private static TypographicFont ParseOpenTypeStream(BigEndianBinaryReader br, long streamOffset, string filename)
{
br.BaseStream.Seek(streamOffset, SeekOrigin.Begin);
// This version check is crucial, since there is no tag at the beginning of the stream.
// If it doesn't match either of the known spec version IDs, it's probably a FON file which we don't parse.
var version = br.ReadUInt32();
const uint trueTypeOutlinesVersion = 0x00010000;
const uint ccfVersion = 0x4F54544F; // "OTTO"
if (version != trueTypeOutlinesVersion && version != ccfVersion)
{
return(null);
}
var numTables = br.ReadUInt16();
var searchRange = br.ReadUInt16();
var entrySelector = br.ReadUInt16();
var rangeShift = br.ReadUInt16();
var familyNames = default(FamilyNamesInfo?);
var os2Info = default(OS2Info?);
for (var ti = 0; ti < numTables; ti++)
{
var tag = Encoding.ASCII.GetString(br.ReadBytes(4));
var checksum = br.ReadUInt32();
var offset = br.ReadUInt32();
var length = br.ReadUInt32();
var position = br.BaseStream.Position;
switch (tag)
{
case "name":
familyNames = ReadFamilyNames(br, offset);
break;
case "OS/2":
os2Info = ReadOS2(br, offset);
break;
}
if (familyNames != null && os2Info != null)
{
break;
}
br.BaseStream.Seek(position, SeekOrigin.Begin);
}
if (familyNames == null || os2Info == null)
{
return(null);
}
return(new TypographicFont(familyNames.Value, os2Info.Value, filename));
}
public static TypographicFont[] Read(string filename)
{
// Do not check the file extension. Files are often misnamed. Detect by contents.
using (var file = new FileStream(filename, FileMode.Open, FileAccess.Read))
using (var br = new BigEndianBinaryReader(file))
{
if (Encoding.ASCII.GetString(br.ReadBytes(4)) == "ttcf")
{
// Font collection detected.
// This check is probably not necessary, since future versions are probably going to be back-compatible
var version = br.ReadUInt32();
// const uint knownVersion1 = 0x00010000, knownVersion2 = 0x00020000;
// if (version != knownVersion1 && version != knownVersion2) return new TypographicFont[0];
var numContainedFonts = br.ReadUInt32();
var fontStreamOffsets = new uint[numContainedFonts];
for (var fi = 0; fi < fontStreamOffsets.Length; fi++)
{
fontStreamOffsets[fi] = br.ReadUInt32();
}
var r = new List <TypographicFont>();
for (var fi = 0; fi < fontStreamOffsets.Length; fi++)
{
var font = ParseOpenTypeStream(br, fontStreamOffsets[fi], filename);
if (font != null)
{
r.Add(font);
}
}
return(r.ToArray());
}
else
{
// No collection detected, assume this is an OpenType stream.
var font = ParseOpenTypeStream(br, 0, filename);
return(font == null ? new TypographicFont[0] : new[] { font });
}
}
}
