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 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 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 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;
}
static CompositeGlyph ReadCompositeGlyph(DataReader reader)
{
// we need to keep reading glyphs for as long as
// our flags tell us that there are more to read
var subglyphs = new List<Subglyph>();
CompositeGlyphFlags flags;
do
{
flags = (CompositeGlyphFlags)reader.ReadUInt16BE();
var subglyph = new Subglyph { Flags = flags };
subglyph.Index = reader.ReadUInt16BE();
// read in args; they vary in size based on flags
if ((flags & CompositeGlyphFlags.ArgsAreWords) != 0)
{
subglyph.Arg1 = reader.ReadInt16BE();
subglyph.Arg2 = reader.ReadInt16BE();
}
else
{
subglyph.Arg1 = reader.ReadSByte();
subglyph.Arg2 = reader.ReadSByte();
}
// figure out the transform; we can either have no scale, a uniform
// scale, two independent scales, or a full 2x2 transform matrix
// transform components are in 2.14 fixed point format
var transform = Matrix3x2.Identity;
if ((flags & CompositeGlyphFlags.HaveScale) != 0)
{
var scale = reader.ReadInt16BE() / F2Dot14ToFloat;
transform.M11 = scale;
transform.M22 = scale;
}
else if ((flags & CompositeGlyphFlags.HaveXYScale) != 0)
{
transform.M11 = reader.ReadInt16BE() / F2Dot14ToFloat;
transform.M22 = reader.ReadInt16BE() / F2Dot14ToFloat;
}
else if ((flags & CompositeGlyphFlags.HaveTransform) != 0)
{
transform.M11 = reader.ReadInt16BE() / F2Dot14ToFloat;
transform.M12 = reader.ReadInt16BE() / F2Dot14ToFloat;
transform.M21 = reader.ReadInt16BE() / F2Dot14ToFloat;
transform.M22 = reader.ReadInt16BE() / F2Dot14ToFloat;
}
subglyph.Transform = transform;
subglyphs.Add(subglyph);
} while ((flags & CompositeGlyphFlags.MoreComponents) != 0);
var result = new CompositeGlyph { Subglyphs = subglyphs.ToArray() };
// if we have instructions, read them now
if ((flags & CompositeGlyphFlags.HaveInstructions) != 0)
{
var instructionLength = reader.ReadUInt16BE();
result.Instructions = reader.ReadBytes(instructionLength);
}
return result;
}
static SimpleGlyph ReadSimpleGlyph(DataReader reader, int contourCount)
{
// read contour endpoints
var contours = new int[contourCount];
var lastEndpoint = reader.ReadUInt16BE();
contours[0] = lastEndpoint;
for (int i = 1; i < contours.Length; i++)
{
var endpoint = reader.ReadUInt16BE();
contours[i] = endpoint;
if (contours[i] <= lastEndpoint)
throw new InvalidFontException("Glyph contour endpoints are unordered.");
lastEndpoint = endpoint;
}
// the last contour's endpoint is the number of points in the glyph
var pointCount = lastEndpoint + 1;
var points = new Point[pointCount];
// read instruction data
var instructionLength = reader.ReadUInt16BE();
var instructions = reader.ReadBytes(instructionLength);
// read flags
var flags = new SimpleGlyphFlags[pointCount];
int flagIndex = 0;
while (flagIndex < flags.Length)
{
var f = (SimpleGlyphFlags)reader.ReadByte();
flags[flagIndex++] = f;
// if Repeat is set, this flag data is repeated n more times
if ((f & SimpleGlyphFlags.Repeat) != 0)
{
var count = reader.ReadByte();
for (int i = 0; i < count; i++)
flags[flagIndex++] = f;
}
}
// Read points, first doing all X coordinates and then all Y coordinates.
// The point packing is insane; coords are either 1 byte or 2; they're
// deltas from previous point, and flags let you repeat identical points.
var x = 0;
for (int i = 0; i < points.Length; i++)
{
var f = flags[i];
var delta = 0;
if ((f & SimpleGlyphFlags.ShortX) != 0)
{
delta = reader.ReadByte();
if ((f & SimpleGlyphFlags.SameX) == 0)
delta = -delta;
}
else if ((f & SimpleGlyphFlags.SameX) == 0)
delta = reader.ReadInt16BE();
x += delta;
points[i].X = (FUnit)x;
}
var y = 0;
for (int i = 0; i < points.Length; i++)
{
var f = flags[i];
var delta = 0;
if ((f & SimpleGlyphFlags.ShortY) != 0)
{
delta = reader.ReadByte();
if ((f & SimpleGlyphFlags.SameY) == 0)
delta = -delta;
}
else if ((f & SimpleGlyphFlags.SameY) == 0)
delta = reader.ReadInt16BE();
y += delta;
points[i].Y = (FUnit)y;
points[i].Type = (f & SimpleGlyphFlags.OnCurve) != 0 ? PointType.OnCurve : PointType.Quadratic;
}
return new SimpleGlyph
{
Points = points,
ContourEndpoints = contours,
Instructions = instructions
};
}
public static void ReadGlyph(
DataReader reader, int glyphIndex, int recursionDepth,
BaseGlyph[] glyphTable, uint glyfOffset, uint glyfLength, uint* loca
)
{
// check if this glyph has already been loaded; this can happen
// if we're recursively loading subglyphs as part of a composite
if (glyphTable[glyphIndex] != null)
return;
// prevent bad font data from causing infinite recursion
if (recursionDepth > MaxRecursion)
throw new InvalidFontException("Bad font data; infinite composite recursion.");
// check if this glyph doesn't have any actual data
GlyphHeader header;
var offset = loca[glyphIndex];
if ((glyphIndex < glyphTable.Length - 1 && offset == loca[glyphIndex + 1]) || offset >= glyfLength)
{
// this is an empty glyph, so synthesize a header
header = default(GlyphHeader);
}
else
{
// seek to the right spot and load the header
reader.Seek(glyfOffset + loca[glyphIndex]);
header = new GlyphHeader
{
ContourCount = reader.ReadInt16BE(),
MinX = reader.ReadInt16BE(),
MinY = reader.ReadInt16BE(),
MaxX = reader.ReadInt16BE(),
MaxY = reader.ReadInt16BE()
};
if (header.ContourCount < -1 || header.ContourCount > MaxContours)
throw new InvalidFontException("Invalid number of contours for glyph.");
}
if (header.ContourCount > 0)
{
// positive contours means a simple glyph
glyphTable[glyphIndex] = ReadSimpleGlyph(reader, header.ContourCount);
}
else if (header.ContourCount == -1)
{
// -1 means composite glyph
var composite = ReadCompositeGlyph(reader);
var subglyphs = composite.Subglyphs;
// read each subglyph recrusively
for (int i = 0; i < subglyphs.Length; i++)
ReadGlyph(reader, subglyphs[i].Index, recursionDepth + 1, glyphTable, glyfOffset, glyfLength, loca);
glyphTable[glyphIndex] = composite;
}
else
{
// no data, so synthesize an empty glyph
glyphTable[glyphIndex] = new SimpleGlyph
{
Points = new Point[0],
ContourEndpoints = new int[0]
};
}
// save bounding box
var glyph = glyphTable[glyphIndex];
glyph.MinX = header.MinX;
glyph.MinY = header.MinY;
glyph.MaxX = header.MaxX;
glyph.MaxY = header.MaxY;
}
public static void ReadGlyph(
DataReader reader, int glyphIndex, int recursionDepth,
BaseGlyph[] glyphTable, uint glyfOffset, uint glyfLength, uint *loca
)
{
// check if this glyph has already been loaded; this can happen
// if we're recursively loading subglyphs as part of a composite
if (glyphTable[glyphIndex] != null)
{
return;
}
// prevent bad font data from causing infinite recursion
if (recursionDepth > MaxRecursion)
{
throw new InvalidFontException("Bad font data; infinite composite recursion.");
}
// check if this glyph doesn't have any actual data
GlyphHeader header;
var offset = loca[glyphIndex];
if ((glyphIndex < glyphTable.Length - 1 && offset == loca[glyphIndex + 1]) || offset >= glyfLength)
{
// this is an empty glyph, so synthesize a header
header = default(GlyphHeader);
}
else
{
// seek to the right spot and load the header
reader.Seek(glyfOffset + loca[glyphIndex]);
header = new GlyphHeader {
ContourCount = reader.ReadInt16BE(),
MinX = reader.ReadInt16BE(),
MinY = reader.ReadInt16BE(),
MaxX = reader.ReadInt16BE(),
MaxY = reader.ReadInt16BE()
};
if (header.ContourCount < -1 || header.ContourCount > MaxContours)
{
throw new InvalidFontException("Invalid number of contours for glyph.");
}
}
if (header.ContourCount > 0)
{
// positive contours means a simple glyph
glyphTable[glyphIndex] = ReadSimpleGlyph(reader, header.ContourCount);
}
else if (header.ContourCount == -1)
{
// -1 means composite glyph
var composite = ReadCompositeGlyph(reader);
var subglyphs = composite.Subglyphs;
// read each subglyph recrusively
for (int i = 0; i < subglyphs.Length; i++)
{
ReadGlyph(reader, subglyphs[i].Index, recursionDepth + 1, glyphTable, glyfOffset, glyfLength, loca);
}
glyphTable[glyphIndex] = composite;
}
else
{
// no data, so synthesize an empty glyph
glyphTable[glyphIndex] = new SimpleGlyph {
Points = new Point[0],
ContourEndpoints = new int[0]
};
}
// save bounding box
var glyph = glyphTable[glyphIndex];
glyph.MinX = header.MinX;
glyph.MinY = header.MinY;
glyph.MaxX = header.MaxX;
glyph.MaxY = header.MaxY;
}
public static bool SeekToTable(DataReader reader, TableRecord[] tables, FourCC tag, bool required = false)
{
// check if we have the desired table and that it's not empty
var index = FindTable(tables, tag);
if (index == -1 || tables[index].Length == 0)
{
if (required)
//throw new InvalidFontException($"Missing or empty '{tag}' table.");
throw new InvalidFontException(string.Format(
"Missing or empty '{0}' table.", tag));
return false;
}
// seek to the appropriate offset
reader.Seek(tables[index].Offset);
return true;
}
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 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;
}
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;
}
static SimpleGlyph ReadSimpleGlyph(DataReader reader, int contourCount)
{
// read contour endpoints
var contours = new int[contourCount];
var lastEndpoint = reader.ReadUInt16BE();
contours[0] = lastEndpoint;
for (int i = 1; i < contours.Length; i++)
{
var endpoint = reader.ReadUInt16BE();
contours[i] = endpoint;
if (contours[i] <= lastEndpoint)
{
throw new InvalidFontException("Glyph contour endpoints are unordered.");
}
lastEndpoint = endpoint;
}
// the last contour's endpoint is the number of points in the glyph
var pointCount = lastEndpoint + 1;
var points = new Point[pointCount];
// read instruction data
var instructionLength = reader.ReadUInt16BE();
var instructions = reader.ReadBytes(instructionLength);
// read flags
var flags = new SimpleGlyphFlags[pointCount];
int flagIndex = 0;
while (flagIndex < flags.Length)
{
var f = (SimpleGlyphFlags)reader.ReadByte();
flags[flagIndex++] = f;
// if Repeat is set, this flag data is repeated n more times
if ((f & SimpleGlyphFlags.Repeat) != 0)
{
var count = reader.ReadByte();
for (int i = 0; i < count; i++)
{
flags[flagIndex++] = f;
}
}
}
// Read points, first doing all X coordinates and then all Y coordinates.
// The point packing is insane; coords are either 1 byte or 2; they're
// deltas from previous point, and flags let you repeat identical points.
var x = 0;
for (int i = 0; i < points.Length; i++)
{
var f = flags[i];
var delta = 0;
if ((f & SimpleGlyphFlags.ShortX) != 0)
{
delta = reader.ReadByte();
if ((f & SimpleGlyphFlags.SameX) == 0)
{
delta = -delta;
}
}
else if ((f & SimpleGlyphFlags.SameX) == 0)
{
delta = reader.ReadInt16BE();
}
x += delta;
points[i].X = (FUnit)x;
}
var y = 0;
for (int i = 0; i < points.Length; i++)
{
var f = flags[i];
var delta = 0;
if ((f & SimpleGlyphFlags.ShortY) != 0)
{
delta = reader.ReadByte();
if ((f & SimpleGlyphFlags.SameY) == 0)
{
delta = -delta;
}
}
else if ((f & SimpleGlyphFlags.SameY) == 0)
{
delta = reader.ReadInt16BE();
}
y += delta;
points[i].Y = (FUnit)y;
points[i].Type = (f & SimpleGlyphFlags.OnCurve) != 0 ? PointType.OnCurve : PointType.Quadratic;
}
return(new SimpleGlyph {
Points = points,
ContourEndpoints = contours,
Instructions = instructions
});
}
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 MetricsEntry[] ReadMetricsTable(DataReader reader, int glyphCount, int metricCount)
{
var results = new MetricsEntry[glyphCount];
for (int i = 0; i < metricCount; i++)
{
results[i] = new MetricsEntry
{
Advance = reader.ReadUInt16BE(),
FrontSideBearing = reader.ReadInt16BE()
};
}
// there might be an additional array of fsb-only entries
var extraCount = glyphCount - metricCount;
var lastAdvance = results[metricCount - 1].Advance;
for (int i = 0; i < extraCount; i++)
{
results[i + metricCount] = new MetricsEntry
{
Advance = lastAdvance,
FrontSideBearing = reader.ReadInt16BE()
};
}
return results;
}
static CompositeGlyph ReadCompositeGlyph(DataReader reader)
{
// we need to keep reading glyphs for as long as
// our flags tell us that there are more to read
var subglyphs = new List <Subglyph>();
CompositeGlyphFlags flags;
do
{
flags = (CompositeGlyphFlags)reader.ReadUInt16BE();
var subglyph = new Subglyph {
Flags = flags
};
subglyph.Index = reader.ReadUInt16BE();
// read in args; they vary in size based on flags
if ((flags & CompositeGlyphFlags.ArgsAreWords) != 0)
{
subglyph.Arg1 = reader.ReadInt16BE();
subglyph.Arg2 = reader.ReadInt16BE();
}
else
{
subglyph.Arg1 = reader.ReadSByte();
subglyph.Arg2 = reader.ReadSByte();
}
// figure out the transform; we can either have no scale, a uniform
// scale, two independent scales, or a full 2x2 transform matrix
// transform components are in 2.14 fixed point format
var transform = Matrix3x2.Identity;
if ((flags & CompositeGlyphFlags.HaveScale) != 0)
{
var scale = reader.ReadInt16BE() / F2Dot14ToFloat;
transform.M11 = scale;
transform.M22 = scale;
}
else if ((flags & CompositeGlyphFlags.HaveXYScale) != 0)
{
transform.M11 = reader.ReadInt16BE() / F2Dot14ToFloat;
transform.M22 = reader.ReadInt16BE() / F2Dot14ToFloat;
}
else if ((flags & CompositeGlyphFlags.HaveTransform) != 0)
{
transform.M11 = reader.ReadInt16BE() / F2Dot14ToFloat;
transform.M12 = reader.ReadInt16BE() / F2Dot14ToFloat;
transform.M21 = reader.ReadInt16BE() / F2Dot14ToFloat;
transform.M22 = reader.ReadInt16BE() / F2Dot14ToFloat;
}
subglyph.Transform = transform;
subglyphs.Add(subglyph);
} while ((flags & CompositeGlyphFlags.MoreComponents) != 0);
var result = new CompositeGlyph {
Subglyphs = subglyphs.ToArray()
};
// if we have instructions, read them now
if ((flags & CompositeGlyphFlags.HaveInstructions) != 0)
{
var instructionLength = reader.ReadUInt16BE();
result.Instructions = reader.ReadBytes(instructionLength);
}
return(result);
}
static string ExtractString(DataReader reader, uint baseOffset, StringData data)
{
reader.Seek(baseOffset + data.Offset);
var bytes = reader.ReadBytes(data.Length);
return Encoding.BigEndianUnicode.GetString(bytes);
}
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 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();
}
}
/// <summary>
/// Initializes a new instance of the <see cref="FontFace"/> class.
/// </summary>
/// <param name="stream">A stream pointing to the font file.</param>
/// <remarks>
/// All relevant font data is loaded into memory and retained by the FontFace object.
/// Once the constructor finishes you are free to close the stream.
/// </remarks>
public FontFace(Stream stream)
{
// read the face header and table records
using (var reader = new DataReader(stream))
{
var tables = SfntTables.ReadFaceHeader(reader);
// read head and maxp tables for font metadata and limits
FaceHeader head;
SfntTables.ReadHead(reader, tables, out head);
SfntTables.ReadMaxp(reader, tables, ref head);
unitsPerEm = head.UnitsPerEm;
integerPpems = (head.Flags & HeadFlags.IntegerPpem) != 0;
// horizontal metrics header and data
SfntTables.SeekToTable(reader, tables, FourCC.Hhea, required: true);
var hMetricsHeader = SfntTables.ReadMetricsHeader(reader);
SfntTables.SeekToTable(reader, tables, FourCC.Hmtx, required: true);
hmetrics = SfntTables.ReadMetricsTable(reader, head.GlyphCount, hMetricsHeader.MetricCount);
// font might optionally have vertical metrics
if (SfntTables.SeekToTable(reader, tables, FourCC.Vhea))
{
var vMetricsHeader = SfntTables.ReadMetricsHeader(reader);
SfntTables.SeekToTable(reader, tables, FourCC.Vmtx, required: true);
vmetrics = SfntTables.ReadMetricsTable(reader, head.GlyphCount, vMetricsHeader.MetricCount);
}
// OS/2 table has even more metrics
var os2Data = SfntTables.ReadOS2(reader, tables);
xHeight = os2Data.XHeight;
capHeight = os2Data.CapHeight;
Weight = os2Data.Weight;
Stretch = os2Data.Stretch;
Style = os2Data.Style;
// optional PostScript table has random junk in it
SfntTables.ReadPost(reader, tables, ref head);
IsFixedWidth = head.IsFixedPitch;
// read character-to-glyph mapping tables and kerning table
charMap = CharacterMap.ReadCmap(reader, tables);
kernTable = KerningTable.ReadKern(reader, tables);
// name data
var names = SfntTables.ReadNames(reader, tables);
Family = names.TypographicFamilyName ?? names.FamilyName;
Subfamily = names.TypographicSubfamilyName ?? names.SubfamilyName;
FullName = names.FullName;
UniqueID = names.UniqueID;
Version = names.Version;
Description = names.Description;
// load glyphs if we have them
if (SfntTables.SeekToTable(reader, tables, FourCC.Glyf))
{
unsafe
{
// read in the loca table, which tells us the byte offset of each glyph
var loca = stackalloc uint[head.GlyphCount];
SfntTables.ReadLoca(reader, tables, head.IndexFormat, loca, head.GlyphCount);
// we need to know the length of the glyf table because of some weirdness in the loca table:
// if a glyph is "missing" (like a space character), then its loca[n] entry is equal to loca[n+1]
// if the last glyph in the set is missing, then loca[n] == glyf table length
SfntTables.SeekToTable(reader, tables, FourCC.Glyf);
var glyfOffset = reader.Position;
var glyfLength = tables[SfntTables.FindTable(tables, FourCC.Glyf)].Length;
// read in all glyphs
glyphs = new BaseGlyph[head.GlyphCount];
for (int i = 0; i < glyphs.Length; i++)
SfntTables.ReadGlyph(reader, i, 0, glyphs, glyfOffset, glyfLength, loca);
}
}
// embedded bitmaps
SbitTable.Read(reader, tables);
// metrics calculations: if the UseTypographicMetrics flag is set, then
// we should use the sTypo*** data for line height calculation
if (os2Data.UseTypographicMetrics)
{
// include the line gap in the ascent so that
// white space is distributed above the line
cellAscent = os2Data.TypographicAscender + os2Data.TypographicLineGap;
cellDescent = -os2Data.TypographicDescender;
lineHeight = os2Data.TypographicAscender + os2Data.TypographicLineGap - os2Data.TypographicDescender;
}
else
{
// otherwise, we need to guess at whether hhea data or os/2 data has better line spacing
// this is the recommended procedure based on the OS/2 spec extra notes
cellAscent = os2Data.WinAscent;
cellDescent = Math.Abs(os2Data.WinDescent);
lineHeight = Math.Max(
Math.Max(0, hMetricsHeader.LineGap) + hMetricsHeader.Ascender + Math.Abs(hMetricsHeader.Descender),
cellAscent + cellDescent
);
}
// give sane defaults for underline and strikeout data if missing
underlineSize = head.UnderlineThickness != 0 ?
head.UnderlineThickness : (head.UnitsPerEm + 7) / 14;
underlinePosition = head.UnderlinePosition != 0 ?
head.UnderlinePosition : -((head.UnitsPerEm + 5) / 10);
strikeoutSize = os2Data.StrikeoutSize != 0 ?
os2Data.StrikeoutSize : underlineSize;
strikeoutPosition = os2Data.StrikeoutPosition != 0 ?
os2Data.StrikeoutPosition : head.UnitsPerEm / 3;
// create some vertical metrics in case we haven't loaded any
verticalSynthesized = new MetricsEntry
{
FrontSideBearing = os2Data.TypographicAscender,
Advance = os2Data.TypographicAscender - os2Data.TypographicDescender
};
// read in global font program data
controlValueTable = SfntTables.ReadCvt(reader, tables);
prepProgram = SfntTables.ReadProgram(reader, tables, FourCC.Prep);
interpreter = new Interpreter(
head.MaxStackSize,
head.MaxStorageLocations,
head.MaxFunctionDefs,
head.MaxInstructionDefs,
head.MaxTwilightPoints
);
// the fpgm table optionally contains a program to run at initialization time
var fpgm = SfntTables.ReadProgram(reader, tables, FourCC.Fpgm);
if (fpgm != null)
interpreter.InitializeFunctionDefs(fpgm);
}
Id = Interlocked.Increment(ref currentId);
}
public unsafe static NameData ReadNames(DataReader reader, TableRecord[] tables)
{
if (!SeekToTable(reader, tables, FourCC.Name))
return default(NameData);
// read header
var currentOffset = reader.Position;
var format = reader.ReadUInt16BE();
var count = reader.ReadUInt16BE();
var dataOffset = currentOffset + reader.ReadUInt16BE();
// read name records, filtering out non-Unicode and platforms we don't know about
var stringData = stackalloc StringData[count];
var stringDataCount = 0;
for (int i = 0; i < count; i++)
{
var platform = reader.ReadUInt16BE();
var encoding = reader.ReadUInt16BE();
var language = reader.ReadUInt16BE();
var name = reader.ReadUInt16BE();
var length = reader.ReadUInt16BE();
var offset = reader.ReadUInt16BE();
// we only support Unicode strings
if (platform == PlatformID.Microsoft)
{
if (encoding != WindowsEncoding.UnicodeBmp && encoding != WindowsEncoding.UnicodeFull)
continue;
if (language != CultureInfo.CurrentCulture.LCID)
continue;
}
else if (platform != PlatformID.Unicode)
continue;
stringData[stringDataCount++] = new StringData
{
Name = name,
Offset = offset,
Length = length
};
}
// find strings we care about and extract them from the blob
var nameData = new NameData();
for (int i = 0; i < stringDataCount; i++)
{
var data = stringData[i];
switch (data.Name)
{
case NameID.FamilyName: nameData.FamilyName = ExtractString(reader, dataOffset, data); break;
case NameID.SubfamilyName: nameData.SubfamilyName = ExtractString(reader, dataOffset, data); break;
case NameID.UniqueID: nameData.UniqueID = ExtractString(reader, dataOffset, data); break;
case NameID.FullName: nameData.FullName = ExtractString(reader, dataOffset, data); break;
case NameID.Version: nameData.Version = ExtractString(reader, dataOffset, data); break;
case NameID.Description: nameData.Description = ExtractString(reader, dataOffset, data); break;
case NameID.TypographicFamilyName: nameData.TypographicFamilyName = ExtractString(reader, dataOffset, data); break;
case NameID.TypographicSubfamilyName: nameData.TypographicSubfamilyName = ExtractString(reader, dataOffset, data); break;
}
}
return nameData;
}
public static FUnit[] ReadCvt(DataReader reader, TableRecord[] tables)
{
var index = FindTable(tables, FourCC.Cvt);
if (index == -1)
return null;
reader.Seek(tables[index].Offset);
var results = new FUnit[tables[index].Length / sizeof(short)];
for (int i = 0; i < results.Length; i++)
results[i] = (FUnit)reader.ReadInt16BE();
return results;
}
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 byte[] ReadProgram(DataReader reader, TableRecord[] tables, FourCC tag)
{
var index = FindTable(tables, tag);
if (index == -1)
return null;
reader.Seek(tables[index].Offset);
return reader.ReadBytes((int)tables[index].Length);
}
static Metadata LoadMetadata (Stream stream) {
using (var reader = new DataReader(stream)) {
var tables = SfntTables.ReadFaceHeader(reader);
var names = SfntTables.ReadNames(reader, tables);
var os2Data = SfntTables.ReadOS2(reader, tables);
return new Metadata {
Family = names.TypographicFamilyName ?? names.FamilyName,
Weight = os2Data.Weight,
Stretch = os2Data.Stretch,
Style = os2Data.Style
};
}
}
public unsafe static NameData ReadNames(DataReader reader, TableRecord[] tables)
{
if (!SeekToTable(reader, tables, FourCC.Name))
{
return(default(NameData));
}
// read header
var currentOffset = reader.Position;
var format = reader.ReadUInt16BE();
var count = reader.ReadUInt16BE();
var dataOffset = currentOffset + reader.ReadUInt16BE();
// read name records, filtering out non-Unicode and platforms we don't know about
var stringData = stackalloc StringData[count];
var stringDataCount = 0;
for (int i = 0; i < count; i++)
{
var platform = reader.ReadUInt16BE();
var encoding = reader.ReadUInt16BE();
var language = reader.ReadUInt16BE();
var name = reader.ReadUInt16BE();
var length = reader.ReadUInt16BE();
var offset = reader.ReadUInt16BE();
// we only support Unicode strings
if (platform == PlatformID.Microsoft)
{
if (encoding != WindowsEncoding.UnicodeBmp && encoding != WindowsEncoding.UnicodeFull)
{
continue;
}
if (language != CultureInfo.CurrentCulture.LCID)
{
continue;
}
}
else if (platform != PlatformID.Unicode)
{
continue;
}
stringData[stringDataCount++] = new StringData {
Name = name,
Offset = offset,
Length = length
};
}
// find strings we care about and extract them from the blob
var nameData = new NameData();
for (int i = 0; i < stringDataCount; i++)
{
var data = stringData[i];
switch (data.Name)
{
case NameID.FamilyName: nameData.FamilyName = ExtractString(reader, dataOffset, data); break;
case NameID.SubfamilyName: nameData.SubfamilyName = ExtractString(reader, dataOffset, data); break;
case NameID.UniqueID: nameData.UniqueID = ExtractString(reader, dataOffset, data); break;
case NameID.FullName: nameData.FullName = ExtractString(reader, dataOffset, data); break;
case NameID.Version: nameData.Version = ExtractString(reader, dataOffset, data); break;
case NameID.Description: nameData.Description = ExtractString(reader, dataOffset, data); break;
case NameID.TypographicFamilyName: nameData.TypographicFamilyName = ExtractString(reader, dataOffset, data); break;
case NameID.TypographicSubfamilyName: nameData.TypographicSubfamilyName = ExtractString(reader, dataOffset, data); break;
}
}
return(nameData);
}
