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);
}
public unsafe static SbitTable Read(DataReader reader, TableRecord[] tables)
{
if (!SfntTables.SeekToTable(reader, tables, FourCC.Eblc))
return null;
// skip version
var baseOffset = reader.Position;
reader.Skip(sizeof(int));
// load each strike table
var count = reader.ReadInt32BE();
if (count > MaxBitmapStrikes)
throw new InvalidFontException("Too many bitmap strikes in font.");
var sizeTableHeaders = stackalloc BitmapSizeTable[count];
for (int i = 0; i < count; i++)
{
sizeTableHeaders[i].SubTableOffset = reader.ReadUInt32BE();
sizeTableHeaders[i].SubTableSize = reader.ReadUInt32BE();
sizeTableHeaders[i].SubTableCount = reader.ReadUInt32BE();
// skip colorRef, metrics entries, start and end glyph indices
reader.Skip(sizeof(uint) + sizeof(ushort) * 2 + 12 * 2);
sizeTableHeaders[i].PpemX = reader.ReadByte();
sizeTableHeaders[i].PpemY = reader.ReadByte();
sizeTableHeaders[i].BitDepth = reader.ReadByte();
sizeTableHeaders[i].Flags = (BitmapSizeFlags)reader.ReadByte();
}
// read index subtables
var indexSubTables = stackalloc IndexSubTable[count];
for (int i = 0; i < count; i++)
{
reader.Seek(baseOffset + sizeTableHeaders[i].SubTableOffset);
indexSubTables[i] = new IndexSubTable
{
FirstGlyph = reader.ReadUInt16BE(),
LastGlyph = reader.ReadUInt16BE(),
Offset = reader.ReadUInt32BE()
};
}
// read the actual data for each strike table
for (int i = 0; i < count; i++)
{
// read the subtable header
reader.Seek(baseOffset + sizeTableHeaders[i].SubTableOffset + indexSubTables[i].Offset);
var indexFormat = reader.ReadUInt16BE();
var imageFormat = reader.ReadUInt16BE();
var imageDataOffset = reader.ReadUInt32BE();
}
return null;
}
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 void ReadPost(DataReader reader, TableRecord[] tables, ref FaceHeader header)
{
if (!SeekToTable(reader, tables, FourCC.Post))
{
return;
}
// skip over version and italicAngle
reader.Skip(sizeof(int) * 2);
header.UnderlinePosition = reader.ReadInt16BE();
header.UnderlineThickness = reader.ReadInt16BE();
header.IsFixedPitch = reader.ReadUInt32BE() != 0;
}
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;
}
public static void ReadLoca(DataReader reader, TableRecord[] tables, IndexFormat format, uint *table, int count)
{
SeekToTable(reader, tables, FourCC.Loca, required: true);
if (format == IndexFormat.Short)
{
// values are ushort, divided by 2, so we need to shift back
for (int i = 0; i < count; i++)
{
*table++ = (uint)(reader.ReadUInt16BE() << 1);
}
}
else
{
for (int i = 0; i < count; i++)
{
*table++ = reader.ReadUInt32BE();
}
}
}
public static CharacterMap ReadCmap(DataReader reader, TableRecord[] tables)
{
SfntTables.SeekToTable(reader, tables, FourCC.Cmap, required: true);
// skip version
var cmapOffset = reader.Position;
reader.Skip(sizeof(short));
// read all of the subtable headers
var subtableCount = reader.ReadUInt16BE();
var subtableHeaders = new CmapSubtableHeader[subtableCount];
for (int i = 0; i < subtableHeaders.Length; i++)
{
subtableHeaders[i] = new CmapSubtableHeader
{
PlatformID = reader.ReadUInt16BE(),
EncodingID = reader.ReadUInt16BE(),
Offset = reader.ReadUInt32BE()
};
}
// search for a "full" Unicode table first
var chosenSubtableOffset = 0u;
for (int i = 0; i < subtableHeaders.Length; i++)
{
var platform = subtableHeaders[i].PlatformID;
var encoding = subtableHeaders[i].EncodingID;
if ((platform == PlatformID.Microsoft && encoding == WindowsEncoding.UnicodeFull) ||
(platform == PlatformID.Unicode && encoding == UnicodeEncoding.Unicode32))
{
chosenSubtableOffset = subtableHeaders[i].Offset;
break;
}
}
// if no full unicode table, just grab the first
// one that supports any flavor of Unicode
if (chosenSubtableOffset == 0)
{
for (int i = 0; i < subtableHeaders.Length; i++)
{
var platform = subtableHeaders[i].PlatformID;
var encoding = subtableHeaders[i].EncodingID;
if ((platform == PlatformID.Microsoft && encoding == WindowsEncoding.UnicodeBmp) ||
platform == PlatformID.Unicode)
{
chosenSubtableOffset = subtableHeaders[i].Offset;
break;
}
}
}
// no unicode support at all is an error
if (chosenSubtableOffset == 0)
{
throw new Exception("Font does not support Unicode.");
}
// jump to our chosen table and find out what format it's in
reader.Seek(cmapOffset + chosenSubtableOffset);
var format = reader.ReadUInt16BE();
switch (format)
{
case 4: return(ReadCmapFormat4(reader));
default: throw new Exception("Unsupported cmap format.");
}
}
public unsafe static SbitTable Read(DataReader reader, TableRecord[] tables)
{
if (!SfntTables.SeekToTable(reader, tables, FourCC.Eblc))
{
return(null);
}
// skip version
var baseOffset = reader.Position;
reader.Skip(sizeof(int));
// load each strike table
var count = reader.ReadInt32BE();
if (count > MaxBitmapStrikes)
{
throw new Exception("Too many bitmap strikes in font.");
}
var sizeTableHeaders = stackalloc BitmapSizeTable[count];
for (int i = 0; i < count; i++)
{
sizeTableHeaders[i].SubTableOffset = reader.ReadUInt32BE();
sizeTableHeaders[i].SubTableSize = reader.ReadUInt32BE();
sizeTableHeaders[i].SubTableCount = reader.ReadUInt32BE();
// skip colorRef, metrics entries, start and end glyph indices
reader.Skip(sizeof(uint) + sizeof(ushort) * 2 + 12 * 2);
sizeTableHeaders[i].PpemX = reader.ReadByte();
sizeTableHeaders[i].PpemY = reader.ReadByte();
sizeTableHeaders[i].BitDepth = reader.ReadByte();
sizeTableHeaders[i].Flags = (BitmapSizeFlags)reader.ReadByte();
}
// read index subtables
var indexSubTables = stackalloc IndexSubTable[count];
for (int i = 0; i < count; i++)
{
reader.Seek(baseOffset + sizeTableHeaders[i].SubTableOffset);
indexSubTables[i] = new IndexSubTable
{
FirstGlyph = reader.ReadUInt16BE(),
LastGlyph = reader.ReadUInt16BE(),
Offset = reader.ReadUInt32BE()
};
}
// read the actual data for each strike table
for (int i = 0; i < count; i++)
{
// read the subtable header
reader.Seek(baseOffset + sizeTableHeaders[i].SubTableOffset + indexSubTables[i].Offset);
var indexFormat = reader.ReadUInt16BE();
var imageFormat = reader.ReadUInt16BE();
var imageDataOffset = reader.ReadUInt32BE();
}
return(null);
}
public static CharacterMap ReadCmap(DataReader reader, TableRecord[] tables)
{
SfntTables.SeekToTable(reader, tables, FourCC.Cmap, required: true);
// skip version
var cmapOffset = reader.Position;
reader.Skip(sizeof(short));
// read all of the subtable headers
var subtableCount = reader.ReadUInt16BE();
var subtableHeaders = new CmapSubtableHeader[subtableCount];
for (int i = 0; i < subtableHeaders.Length; i++)
{
subtableHeaders[i] = new CmapSubtableHeader
{
PlatformID = reader.ReadUInt16BE(),
EncodingID = reader.ReadUInt16BE(),
Offset = reader.ReadUInt32BE()
};
}
// search for a "full" Unicode table first
var chosenSubtableOffset = 0u;
for (int i = 0; i < subtableHeaders.Length; i++)
{
var platform = subtableHeaders[i].PlatformID;
var encoding = subtableHeaders[i].EncodingID;
if ((platform == PlatformID.Microsoft && encoding == WindowsEncoding.UnicodeFull) ||
(platform == PlatformID.Unicode && encoding == UnicodeEncoding.Unicode32))
{
chosenSubtableOffset = subtableHeaders[i].Offset;
break;
}
}
// if no full unicode table, just grab the first
// one that supports any flavor of Unicode
if (chosenSubtableOffset == 0)
{
for (int i = 0; i < subtableHeaders.Length; i++)
{
var platform = subtableHeaders[i].PlatformID;
var encoding = subtableHeaders[i].EncodingID;
if ((platform == PlatformID.Microsoft && encoding == WindowsEncoding.UnicodeBmp) ||
platform == PlatformID.Unicode)
{
chosenSubtableOffset = subtableHeaders[i].Offset;
break;
}
}
}
// no unicode support at all is an error
if (chosenSubtableOffset == 0)
throw new Exception("Font does not support Unicode.");
// jump to our chosen table and find out what format it's in
reader.Seek(cmapOffset + chosenSubtableOffset);
var format = reader.ReadUInt16BE();
switch (format)
{
case 4: return ReadCmapFormat4(reader);
default: throw new Exception("Unsupported cmap format.");
}
}
public static void ReadLoca(DataReader reader, TableRecord[] tables, IndexFormat format, uint* table, int count)
{
SeekToTable(reader, tables, FourCC.Loca, required: true);
if (format == IndexFormat.Short)
{
// values are ushort, divided by 2, so we need to shift back
for (int i = 0; i < count; i++)
*table++ = (uint)(reader.ReadUInt16BE() << 1);
}
else
{
for (int i = 0; i < count; i++)
*table++ = reader.ReadUInt32BE();
}
}
public static void ReadPost(DataReader reader, TableRecord[] tables, ref FaceHeader header)
{
if (!SeekToTable(reader, tables, FourCC.Post))
return;
// skip over version and italicAngle
reader.Skip(sizeof(int) * 2);
header.UnderlinePosition = reader.ReadInt16BE();
header.UnderlineThickness = reader.ReadInt16BE();
header.IsFixedPitch = reader.ReadUInt32BE() != 0;
}
