Mozilla2:GFXTextRun

Class gfxTextRun

gfxTextRun.h

class gfxTextRun {
  // these do not copy the text
  gfxTextRun(const char* ASCII, int length, nsIFontMetrics* font, nsIAtom* language);
  gfxTextRun(const PRUnichar* unicode, int length, nsIFontMetrics* font, nsIAtom* language);

  enum { ClusterStart = 0x1 } CharFlags;
  // ClusterStart: character is the first character of a cluster
  void GetCharacterFlags(int pos, int len, CharFlags* flags);

  void SetWordStartEnd(PRBool startsWord, PRBool endsWord);
  void SetLineStartEnd(PRBool startsLine, PRBool endsLine);

  // Set the spacing between clusters. For each character index i that is
  // the start of a cluster, spacingArray[i] is the amount of space to insert
  // before that cluster (possibly negative). For each character index i that
  // is not the start of a cluster, spacingArray[i] must be zero.
  // spacingArray[0] must be zero.
  void SetSpacing(gfxFloat* spacingArray);
         
  // The substring must not contain any partial clusters. 'pt' is the
  // the baseline of the visually left edge of the visually leftmost cluster.
  void Draw(gfxContext* ctx, gfxPoint& pt, int pos, int len);

  struct Dimensions {
    // start of the substring relative to the origin of the whole string
    gfxFloat xOffset;
    // width of the substring;
    gfxFloat width;
    // amount by which the glyphs visually extend to the left of xOffset and
    // to the right of xOffset+width
    gfxFloat leftBearing, rightBearing;
    // font ascent and descent for this substring
    gfxFloat ascent, descent;
    // visual ascent and descent for this substring (area actually drawn by
    // glyphs --- needed for MathML I think)
    gfxFloat visualAscent, visualDescent;
  };
  // The substring must not contain any partial clusters
  Dimensions MeasureText(int pos, int len);

  // Compute how many characters from this string starting at
  // character 'pos' and up to length 'len' fit
  // into the given width. 'breakflags' indicates our
  // preferences about where we allow breaks.
  // We will usually want to call MeasureText right afterwards,
  // the implementor could optimize for that.
  // The substring must not contain any partial clusters
  int GetCharsFit(int pos, int len, gfxFloat width, int breakflags);

  // If the user clicks the mouse at point pt, 
  int GetPositionInString(gfxPoint& pt);
};

See Gecko2:NewTextAPI