FontCollectionHeader ReadTTCHeader(ByteOrderSwappingBinaryReader input)
{
//https://docs.microsoft.com/en-us/typography/opentype/spec/otff#ttc-header
//TTC Header Version 1.0:
//Type Name Description
//TAG ttcTag Font Collection ID string: 'ttcf' (used for fonts with CFF or CFF2 outlines as well as TrueType outlines)
//uint16 majorVersion Major version of the TTC Header, = 1.
//uint16 minorVersion Minor version of the TTC Header, = 0.
//uint32 numFonts Number of fonts in TTC
//Offset32 offsetTable[numFonts] Array of offsets to the OffsetTable for each font from the beginning of the file
//TTC Header Version 2.0:
//Type Name Description
//TAG ttcTag Font Collection ID string: 'ttcf'
//uint16 majorVersion Major version of the TTC Header, = 2.
//uint16 minorVersion Minor version of the TTC Header, = 0.
//uint32 numFonts Number of fonts in TTC
//Offset32 offsetTable[numFonts] Array of offsets to the OffsetTable for each font from the beginning of the file
//uint32 dsigTag Tag indicating that a DSIG table exists, 0x44534947 ('DSIG') (null if no signature)
//uint32 dsigLength The length (in bytes) of the DSIG table (null if no signature)
//uint32 dsigOffset The offset (in bytes) of the DSIG table from the beginning of the TTC file (null if no signature)
var ttcHeader = new FontCollectionHeader();
ttcHeader.majorVersion = input.ReadUInt16();
ttcHeader.minorVersion = input.ReadUInt16();
uint numFonts = input.ReadUInt32();
int[] offsetTables = new int[numFonts];
for (uint i = 0; i < numFonts; ++i)
{
offsetTables[i] = input.ReadInt32();
}
ttcHeader.numFonts = numFonts;
ttcHeader.offsetTables = offsetTables;
//
if (ttcHeader.majorVersion == 2)
{
ttcHeader.dsigTag = input.ReadUInt32();
ttcHeader.dsigLength = input.ReadUInt32();
ttcHeader.dsigOffset = input.ReadUInt32();
if (ttcHeader.dsigTag == 0x44534947)
{
//Tag indicating that a DSIG table exists
//TODO: goto DSIG add read signature
}
}
return(ttcHeader);
}
/// <summary>
/// read only name entry
/// </summary>
/// <param name="stream"></param>
/// <returns></returns>
public PreviewFontInfo ReadPreview(Stream stream)
{
//var little = BitConverter.IsLittleEndian;
using (var input = new ByteOrderSwappingBinaryReader(stream))
{
ushort majorVersion = input.ReadUInt16();
ushort minorVersion = input.ReadUInt16();
if (KnownFontFiles.IsTtcf(majorVersion, minorVersion))
{
//this font stream is 'The Font Collection'
FontCollectionHeader ttcHeader = ReadTTCHeader(input);
PreviewFontInfo[] members = new PreviewFontInfo[ttcHeader.numFonts];
for (uint i = 0; i < ttcHeader.numFonts; ++i)
{
input.BaseStream.Seek(ttcHeader.offsetTables[i], SeekOrigin.Begin);
PreviewFontInfo member = members[i] = ReadActualFontPreview(input, false);
member.ActualStreamOffset = ttcHeader.offsetTables[i];
}
return(new PreviewFontInfo(BuildTtcfName(members), members));
}
else if (KnownFontFiles.IsWoff(majorVersion, minorVersion))
{
//check if we enable woff or not
WebFont.WoffReader woffReader = new WebFont.WoffReader();
input.BaseStream.Position = 0;
return(woffReader.ReadPreview(input));
}
else if (KnownFontFiles.IsWoff2(majorVersion, minorVersion))
{
//check if we enable woff2 or not
WebFont.Woff2Reader woffReader = new WebFont.Woff2Reader();
input.BaseStream.Position = 0;
return(woffReader.ReadPreview(input));
}
else
{
return(ReadActualFontPreview(input, true));//skip version data (majorVersion, minorVersion)
}
}
}
