a NULL pointer. This would happen for boundary types other than character when the text consists entirely of whitespace.

Parameters

[in]	offset	Index of the character for which to return the text part after it. The index character will not be part of the returned string. The valid range is 0..length. Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.
[in]	boundaryType	The type of the text portion to return. See IA2TextBoundaryType for the complete list.
[out]	startOffset	0 based offset of first character.
[out]	endOffset	0 based offset of one past the last character.
[out]	text	Returns the requested text portion. This portion may be empty or invalid when no appropriate text portion is found or text type is invalid.

Return values

S_OK
S_FALSE	if the requested boundary type is not implemented, such as IA2_TEXT_BOUNDARY_SENTENCE, or if there is nothing to return; [out] values are 0s and NULL respectively
E_INVALIDARG	if bad [in] passed

◆ textAtOffset

BSTR IAccessibleText::textAtOffset([in] long offset, [in] IA2TextBoundaryType boundaryType, [out] long startOffset, [out] long endOffset)

get

Returns a text portion that spans the given position.

Returns the substring defined by the specified boundary type at the specified offset. Refer to IA2TextBoundaryType for more details.

For the word boundary type the returned string will contain the word at the offset if the offset is inside a word and will contain the word before the offset if the offset is not inside a word. All offsets from the first to the last characters of a word are considered inside the word. Boundary types of sentence and paragraph should exhibit similar behavior.

If the index is valid, but no text is found, S_FALSE is returned along with out values of 0, 0, and a NULL pointer. This would happen for boundary types other than character when the text consists entirely of whitespace.

Parameters

[in]	offset	Index of the character for which to return the text part it belongs to. The valid range is 0..length. Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.
[in]	boundaryType	The type of the text portion to return. See IA2TextBoundaryType for the complete list.
[out]	startOffset	0 based offset of first character.
[out]	endOffset	0 based offset of one past the last character.
[out]	text	Returns the requested text portion. This portion may be empty or invalid when no appropriate text portion is found or text type is invalid.

Return values

S_OK
S_FALSE	if the requested boundary type is not implemented, such as IA2_TEXT_BOUNDARY_SENTENCE, or if there is nothing to return; [out] values are 0s and NULL respectively
E_INVALIDARG	if bad [in] passed

◆ textBeforeOffset

BSTR IAccessibleText::textBeforeOffset([in] long offset, [in] IA2TextBoundaryType boundaryType, [out] long startOffset, [out] long endOffset)

get

Returns a text portion before the given position.

Returns the substring of the specified text type that is located before the given character and does not include it. The result of this method should be same as a result for IAccessibleText::textAtOffset with a suitably decreased index value.

For example, if text type is IA2_TEXT_BOUNDARY_WORD, then the complete word that is closest to and located before offset is returned.

If the index is valid, but no text is found, S_FALSE is returned along with out values of 0, 0, and a NULL pointer. This would happen for boundary types other than character when the text consists entirely of whitespace.

Parameters

[in]	offset	Index of the character for which to return the text part before it. The index character will not be part of the returned string. The valid range is 0..length. Refer to Special Offsets for use in the IAccessibleText and IAccessibleEditableText Methods for information about special offsets that can be used in IAccessibleText methods.
[in]	boundaryType	The type of the text portion to return. See IA2TextBoundaryType for the complete list.
[out]	startOffset	0 based offset of first character.
[out]	endOffset	0 based offset of one past the last character.
[out]	text	Returns the requested text portion. This portion may be empty or invalid when no appropriate text portion is found or text type is invalid.

Return values

S_OK
S_FALSE	if the requested boundary type is not implemented, such as IA2_TEXT_BOUNDARY_SENTENCE, or if there is nothing to return; [out] values are 0s and NULL respectively
E_INVALIDARG	if bad [in] passed

The documentation for this interface was generated from the following file:

Source/WebKit/win/Interfaces/Accessible2/AccessibleText.idl

Public Member Functions

Properties

Detailed Description

Member Function Documentation

◆ addSelection()

◆ removeSelection()

◆ scrollSubstringTo()

◆ scrollSubstringToPoint()

◆ setCaretOffset()

◆ setSelection()

Property Documentation

◆ attributes

◆ caretOffset

◆ characterExtents

◆ nCharacters

◆ newText

◆ nSelections

◆ offsetAtPoint

◆ oldText

◆ selection

◆ text

◆ textAfterOffset

◆ textAtOffset

◆ textBeforeOffset