private byte[] BuildHmtxTable()
{
MemoryStream bos = new MemoryStream();
HorizontalHeaderTable h = ttf.HorizontalHeader;
HorizontalMetricsTable hm = ttf.HorizontalMetrics;
Bytes.Buffer input = ttf.OriginalData;
// more info: https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6hmtx.html
int lastgid = h.NumberOfHMetrics - 1;
// true if lastgid input not in the set: we'll need its width (but not its left side bearing) later
bool needLastGidWidth = false;
if (glyphIds.LastOrDefault() > lastgid && !glyphIds.Contains(lastgid))
{
needLastGidWidth = true;
}
try
{
long isResult = input.Skip(hm.Offset);
if (isResult.CompareTo(hm.Offset) != 0)
{
Debug.WriteLine($"debug: Tried skipping {hm.Offset} bytes but only {isResult} bytes skipped");
}
long lastOffset = 0;
foreach (int glyphId in glyphIds)
{
// offset in original file
long offset;
if (glyphId <= lastgid)
{
// copy width and lsb
offset = glyphId * 4L;
lastOffset = CopyBytes(input, bos, offset, lastOffset, 4);
}
else
{
if (needLastGidWidth)
{
// one time only: copy width from lastgid, whose width applies
// to all later glyphs
needLastGidWidth = false;
offset = lastgid * 4L;
lastOffset = CopyBytes(input, bos, offset, lastOffset, 2);
// then go on with lsb from actual glyph (lsb are individual even in monotype fonts)
}
// copy lsb only, as we are beyond numOfHMetrics
offset = h.NumberOfHMetrics * 4L + (glyphId - h.NumberOfHMetrics) * 2L;
lastOffset = CopyBytes(input, bos, offset, lastOffset, 2);
}
}
return(bos.ToArray());
}
finally
{
input.Dispose();
}
}
/**
* Resolve compound glyph references.
*/
private void AddCompoundReferences()
{
if (hasAddedCompoundReferences)
{
return;
}
hasAddedCompoundReferences = true;
bool hasNested;
do
{
GlyphTable g = ttf.Glyph;
long[] offsets = ttf.IndexToLocation.Offsets;
Bytes.Buffer input = ttf.OriginalData;
ISet <int> glyphIdsToAdd = null;
try
{
long isResult = input.Skip(g.Offset);
if (isResult.CompareTo(g.Offset) != 0)
{
Debug.WriteLine($"debug: Tried skipping {g.Offset} bytes but skipped only {isResult} bytes");
}
long lastOff = 0L;
foreach (int glyphId in glyphIds)
{
long offset = offsets[glyphId];
long len = offsets[glyphId + 1] - offset;
isResult = input.Skip(offset - lastOff);
if (isResult.CompareTo(offset - lastOff) != 0)
{
Debug.WriteLine($"debug: Tried skipping {(offset - lastOff)} bytes but skipped only {isResult} bytes");
}
sbyte[] buf = new sbyte[(int)len];
isResult = input.Read(buf);
if (isResult.CompareTo(len) != 0)
{
Debug.WriteLine($"debug: Tried reading {len} bytes but only {isResult} bytes read");
}
// rewrite glyphIds for compound glyphs
if (buf.Length >= 2 && buf[0] == -1 && buf[1] == -1)
{
int off = 2 * 5;
int flags;
do
{
flags = (buf[off] & 0xff) << 8 | buf[off + 1] & 0xff;
off += 2;
int ogid = (buf[off] & 0xff) << 8 | buf[off + 1] & 0xff;
if (!glyphIds.Contains(ogid))
{
if (glyphIdsToAdd == null)
{
glyphIdsToAdd = new HashSet <int>();
}
glyphIdsToAdd.Add(ogid);
}
off += 2;
// ARG_1_AND_2_ARE_WORDS
if ((flags & 1 << 0) != 0)
{
off += 2 * 2;
}
else
{
off += 2;
}
// WE_HAVE_A_TWO_BY_TWO
if ((flags & 1 << 7) != 0)
{
off += 2 * 4;
}
// WE_HAVE_AN_X_AND_Y_SCALE
else if ((flags & 1 << 6) != 0)
{
off += 2 * 2;
}
// WE_HAVE_A_SCALE
else if ((flags & 1 << 3) != 0)
{
off += 2;
}
}while ((flags & 1 << 5) != 0); // MORE_COMPONENTS
}
lastOff = offsets[glyphId + 1];
}
}
finally
{
input.Dispose();
}
if (glyphIdsToAdd != null)
{
glyphIds.AddAll(glyphIdsToAdd);
}
hasNested = glyphIdsToAdd != null;
}while (hasNested);
}