/// <summary>
/// Maps a unicode to the index of the corresponding glyph.
/// See OpenType spec "cmap - Character To Glyph Index Mapping Table / Format 4: Segment mapping to delta values"
/// for details about this a little bit strange looking algorithm.
/// </summary>
public int CharCodeToGlyphIndex(char value)
{
try
{
CMap4 cmap = FontFace.cmap.cmap4;
int segCount = cmap.segCountX2 / 2;
int seg;
for (seg = 0; seg < segCount; seg++)
{
if (value <= cmap.endCount[seg])
{
break;
}
}
Debug.Assert(seg < segCount);
if (value < cmap.startCount[seg])
{
return(0);
}
if (cmap.idRangeOffs[seg] == 0)
{
return((value + cmap.idDelta[seg]) & 0xFFFF);
}
int idx = cmap.idRangeOffs[seg] / 2 + (value - cmap.startCount[seg]) - (segCount - seg);
Debug.Assert(idx >= 0 && idx < cmap.glyphCount);
return(cmap.glyphIdArray[idx] == 0 ? 0 : (cmap.glyphIdArray[idx] + cmap.idDelta[seg]) & 0xFFFF);
}
catch
{
GetType();
throw;
}
}