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.TypographicFamily,
familyNames.Value.TypographicSubfamily == string.Empty ? null : familyNames.Value.TypographicSubfamily,
familyNames.Value.FontName,
os2Info.Value.Weight,
(os2Info.Value.Style & FontStyle.Bold) != 0,
(os2Info.Value.Style & FontStyle.Italic) != 0,
(os2Info.Value.Style & FontStyle.Oblique) != 0,
(os2Info.Value.Style & FontStyle.Underscore) != 0,
(os2Info.Value.Style & FontStyle.Negative) != 0,
(os2Info.Value.Style & FontStyle.Outlined) != 0,
(os2Info.Value.Style & FontStyle.Strikeout) != 0,
(os2Info.Value.Style & FontStyle.Regular) != 0,
filename
));
}
// http://www.microsoft.com/typography/otspec/name.htm
private static FamilyNamesInfo ReadFamilyNames(BigEndianBinaryReader br, uint offset)
{
br.BaseStream.Seek(offset, SeekOrigin.Begin);
var fSelector = br.ReadUInt16();
var numNameRecords = br.ReadUInt16();
var storageOffset = br.ReadUInt16();
var fontFamilyName = (string)null;
var fontSubfamilyName = (string)null;
var typographicFamilyName = (string)null;
var typographicSubfamilyName = (string)null;
for (var ri = 0; ri < numNameRecords; ri++)
{
var platformId = (PlatformId)br.ReadUInt16();
var encodingId = br.ReadUInt16();
var languageId = br.ReadUInt16();
var nameId = (NameId)br.ReadUInt16();
var stringLength = br.ReadUInt16();
var stringOffset = br.ReadUInt16();
// Assume we are on Windows
switch (platformId)
{
case PlatformId.Unicode:
break;
case PlatformId.Windows:
// We only want en-US
if (languageId != 1033)
{
continue;
}
break;
default:
continue;
}
switch (nameId)
{
case NameId.TypographicFamilyName:
case NameId.TypographicSubfamilyName:
case NameId.FontFamilyName:
case NameId.FontSubfamilyName:
break;
default:
// Don't bother reading other strings
continue;
}
var position = br.BaseStream.Position;
br.BaseStream.Seek(offset + storageOffset + stringOffset, SeekOrigin.Begin);
var str = Encoding.BigEndianUnicode.GetString(br.ReadBytes(stringLength));
br.BaseStream.Seek(position, SeekOrigin.Begin);
switch (nameId)
{
case NameId.TypographicFamilyName:
typographicFamilyName = str;
break;
case NameId.TypographicSubfamilyName:
typographicSubfamilyName = str;
break;
case NameId.FontFamilyName:
fontFamilyName = str;
break;
case NameId.FontSubfamilyName:
fontSubfamilyName = str;
break;
}
}
return(typographicFamilyName == null
? new FamilyNamesInfo(fontFamilyName, fontSubfamilyName, fontFamilyName)
: new FamilyNamesInfo(typographicFamilyName, typographicSubfamilyName, fontFamilyName));
}
