public Glyph GetGlyphData(ushort glyphId)
{
if (GlyphCache.ContainsKey(glyphId))
{
return(GlyphCache[glyphId]);
}
var dataOffset = font.loca.Offsets[glyphId];
var reader = new TrueTypeReader(Data);
reader.Seek(dataOffset);
var glyph = new Glyph()
{
NumberOfContours = reader.ReadShort(),
XMin = reader.ReadFWord(),
YMin = reader.ReadFWord(),
XMax = reader.ReadFWord(),
YMax = reader.ReadFWord()
};
reader.Dispose();
GlyphCache[glyphId] = glyph;
return(glyph);
}
public override void Process(TrueTypeFont font)
{
var reader = new TrueTypeReader(Data);
Version = reader.ReadUShort();
EncodingTableCount = reader.ReadUShort();
EncodingTables = new List <EncodingTableEntry>(EncodingTableCount);
for (var i = 0; i < EncodingTableCount; i++)
{
EncodingTables.Add(new EncodingTableEntry()
{
Platform = (Platform)reader.ReadUShort(),
Encoding = (Encoding)reader.ReadUShort(),
Offset = reader.ReadULong()
});
}
foreach (var encodingTable in EncodingTables)
{
reader.Seek(encodingTable.Offset);
var format = (CmapSubtableType)reader.ReadUShort();
var length = reader.ReadUShort();
var subtableProcessorType = ImplementationTypeAttribute.GetTypeFromEnumValue(typeof(CmapSubtableType), format);
if (subtableProcessorType == null)
{
continue;
}
var subtableProcessor = Activator.CreateInstance(subtableProcessorType) as CharacterToGlyphSubtableBase;
subtableProcessor.EncodingTableEntry = encodingTable;
subtableProcessor.ReadData(reader, encodingTable.Offset, length);
Subtables.Add(subtableProcessor);
}
ProcessSubtables(font);
reader.Dispose();
}
public override void ReadData(TrueTypeReader reader, uint offset, uint length)
{
// This weirdness is because some fonts have a malformed subtable header that lists the length incorrectly.
// The actual length can be calculated by peaking the number of kern pairs, and calculating it back.
reader.Seek(offset);
var version = reader.ReadUShort();
var len = reader.ReadUShort();
var coverage = reader.ReadUShort();
var numberOfPairs = reader.ReadUShort();
var kernpairLength = numberOfPairs * BytesPerKernpair;
var calculatedLength = kernpairLength + BytesInHeader;
if (calculatedLength != len)
{
Debug.WriteLine("ERROR: Detected kern subtable length does not match specified value. Using detected value.");
}
base.ReadData(reader, offset, (uint)calculatedLength);
}
public override ushort GetGlyphId(ushort charCode)
{
ushort glyphId = 0;
/// You search for the first endCode that is greater than or equal to the character code you want to map.
/// If the corresponding startCode is less than or equal to the character code, then you use the corresponding
/// idDelta and idRangeOffset to map the character code to a glyph index (otherwise, the missingGlyph is returned).
ushort endCode = 0;
int segment = 0;
while (true)
{
endCode = EndCounts[segment];
if (endCode >= charCode)
{
break;
}
else
{
segment++;
}
}
var startCode = StartCounts[segment];
if (startCode <= charCode)
{
// use idDelta and idRangeOffset to map charcode to glyphindex
var idDelta = IdDeltas[segment];
var idRangeOffset = IdRangeOffsets[segment];
if (idRangeOffset == 0)
{
unchecked
{
glyphId = (ushort)(idDelta + charCode);
}
}
else
{
// use glyphIds data
var idStreamPosition = idRangeOffset + 2 * (charCode - startCode) + IdRangeOffsetPositions[segment];
ushort readGlyphValue;
using (var reader = new TrueTypeReader(base.Data))
{
reader.Seek(idStreamPosition);
readGlyphValue = reader.ReadUShort();
}
if (readGlyphValue != 0)
{
unchecked
{
glyphId = (ushort)(idDelta + readGlyphValue);
}
}
}
}
return(glyphId);
}
