static byte[] TryFixNameTable(ref byte[] data)
{
/*
* For a font to render properly in the XAML engine it requires
* a FamilyName to be properly set in the font's 'name' table.
* It is valid to not have this value set and web fonts may
* intentionally leave this blank as most web-font renderers will
* work fine without it. However as we need it to get XAML to render
* the font we need to manually pull the font name out from somewhere
* else and stick it in the expected place.
*/
using var ms = new MemoryStream(data);
using var t = new BEBinaryReader(ms);
var version = t.ReadUInt16();
if (version == 0)
{
var count = t.ReadUInt16();
var offset = t.ReadUInt16();
var recs = Enumerable.Range(0, count).Select(_ =>
{
return(new NameRecord
{
PlatformId = t.ReadUInt16(),
EncodingId = t.ReadUInt16(),
LangId = t.ReadUInt16(),
NameId = t.ReadUInt16(),
Length = t.ReadUInt16(),
Offset = t.ReadUInt16()
});
}).ToList();
// Debug code to view table data.
//var options = recs.Where(r => r.PlatformId == 3).ToList();
//var ns = recs.Where(r => r.NameId == 1).ToList();
//foreach (var rec in recs)
//{
// ms.Seek(rec.Offset + offset, SeekOrigin.Begin);
// byte[] buf = t.ReadBytes(rec.Length);
// Encoding enc2;
// if (rec.EncodingId == 3 || rec.EncodingId == 1)
// {
// enc2 = Encoding.BigEndianUnicode;
// }
// else
// {
// enc2 = Encoding.UTF8;
// }
// string strRet = enc2.GetString(buf, 0, buf.Length);
// System.Diagnostics.Debug.WriteLine(strRet);
//}
var fam = recs.FirstOrDefault(r => r.PlatformId == 3 && r.NameId == 1);
var post = recs.FirstOrDefault(r => r.NameId == 6);
if (fam is not null && post is not null &&
fam.Length == 0 && post.Length != 0)
{
fam.Length = post.Length;
fam.Offset = post.Offset;
}
else
{
return(null);
}
using var mso = new MemoryStream();
using var w = new BEBinaryWriter(mso);
w.Write(version);
w.Write(count);
w.Write(offset);
foreach (var r in recs)
{
w.Write(r.PlatformId);
w.Write(r.EncodingId);
w.Write(r.LangId);
w.Write(r.NameId);
w.Write(r.Length);
w.Write(r.Offset);
}
w.Flush();
ms.Seek(offset, SeekOrigin.Begin);
ms.CopyTo(mso);
mso.Flush();
return(mso.ToArray());
}
public static ConversionStatus Convert(
Stream input,
Stream output)
{
using var reader = new BEBinaryReader(input);
var header = new WoffHeader
{
Signature = reader.ReadUInt32(),
Flavor = reader.ReadUInt32(),
Length = reader.ReadUInt32(),
TableCount = reader.ReadUInt16(),
Reserved = reader.ReadUInt16(),
TotalSfntSize = reader.ReadUInt32(),
MajorVersion = reader.ReadUInt16(),
MinorVersion = reader.ReadUInt16(),
MetaOffset = reader.ReadUInt32(),
MetaLength = reader.ReadUInt32(),
MetaOrignalLength = reader.ReadUInt32(),
PrivOffset = reader.ReadUInt32(),
PrivLength = reader.ReadUInt32()
};
if (header.Signature is not 0x774F4646)
{
if (header.Signature is 0x774F4632)
{
return(ConversionStatus.UnsupportedWOFF2);
}
else
{
return(ConversionStatus.UnrecognisedFile);
}
}
UInt32 offset = 12;
// Read Table Headers
List <TableDirectory> entries = new List <TableDirectory>();
for (var i = 0; i < header.TableCount; i++)
{
var entry = new TableDirectory
{
Tag = reader.ReadUInt32(),
Offset = reader.ReadUInt32(),
CompressedLength = reader.ReadUInt32(),
OriginalLength = reader.ReadUInt32(),
OriginalChecksum = reader.ReadUInt32()
};
if (Name(entry.Tag) == "DSIG") // Conversion invalidates
{
continue;
}
entries.Add(entry);
offset += (4 * 4);
}
// Amend table count after removing DSIG
header.TableCount = (ushort)entries.Count;
// Calculate header values
UInt16 entrySelector = 0;
while (Math.Pow(2, entrySelector) <= header.TableCount)
{
entrySelector++;
}
entrySelector--;
UInt16 searchRange = (UInt16)(Math.Pow(2, entrySelector) * 16);
UInt16 rangeShift = (UInt16)(header.TableCount * 16 - searchRange);
// Create writer
using var writer = new BEBinaryWriter(output);
// Write Font Header
writer.Write(header.Flavor);
writer.Write(header.TableCount);
writer.Write(searchRange);
writer.Write(entrySelector);
writer.Write(rangeShift);
// Write Table Headers
foreach (var entry in entries)
{
writer.Write(entry.Tag);
writer.Write(entry.OriginalChecksum);
writer.Write(offset);
writer.Write(entry.OriginalLength);
entry.OutputOffset = offset;
offset += entry.OriginalLength;
if ((offset % 4) != 0)
{
offset += 4 - (offset % 4);
}
}
// Write Table contents
foreach (var entry in entries)
{
input.Seek(entry.Offset, SeekOrigin.Begin);
byte[] compressed = reader.ReadBytes((int)entry.CompressedLength);
byte[] uncompressed;
if (entry.CompressedLength != entry.OriginalLength)
{
// Decompress table
using var comp = new MemoryStream(compressed.AsSpan().Slice(2).ToArray()); // Ignore the ZLib header (2 bytes long)
using var outs = new MemoryStream();
using var def = new DeflateStream(comp, CompressionMode.Decompress);
def.CopyTo(outs);
uncompressed = outs.ToArray();
}
else
{
uncompressed = compressed;
}
if (uncompressed.Length != entry.OriginalLength)
{
return(ConversionStatus.TableLengthMismatch);
}
if (entry.ToString() == "name")
{
if (TryFixNameTable(ref uncompressed) is byte[] ammended)
{
uncompressed = ammended;
}
}
output.Seek(entry.OutputOffset, SeekOrigin.Begin);
writer.Write(uncompressed);
offset = (uint)output.Position;
if (offset % 4 != 0)
{
uint padding = 4 - (offset % 4);
writer.Write(new byte[padding]);
}
}
writer.Flush();
output.Flush();
return(ConversionStatus.OK);
}
