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 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 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 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 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 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();
}
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);
}
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 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;
}
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;
}
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 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 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 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 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 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;
}
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;
}
