/// <summary>
/// Reads the contents of the "kern" table from the current position
/// in the supplied stream.
/// </summary>
/// <param name="reader"></param>
protected internal override void Read(FontFileReader reader)
{
FontFileStream stream = reader.Stream;
// Skip version field
stream.Skip(PrimitiveSizes.UShort);
// Number of subtables
int numTables = stream.ReadUShort();
for (int i = 0; i < numTables; i++)
{
// Another pesky version field
stream.Skip(PrimitiveSizes.UShort);
// Length of the subtable, in bytes (including header).
ushort length = stream.ReadUShort();
// Type of information is contained in this table.
ushort coverage = stream.ReadUShort();
// Only interested in horiztonal kerning values in format 0
if ((coverage & HoriztonalMask) == 1 &&
(coverage & MinimumMask) == 0 &&
((coverage >> 8) == 0))
{
// The number of kerning pairs in the table.
int numPairs = stream.ReadUShort();
hasKerningInfo = true;
pairs = new KerningPairs(numPairs);
// Skip pointless shit
stream.Skip(3 * PrimitiveSizes.UShort);
for (int j = 0; j < numPairs; j++)
{
pairs.Add(
stream.ReadUShort(), // Left glyph index
stream.ReadUShort(), // Right glyph index
stream.ReadFWord()); // Kerning amount
}
}
else
{
stream.Skip(length - 3 * PrimitiveSizes.UShort);
}
}
}
/// <summary>
/// Reads the Offset and Directory tables. If the FontFileStream represents
/// a TrueType collection, this method will look for the aforementioned
/// tables belonging to <i>fontName</i>.
/// </summary>
/// <remarks>
/// This method can handle a TrueType collection.
/// </remarks>
protected void ReadTableHeaders()
{
// Check for possible TrueType collection
string tag = Encoding.ASCII.GetString(stream.ReadTag());
if (tag == TableNames.Ttcf)
{
// Skip Version field - will be either 1.0 or 2.0
stream.Skip(PrimitiveSizes.ULong);
// Number of fonts in TrueType collection
int numFonts = (int)stream.ReadULong();
bool foundFont = false;
for (int i = 0; i < numFonts && !foundFont; i++)
{
// Offset from beginning of file to a font's subtable
uint directoryOffset = stream.ReadULong();
// Set a restore point since the code below will alter the stream position
stream.SetRestorePoint();
stream.Position = directoryOffset;
header = new TrueTypeHeader();
header.Read(stream);
// To ascertain whether this font is the one we're looking for,
// we must read the 'name' table.
if (!header.Contains(TableNames.Name))
{
throw new Exception("Unable to parse TrueType collection - missing 'head' table.");
}
// If font name is not supplied, select the first font in the colleciton;
// otherwise must have an exact match
NameTable nameTable = (NameTable)GetTable(TableNames.Name);
if (fontName == String.Empty || nameTable.FullName == fontName)
{
foundFont = true;
}
// Stream will now point to the next directory offset
stream.Restore();
}
// We were unable to locate font in collection
if (!foundFont)
{
throw new Exception("Unable to locate font '" + fontName + "' in TrueType collection");
}
}
else
{
stream.Position = 0;
// Read Offset and Directory tables
header = new TrueTypeHeader();
header.Read(stream);
}
}
private void WriteTableDirectory()
{
stream.SetRestorePoint();
stream.Position = 0;
stream.Skip(OffsetTableSize);
foreach (FontTable table in tables.Values)
{
stream.WriteULong(table.Tag);
stream.WriteULong(table.Entry.CheckSum);
stream.WriteULong(table.Entry.Offset);
stream.WriteULong(table.Entry.Length);
}
stream.Restore();
}
protected internal void Read(FontFileStream stream) {
// Skip sfnt version (0x00010000 for version 1.0).
stream.Skip(PrimitiveSizes.Fixed);
// Number of tables
int numTables = stream.ReadUShort();
// Skip searchRange, entrySelector and rangeShift entries (3 x ushort)
stream.Skip(PrimitiveSizes.UShort*3);
directoryEntries = new Hashtable(numTables);
for (int i = 0; i < numTables; i++) {
DirectoryEntry entry = new DirectoryEntry(
stream.ReadTag(), // 4-byte identifier.
stream.ReadULong(), // CheckSum for this table.
stream.ReadULong(), // Offset from beginning of TrueType font file.
stream.ReadULong() // Length of this table.
);
directoryEntries.Add(entry.TableName, entry);
}
}
protected internal void Read(FontFileStream stream)
{
// Skip sfnt version (0x00010000 for version 1.0).
stream.Skip(PrimitiveSizes.Fixed);
// Number of tables
int numTables = stream.ReadUShort();
// Skip searchRange, entrySelector and rangeShift entries (3 x ushort)
stream.Skip(PrimitiveSizes.UShort * 3);
directoryEntries = new Hashtable(numTables);
for (int i = 0; i < numTables; i++)
{
DirectoryEntry entry = new DirectoryEntry(
stream.ReadTag(), // 4-byte identifier.
stream.ReadULong(), // CheckSum for this table.
stream.ReadULong(), // Offset from beginning of TrueType font file.
stream.ReadULong() // Length of this table.
);
directoryEntries.Add(entry.TableName, entry);
}
}
