gecko-dev/accessible/public/nsIAccessibleText.idl

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 * The Initial Developer of the Original Code is
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 * Contributor(s):
 *   Paul Sandoz (paul.sandoz@sun.com)
 *   Bill Haneman (bill.haneman@sun.com)
 *   John Gaunt (jgaunt@netscape.com)
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#include "nsISupports.idl"

typedef long nsAccessibleTextBoundary;
typedef long nsAccessibleCoordType;

interface nsIAccessible;

[scriptable, uuid(80e64909-e96b-45e9-81c9-3521a2dea7bb)]
interface nsIAccessibleText : nsISupports
{
  const nsAccessibleTextBoundary BOUNDARY_CHAR = 0;
  const nsAccessibleTextBoundary BOUNDARY_WORD_START = 1;
  const nsAccessibleTextBoundary BOUNDARY_WORD_END = 2;
  const nsAccessibleTextBoundary BOUNDARY_SENTENCE_START = 3;
  const nsAccessibleTextBoundary BOUNDARY_SENTENCE_END = 4;
  const nsAccessibleTextBoundary BOUNDARY_LINE_START = 5;
  const nsAccessibleTextBoundary BOUNDARY_LINE_END = 6;
  const nsAccessibleTextBoundary BOUNDARY_ATTRIBUTE_RANGE = 7;

  const nsAccessibleCoordType COORD_TYPE_SCREEN = 0;
  const nsAccessibleCoordType COORD_TYPE_WINDOW = 1;

  attribute long caretOffset;

  readonly attribute long characterCount;
  readonly attribute long selectionCount;

    /**
      * String methods may need to return multibyte-encoded strings,
      * since some locales can't be encoded using 16-bit chars.
      * So the methods below might return UTF-16 strings, or they could
      * return "string" values which are UTF-8.
      */
  AString getText (in long startOffset, in long endOffset);

  AString getTextAfterOffset (in long offset,
                              in nsAccessibleTextBoundary boundaryType,
                              out long startOffset,
                              out long endOffset);

  AString getTextAtOffset (in long offset,
                           in nsAccessibleTextBoundary boundaryType,
                           out long startOffset,
                           out long endOffset);

  AString getTextBeforeOffset (in long offset,
                               in nsAccessibleTextBoundary boundaryType,
                               out long startOffset,
                               out long endOffset);

    /**
      * It would be better to return an unsigned long here,
      * to allow unicode chars > 16 bits
      */
  wchar getCharacterAtOffset (in long offset);

  /**
   * Get the accessible and start/end offsets around the given offset.
   * This accessible get return the DOM node and layout frame
   * with the uniform attributes for this range of text
   */
  nsIAccessible getAttributeRange (in long offset,
                                   out long rangeStartOffset,
                                   out long rangeEndOffset);

  void getCharacterExtents (in long offset,
                            out long x,
                            out long y,
                            out long width,
                            out long height,
                            in nsAccessibleCoordType coordType);

  void getRangeExtents (in long startOffset,
                        in long endOffset,
                        out long x,
                        out long y,
                        out long width,
                        out long height,
                        in nsAccessibleCoordType coordType);

  /**
   * Get the text offset at the given point, or return -1
   * if no character exists at that point
   */
  long getOffsetAtPoint (in long x, in long y,
                         in nsAccessibleCoordType coordType);

  void getSelectionBounds (in long selectionNum,
                           out long startOffset,
                           out long endOffset);

  void setSelectionBounds (in long selectionNum,
                              in long startOffset,
                              in long endOffset);

  void addSelection (in long startOffset, in long endOffset);

  void removeSelection (in long selectionNum);
};

/*
 Assumptions:

 Using wstring (UCS2) instead of string encoded in UTF-8.
 Multibyte encodings (or at least potentially multi-byte
 encodings) would be preferred for the reasons cited above.

 The following methods will throw an exception on failure
 (since not every text component will allow every operation):
 setSelectionBounds, addSelection, removeSelection, setCaretOffset.

 getRangeAttributes defined to return an nsISupports
 interface instead of a pango specific data structure.
 It may be that some other return type is more appropriate
 for mozilla text attributes.

 we assume that all text components support the idea of
 a caret offset, whether visible or "virtual".  If this
 isn't the case, caretOffset can be made readonly and
 a setCaretOffset method provided which throws an exception
 on failure (as with *selection methods above).
*/