public static uint[] ReadTTCHeader(DataReader reader)
{
// read the file header; if we have a collection, we want to
// figure out where all the different faces are in the file
// if we don't have a collection, there's just one font in the file
var tag = reader.ReadUInt32();
if (tag != FourCC.Ttcf)
return new[] { 0u };
// font file is a TrueType collection; read the TTC header
reader.Skip(4); // version number
var count = reader.ReadUInt32BE();
if (count == 0 || count > MaxFontsInCollection)
throw new InvalidFontException("Invalid TTC header");
var offsets = new uint[count];
for (int i = 0; i < count; i++)
offsets[i] = reader.ReadUInt32BE();
return offsets;
}
public static TableRecord[] ReadFaceHeader(DataReader reader)
{
var tag = reader.ReadUInt32BE();
if (tag != TTFv1 && tag != TTFv2 && tag != FourCC.True)
throw new InvalidFontException("Unknown or unsupported sfnt version.");
var tableCount = reader.ReadUInt16BE();
reader.Skip(6); // skip the rest of the header
// read each font table descriptor
var tables = new TableRecord[tableCount];
for (int i = 0; i < tableCount; i++)
{
tables[i] = new TableRecord
{
Tag = reader.ReadUInt32(),
CheckSum = reader.ReadUInt32BE(),
Offset = reader.ReadUInt32BE(),
Length = reader.ReadUInt32BE(),
};
}
return tables;
}
