/// <summary>
/// Read the header table from the data stream.
/// </summary>
public static HeaderTable Load(TrueTypeDataBytes data, TrueTypeHeaderTable table)
{
data.Seek(table.Offset);
var version = data.Read32Fixed();
var fontRevision = data.Read32Fixed();
var checkSumAdjustment = data.ReadUnsignedInt();
var magicNumber = data.ReadUnsignedInt();
if (magicNumber != 0x5F0F3CF5)
{
throw new InvalidOperationException("The magic number for this TrueType font was incorrect. Value was: " + magicNumber);
}
var flags = data.ReadUnsignedShort();
var unitsPerEm = data.ReadUnsignedShort();
if (unitsPerEm < 16 || unitsPerEm > 16384)
{
throw new InvalidOperationException($"The units per em for this TrueType font was incorrect, value should be between 16 and 16384 but found {unitsPerEm} istead.");
}
DateTime created;
try
{
created = data.ReadInternationalDate();
}
catch (InvalidFontFormatException)
{
created = DateTime.MinValue;
}
DateTime modified;
try
{
modified = data.ReadInternationalDate();
}
catch (InvalidFontFormatException)
{
modified = DateTime.MinValue;
}
var xMin = data.ReadSignedShort();
var yMin = data.ReadSignedShort();
var xMax = data.ReadSignedShort();
var yMax = data.ReadSignedShort();
var macStyle = data.ReadUnsignedShort();
var lowestRecPpem = data.ReadUnsignedShort();
var fontDirectionHint = data.ReadSignedShort();
var indexToLocFormat = (IndexToLocationTable.EntryFormat)data.ReadSignedShort();
var glyphDataFormat = data.ReadSignedShort();
return(new HeaderTable(table, version, fontRevision, checkSumAdjustment,
magicNumber, flags, unitsPerEm, created, modified,
xMin, yMin, xMax, yMax, macStyle, lowestRecPpem,
fontDirectionHint, indexToLocFormat, glyphDataFormat));
}