private static TrueTypeFont ParseTables(decimal version, IReadOnlyDictionary <string, TrueTypeHeaderTable> tables, TrueTypeDataBytes data)
{
var isPostScript = tables.ContainsKey(TrueTypeHeaderTable.Cff);
var tableRegister = new TableRegister();
if (!tables.TryGetValue(TrueTypeHeaderTable.Head, out var table))
{
throw new InvalidOperationException($"The {TrueTypeHeaderTable.Head} table is required.");
}
// head
tableRegister.HeaderTable = HeaderTable.Load(data, table);
if (!tables.TryGetValue(TrueTypeHeaderTable.Hhea, out var hHead))
{
throw new InvalidOperationException("The horizontal header table is required.");
}
// hhea
tableRegister.HorizontalHeaderTable = HorizontalHeaderTable.Load(data, hHead);
if (!tables.TryGetValue(TrueTypeHeaderTable.Maxp, out var maxHeaderTable))
{
throw new InvalidOperationException("The maximum profile table is required.");
}
// maxp
tableRegister.MaximumProfileTable = BasicMaximumProfileTable.Load(data, maxHeaderTable);
// post
if (tables.TryGetValue(TrueTypeHeaderTable.Post, out var postscriptHeaderTable))
{
tableRegister.PostScriptTable = PostScriptTable.Load(data, postscriptHeaderTable, tableRegister.MaximumProfileTable);
}
if (!isPostScript)
{
if (!tables.TryGetValue(TrueTypeHeaderTable.Loca, out var indexToLocationHeaderTable))
{
throw new InvalidOperationException("The location to index table is required for non-PostScript fonts.");
}
// loca
tableRegister.IndexToLocationTable =
IndexToLocationTable.Load(data, indexToLocationHeaderTable, tableRegister);
if (!tables.TryGetValue(TrueTypeHeaderTable.Glyf, out var glyphHeaderTable))
{
throw new InvalidOperationException("The glyph table is required for non-PostScript fonts.");
}
// glyf
tableRegister.GlyphDataTable = GlyphDataTable.Load(data, glyphHeaderTable, tableRegister);
OptionallyParseTables(tables, data, tableRegister);
}
return(new TrueTypeFont(version, tables, tableRegister));
}
public static Font ReadFromStream(Stream stream)
{
var font = new Font();
var reader = new BinaryReader(stream);
// Offset Table
font.OffsetTable = OffsetTable.Read(reader);
// Head
var headTableRecord = font.OffsetTable.TableRecords.Single(x => x.TableTag == HeadTable.Tag);
stream.Seek(headTableRecord.Offset, SeekOrigin.Begin);
font.HeadTable = HeadTable.Read(reader);
// Horizontal Header
var horizontalHeaderTableRecord = font.OffsetTable.TableRecords.Single(x => x.TableTag == HorizontalHeaderTable.Tag);
stream.Seek(horizontalHeaderTableRecord.Offset, SeekOrigin.Begin);
font.HorizontalHeaderTable = HorizontalHeaderTable.Read(reader);
// Maximum Profile
var maximumProfileTableRecord = font.OffsetTable.TableRecords.Single(x => x.TableTag == MaximumProfileTableBase.Tag);
stream.Seek(maximumProfileTableRecord.Offset, SeekOrigin.Begin);
var maximumProfileTableVersion = Math.Round(reader.ReadFixedPointNumber(), 2);
if (maximumProfileTableVersion == 0.5m)
{
font.MaximumProfileTable = MaximumProfileTableV0_5.Read(reader, maximumProfileTableVersion);
}
else if (maximumProfileTableVersion == 1.0m)
{
font.MaximumProfileTable = MaximumProfileTableV1.Read(reader, maximumProfileTableVersion);
}
// Horizontal Metrics
var horizontalMetricsTableRecord = font.OffsetTable.TableRecords.Single(x => x.TableTag == HorizontalMetricsTable.Tag);
stream.Seek(horizontalMetricsTableRecord.Offset, SeekOrigin.Begin);
font.HorizontalMetricsTable = HorizontalMetricsTable.Read(reader,
font.HorizontalHeaderTable.NumberOfHMetrics,
font.MaximumProfileTable.NumGlyphs);
// Glyph
var glyphTableRecord = font.OffsetTable.TableRecords.Single(x => x.TableTag == GlyphTable.Tag);
font.GlyphTable = new GlyphTable(reader, glyphTableRecord.Offset);
// IndexLocation
var indexLocationTableRecord = font.OffsetTable.TableRecords.Single(x => x.TableTag == IndexLocationTableBase.Tag);
stream.Seek(indexLocationTableRecord.Offset, SeekOrigin.Begin);
if (font.HeadTable.IndexToLocFormat == 0)
{
font.IndexLocationTable = IndexLocationShortFormatTable.Read(reader, font.MaximumProfileTable.NumGlyphs);
}
else
{
font.IndexLocationTable = IndexLocationLongFormatTable.Read(reader, font.MaximumProfileTable.NumGlyphs);
}
// PostScript
var postScriptTableRecord = font.OffsetTable.TableRecords.Single(x => x.TableTag == PostScriptTable.Tag);
stream.Seek(postScriptTableRecord.Offset, SeekOrigin.Begin);
font.PostScriptTable = PostScriptTable.Read(reader);
// OS/2 and Windows
var os2TableRecord = font.OffsetTable.TableRecords.Single(x => x.TableTag == Os2Table.Tag);
stream.Seek(os2TableRecord.Offset, SeekOrigin.Begin);
font.Os2Table = Os2Table.Read(reader);
// CharacterMap
var characterMapTableRecord = font.OffsetTable.TableRecords.Single(x => x.TableTag == CharacterMapTable.Tag);
stream.Seek(characterMapTableRecord.Offset, SeekOrigin.Begin);
font.CharacterMapTable = CharacterMapTable.Read(reader);
return(font);
}
/**
* Creates a new font descriptor dictionary for the given TTF.
*/
private FontDescriptor CreateFontDescriptor(TrueTypeFont ttf)
{
FontDescriptor fd = new FontDescriptor(document, new PdfDictionary());
fd.FontName = ttf.Name;
OS2WindowsMetricsTable os2 = ttf.OS2Windows;
PostScriptTable post = ttf.PostScript;
// Flags
var flags = (FlagsEnum)0;
flags |= (post.IsFixedPitch > 0 || ttf.HorizontalHeader.NumberOfHMetrics == 1) ? FlagsEnum.FixedPitch : 0;
int fsSelection = os2.FsSelection;
flags |= ((fsSelection & (ITALIC | OBLIQUE)) != 0) ? FlagsEnum.Italic : 0;
switch (os2.FamilyClass)
{
case OS2WindowsMetricsTable.FAMILY_CLASS_CLAREDON_SERIFS:
case OS2WindowsMetricsTable.FAMILY_CLASS_FREEFORM_SERIFS:
case OS2WindowsMetricsTable.FAMILY_CLASS_MODERN_SERIFS:
case OS2WindowsMetricsTable.FAMILY_CLASS_OLDSTYLE_SERIFS:
case OS2WindowsMetricsTable.FAMILY_CLASS_SLAB_SERIFS:
flags |= FlagsEnum.Serif;
break;
case OS2WindowsMetricsTable.FAMILY_CLASS_SCRIPTS:
flags |= FlagsEnum.Script;
break;
default:
break;
}
fd.FontWeight = os2.WeightClass;
flags |= FlagsEnum.Symbolic;
flags &= ~FlagsEnum.Nonsymbolic;
fd.Flags = flags;
// ItalicAngle
fd.ItalicAngle = post.ItalicAngle;
// FontBBox
HeaderTable header = ttf.Header;
float scaling = 1000f / header.UnitsPerEm;
var skRect = new SKRect(
header.XMin * scaling,
header.YMin * scaling,
header.XMax * scaling,
header.YMax * scaling
);
Rectangle rect = new Rectangle(skRect);
fd.FontBBox = rect;
// Ascent, Descent
HorizontalHeaderTable hHeader = ttf.HorizontalHeader;
fd.Ascent = hHeader.Ascender * scaling;
fd.Descent = hHeader.Descender * scaling;
// CapHeight, XHeight
if (os2.Version >= 1.2)
{
fd.CapHeight = os2.CapHeight * scaling;
fd.XHeight = os2.Height * scaling;
}
else
{
var capHPath = ttf.GetPath("H");
if (capHPath != null)
{
fd.CapHeight = (float)Math.Round(capHPath.Bounds.Bottom * scaling);
}
else
{
// estimate by summing the typographical +ve ascender and -ve descender
fd.CapHeight = os2.TypoAscender + (os2.TypoDescender * scaling);
}
var xPath = ttf.GetPath("x");
if (xPath != null)
{
fd.XHeight = (float)Math.Round(xPath.Bounds.Bottom * scaling);
}
else
{
// estimate by halving the typographical ascender
fd.XHeight = os2.TypoAscender / (2.0f * scaling);
}
}
// StemV - there's no true TTF equivalent of this, so we estimate it
fd.StemV = skRect.Width * .13f;
return(fd);
}
