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 void ReadHead(DataReader reader, TableRecord[] tables, out FaceHeader header)
{
SeekToTable(reader, tables, FourCC.Head, required: true);
// 'head' table contains global information for the font face
// we only care about a few fields in it
reader.Skip(sizeof(int) * 4); // version, revision, checksum, magic number
header = new FaceHeader
{
Flags = (HeadFlags)reader.ReadUInt16BE(),
UnitsPerEm = reader.ReadUInt16BE()
};
if (header.UnitsPerEm == 0)
throw new InvalidFontException("Invalid 'head' table.");
// skip over created and modified times, bounding box,
// deprecated style bits, direction hints, and size hints
reader.Skip(sizeof(long) * 2 + sizeof(short) * 7);
header.IndexFormat = (IndexFormat)reader.ReadInt16BE();
}
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 static KerningTable ReadKern(DataReader reader, TableRecord[] tables)
{
// kern table is optional
if (!SfntTables.SeekToTable(reader, tables, FourCC.Kern))
return null;
// skip version
reader.Skip(sizeof(short));
// read each subtable and accumulate kerning values
var tableData = new Dictionary<uint, int>();
var subtableCount = reader.ReadUInt16BE();
for (int i = 0; i < subtableCount; i++)
{
// skip version
var currentOffset = reader.Position;
reader.Skip(sizeof(short));
var length = reader.ReadUInt16BE();
var coverage = reader.ReadUInt16BE();
// we (and Windows) only support Format 0 tables
// only care about tables with horizontal kerning data
var kc = (KernCoverage)coverage;
if ((coverage & FormatMask) == 0 && (kc & KernCoverage.Horizontal) != 0 && (kc & KernCoverage.CrossStream) == 0)
{
// read the number of entries; skip over the rest of the header
var entryCount = reader.ReadUInt16BE();
reader.Skip(sizeof(short) * 3);
var isMin = (kc & KernCoverage.Minimum) != 0;
var isOverride = (kc & KernCoverage.Override) != 0;
// read in each entry and accumulate its kerning data
for (int j = 0; j < entryCount; j++)
{
var left = reader.ReadUInt16BE();
var right = reader.ReadUInt16BE();
var value = reader.ReadInt16BE();
// look up the current value, if we have one; if not, start at zero
int current = 0;
var key = ((uint)left << 16) | right;
tableData.TryGetValue(key, out current);
if (isMin)
{
if (current < value)
tableData[key] = value;
}
else if (isOverride)
tableData[key] = value;
else
tableData[key] = current + value;
}
}
// jump to the next subtable
reader.Seek(currentOffset + length);
}
return new KerningTable(tableData);
}
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.");
}
}
static unsafe CharacterMap ReadCmapFormat4(DataReader reader)
{
// skip over length and language
reader.Skip(sizeof(short) * 2);
// figure out how many segments we have
var segmentCount = reader.ReadUInt16BE() / 2;
if (segmentCount > MaxSegments)
throw new Exception("Too many cmap segments.");
// skip over searchRange, entrySelector, and rangeShift
reader.Skip(sizeof(short) * 3);
// read in segment ranges
var endCount = stackalloc int[segmentCount];
for (int i = 0; i < segmentCount; i++)
endCount[i] = reader.ReadUInt16BE();
reader.Skip(sizeof(short)); // padding
var startCount = stackalloc int[segmentCount];
for (int i = 0; i < segmentCount; i++)
startCount[i] = reader.ReadUInt16BE();
var idDelta = stackalloc int[segmentCount];
for (int i = 0; i < segmentCount; i++)
idDelta[i] = reader.ReadInt16BE();
// build table from each segment
var table = new Dictionary<CodePoint, int>();
for (int i = 0; i < segmentCount; i++)
{
// read the "idRangeOffset" for the current segment
// if nonzero, we need to jump into the glyphIdArray to figure out the mapping
// the layout is bizarre; see the OpenType spec for details
var idRangeOffset = reader.ReadUInt16BE();
if (idRangeOffset != 0)
{
var currentOffset = reader.Position;
reader.Seek(currentOffset + idRangeOffset - sizeof(ushort));
var end = endCount[i];
var delta = idDelta[i];
for (var codepoint = startCount[i]; codepoint <= end; codepoint++)
{
var glyphId = reader.ReadUInt16BE();
if (glyphId != 0)
{
var glyphIndex = (glyphId + delta) & 0xFFFF;
if (glyphIndex != 0)
table.Add((CodePoint)codepoint, glyphIndex);
}
}
reader.Seek(currentOffset);
}
else
{
// otherwise, do a straight iteration through the segment
var end = endCount[i];
var delta = idDelta[i];
for (var codepoint = startCount[i]; codepoint <= end; codepoint++)
{
var glyphIndex = (codepoint + delta) & 0xFFFF;
if (glyphIndex != 0)
table.Add((CodePoint)codepoint, glyphIndex);
}
}
}
return new CharacterMap(table);
}
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);
}
unsafe static CharacterMap ReadCmapFormat4(DataReader reader)
{
// skip over length and language
reader.Skip(sizeof(short) * 2);
// figure out how many segments we have
var segmentCount = reader.ReadUInt16BE() / 2;
if (segmentCount > MaxSegments)
{
throw new InvalidFontException("Too many cmap segments.");
}
// skip over searchRange, entrySelector, and rangeShift
reader.Skip(sizeof(short) * 3);
// read in segment ranges
var endCount = stackalloc int[segmentCount];
for (int i = 0; i < segmentCount; i++)
{
endCount[i] = reader.ReadUInt16BE();
}
reader.Skip(sizeof(short)); // padding
var startCount = stackalloc int[segmentCount];
for (int i = 0; i < segmentCount; i++)
{
startCount[i] = reader.ReadUInt16BE();
}
var idDelta = stackalloc int[segmentCount];
for (int i = 0; i < segmentCount; i++)
{
idDelta[i] = reader.ReadInt16BE();
}
// build table from each segment
var table = new Dictionary <CodePoint, int>();
for (int i = 0; i < segmentCount; i++)
{
// read the "idRangeOffset" for the current segment
// if nonzero, we need to jump into the glyphIdArray to figure out the mapping
// the layout is bizarre; see the OpenType spec for details
var idRangeOffset = reader.ReadUInt16BE();
if (idRangeOffset != 0)
{
var currentOffset = reader.Position;
reader.Seek(currentOffset + idRangeOffset - sizeof(ushort));
var end = endCount[i];
var delta = idDelta[i];
for (var codepoint = startCount[i]; codepoint <= end; codepoint++)
{
var glyphId = reader.ReadUInt16BE();
if (glyphId != 0)
{
var glyphIndex = (glyphId + delta) & 0xFFFF;
if (glyphIndex != 0)
{
table.Add((CodePoint)codepoint, glyphIndex);
}
}
}
reader.Seek(currentOffset);
}
else
{
// otherwise, do a straight iteration through the segment
var end = endCount[i];
var delta = idDelta[i];
for (var codepoint = startCount[i]; codepoint <= end; codepoint++)
{
var glyphIndex = (codepoint + delta) & 0xFFFF;
if (glyphIndex != 0)
{
table.Add((CodePoint)codepoint, glyphIndex);
}
}
}
}
return(new CharacterMap(table));
}
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 InvalidFontException("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 InvalidFontException("Unsupported cmap format.");
}
}
public static KerningTable ReadKern(DataReader reader, TableRecord[] tables)
{
// kern table is optional
if (!SfntTables.SeekToTable(reader, tables, FourCC.Kern))
{
return(null);
}
// skip version
reader.Skip(sizeof(short));
// read each subtable and accumulate kerning values
var tableData = new Dictionary <uint, int>();
var subtableCount = reader.ReadUInt16BE();
for (int i = 0; i < subtableCount; i++)
{
// skip version
var currentOffset = reader.Position;
reader.Skip(sizeof(short));
var length = reader.ReadUInt16BE();
var coverage = reader.ReadUInt16BE();
// we (and Windows) only support Format 0 tables
// only care about tables with horizontal kerning data
var kc = (KernCoverage)coverage;
if ((coverage & FormatMask) == 0 && (kc & KernCoverage.Horizontal) != 0 && (kc & KernCoverage.CrossStream) == 0)
{
// read the number of entries; skip over the rest of the header
var entryCount = reader.ReadUInt16BE();
reader.Skip(sizeof(short) * 3);
var isMin = (kc & KernCoverage.Minimum) != 0;
var isOverride = (kc & KernCoverage.Override) != 0;
// read in each entry and accumulate its kerning data
for (int j = 0; j < entryCount; j++)
{
var left = reader.ReadUInt16BE();
var right = reader.ReadUInt16BE();
var value = reader.ReadInt16BE();
// look up the current value, if we have one; if not, start at zero
int current = 0;
var key = ((uint)left << 16) | right;
tableData.TryGetValue(key, out current);
if (isMin)
{
if (current < value)
{
tableData[key] = value;
}
}
else if (isOverride)
{
tableData[key] = value;
}
else
{
tableData[key] = current + value;
}
}
}
// jump to the next subtable
reader.Seek(currentOffset + length);
}
return(new KerningTable(tableData));
}
public static void ReadMaxp(DataReader reader, TableRecord[] tables, ref FaceHeader header)
{
SeekToTable(reader, tables, FourCC.Maxp, required: true);
if (reader.ReadInt32BE() != 0x00010000)
throw new InvalidFontException("Font contains an old style maxp table.");
header.GlyphCount = reader.ReadUInt16BE();
if (header.GlyphCount > MaxGlyphs)
throw new InvalidFontException("Font contains too many glyphs.");
// skip maxPoints, maxContours, maxCompositePoints, maxCompositeContours, maxZones
reader.Skip(sizeof(short) * 5);
header.MaxTwilightPoints = reader.ReadUInt16BE();
header.MaxStorageLocations = reader.ReadUInt16BE();
header.MaxFunctionDefs = reader.ReadUInt16BE();
header.MaxInstructionDefs = reader.ReadUInt16BE();
header.MaxStackSize = reader.ReadUInt16BE();
// sanity checking
if (header.MaxTwilightPoints > MaxTwilightPoints || header.MaxStorageLocations > MaxStorageLocations ||
header.MaxFunctionDefs > MaxFunctionDefs || header.MaxInstructionDefs > MaxFunctionDefs ||
header.MaxStackSize > MaxStackSize)
throw new InvalidFontException("Font programs have limits that are larger than built-in sanity checks.");
}
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 OS2Data ReadOS2(DataReader reader, TableRecord[] tables)
{
SeekToTable(reader, tables, FourCC.OS_2, required: true);
// skip over version, xAvgCharWidth
reader.Skip(sizeof(short) * 2);
var result = new OS2Data
{
Weight = (FontWeight)reader.ReadUInt16BE(),
Stretch = (FontStretch)reader.ReadUInt16BE()
};
// skip over fsType, ySubscriptXSize, ySubscriptYSize, ySubscriptXOffset, ySubscriptYOffset,
// ySuperscriptXSize, ySuperscriptYSize, ySuperscriptXOffset, ySuperscriptXOffset
reader.Skip(sizeof(short) * 9);
result.StrikeoutSize = reader.ReadInt16BE();
result.StrikeoutPosition = reader.ReadInt16BE();
// skip over sFamilyClass, panose[10], ulUnicodeRange1-4, achVendID[4]
reader.Skip(sizeof(short) + sizeof(int) * 4 + 14);
// check various style flags
var fsSelection = (FsSelectionFlags)reader.ReadUInt16BE();
result.Style = (fsSelection & FsSelectionFlags.Italic) != 0 ? FontStyle.Italic :
(fsSelection & FsSelectionFlags.Bold) != 0 ? FontStyle.Bold :
(fsSelection & FsSelectionFlags.Oblique) != 0 ? FontStyle.Oblique :
FontStyle.Regular;
result.IsWWSFont = (fsSelection & FsSelectionFlags.WWS) != 0;
result.UseTypographicMetrics = (fsSelection & FsSelectionFlags.UseTypoMetrics) != 0;
// skip over usFirstCharIndex, usLastCharIndex
reader.Skip(sizeof(short) * 2);
result.TypographicAscender = reader.ReadInt16BE();
result.TypographicDescender = reader.ReadInt16BE();
result.TypographicLineGap = reader.ReadInt16BE();
result.WinAscent = reader.ReadUInt16BE();
result.WinDescent = reader.ReadUInt16BE();
// skip over ulCodePageRange1-2
reader.Skip(sizeof(int) * 2);
result.XHeight = reader.ReadInt16BE();
result.CapHeight = reader.ReadInt16BE();
return result;
}
public static MetricsHeader ReadMetricsHeader(DataReader reader)
{
// skip over version
reader.Skip(sizeof(int));
var header = new MetricsHeader
{
Ascender = reader.ReadInt16BE(),
Descender = reader.ReadInt16BE(),
LineGap = reader.ReadInt16BE()
};
// skip over advanceWidthMax, minLsb, minRsb, xMaxExtent, caretSlopeRise,
// caretSlopeRun, caretOffset, 4 reserved entries, and metricDataFormat
reader.Skip(sizeof(short) * 12);
header.MetricCount = reader.ReadUInt16BE();
return header;
}