internal FakeFontInstance(
NameTable nameTable,
MaximumProfileTable maxpTable,
CMapTable cmap,
GlyphTable glyphs,
OS2Table os2,
HorizontalHeadTable horizontalHeadTable,
HorizontalMetricsTable horizontalMetrics,
VerticalHeadTable verticalHeadTable,
VerticalMetricsTable verticalMetrics,
HeadTable head,
KerningTable kern)
: base(
nameTable,
maxpTable,
cmap,
glyphs,
os2,
horizontalHeadTable,
horizontalMetrics,
verticalHeadTable,
verticalMetrics,
head,
kern,
null,
null,
null,
null,
null,
null,
null,
null)
{
}
public static HorizontalMetricsTable Load(FontReader reader)
{
// you should load all dependent tables prior to manipulating the reader
HorizontalHeadTable headTable = reader.GetTable <HorizontalHeadTable>();
MaximumProfileTable profileTable = reader.GetTable <MaximumProfileTable>();
// Move to start of table
using BigEndianBinaryReader binaryReader = reader.GetReaderAtTablePosition(TableName);
return(Load(binaryReader, headTable.NumberOfHMetrics, profileTable.GlyphCount));
}
public void ShouldThrowExceptionWhenTableCouldNotBeFound()
{
var writer = new BinaryWriter();
writer.WriteTrueTypeFileHeader();
using (var stream = writer.GetStream())
{
var exception = Assert.Throws <InvalidFontTableException>(() => MaximumProfileTable.Load(new FontReader(stream)));
Assert.Equal("maxp", exception.Table);
}
}
/// <summary> Initializes the in-memory representation </summary>
/// <param name="reader"> The reader containing the font file. </param>
private void Initialize(BinaryReader reader)
{
//actually, the header won't be implemented here. The math table will just be sought for and read.
const uint math = 0x4D415448;//literal for 'MATH' in big endianness (which the font file uses)
const uint hhea = 0x68686561;
const uint head = 0x68656164;
const uint cmap = 0x636D6170;
const uint glyf = 0x676C7966;
const uint maxp = 0x6D617870;
uint[] literals = { math, head, glyf, maxp };
TableRecord[] records = new TableRecord[literals.Length];
reader.BaseStream.Position = 0;
while (reader.BaseStream.Position < 20000)
{
uint value = reader.ReadUInt32();
int literalIndex = literals.IndexOf(value);
if (literalIndex != -1)
records[literalIndex] = new TableRecord(reader);
}
reader.BaseStream.Position = (long)records[literals.IndexOf(math)].Offset;
MathTable = new MathTable(reader);
reader.BaseStream.Position = (long)records[literals.IndexOf(head)].Offset;
Head = new Head.Head(reader);
reader.BaseStream.Position = (long)records[literals.IndexOf(maxp)].Offset;
MaximumProfileTable = new MaximumProfileTable(reader);
reader.BaseStream.Position = (long)records[literals.IndexOf(glyf)].Offset;
long end = (long)records[literals.IndexOf(glyf)].Offset + (long)records[literals.IndexOf(glyf)].Length;
GlyphTable = new Glyf.GlyfHeader(reader, MaximumProfileTable.GlyphCount, end);
}
/// <summary>
/// Initializes a new instance of the <see cref="StreamFontMetrics"/> class.
/// </summary>
/// <param name="nameTable">The name table.</param>
/// <param name="maximumProfileTable">The maximum profile table.</param>
/// <param name="cmap">The cmap table.</param>
/// <param name="glyphs">The glyph table.</param>
/// <param name="os2">The os2 table.</param>
/// <param name="horizontalHeadTable">The horizontal head table.</param>
/// <param name="horizontalMetrics">The horizontal metrics table.</param>
/// <param name="verticalHeadTable">The vertical head table.</param>
/// <param name="verticalMetrics">The vertical metrics table.</param>
/// <param name="head">The head table.</param>
/// <param name="kern">The kerning table.</param>
/// <param name="gSubTable">The glyph substitution table.</param>
/// <param name="gPosTable">The glyph positioning table.</param>
/// <param name="colrTable">The COLR table</param>
/// <param name="cpalTable">The CPAL table</param>
/// <param name="fpgm">The font program table.</param>
/// <param name="cvt">The control value table.</param>
/// <param name="prep">The control value program table.</param>
/// <param name="glyphDefinitionTable">The glyph definition table.</param>
internal StreamFontMetrics(
NameTable nameTable,
MaximumProfileTable maximumProfileTable,
CMapTable cmap,
GlyphTable glyphs,
OS2Table os2,
HorizontalHeadTable horizontalHeadTable,
HorizontalMetricsTable horizontalMetrics,
VerticalHeadTable?verticalHeadTable,
VerticalMetricsTable?verticalMetrics,
HeadTable head,
KerningTable kern,
GSubTable?gSubTable,
GPosTable?gPosTable,
ColrTable?colrTable,
CpalTable?cpalTable,
FpgmTable?fpgm,
CvtTable?cvt,
PrepTable?prep,
GlyphDefinitionTable?glyphDefinitionTable)
{
this.maximumProfileTable = maximumProfileTable;
this.cmap = cmap;
this.os2 = os2;
this.glyphs = glyphs;
this.horizontalMetrics = horizontalMetrics;
this.verticalMetricsTable = verticalMetrics;
this.head = head;
this.glyphCache = new GlyphMetrics[this.glyphs.GlyphCount][];
if (colrTable is not null)
{
this.colorGlyphCache = new GlyphMetrics[this.glyphs.GlyphCount][];
}
// https://www.microsoft.com/typography/otspec/recom.htm#tad
// We use the same approach as FreeType for calculating the the global ascender, descender, and
// height of OpenType fonts for consistency.
//
// 1.If the OS/ 2 table exists and the fsSelection bit 7 is set (USE_TYPO_METRICS), trust the font
// and use the Typo* metrics.
// 2.Otherwise, use the HorizontalHeadTable "hhea" table's metrics.
// 3.If they are zero and the OS/ 2 table exists,
// - Use the OS/ 2 table's sTypo* metrics if they are non-zero.
// - Otherwise, use the OS / 2 table's usWin* metrics.
bool useTypoMetrics = os2.FontStyle.HasFlag(OS2Table.FontStyleSelection.USE_TYPO_METRICS);
if (useTypoMetrics)
{
this.Ascender = os2.TypoAscender;
this.Descender = os2.TypoDescender;
this.LineGap = os2.TypoLineGap;
this.LineHeight = (short)(this.Ascender - this.Descender + this.LineGap);
}
else
{
this.Ascender = horizontalHeadTable.Ascender;
this.Descender = horizontalHeadTable.Descender;
this.LineGap = horizontalHeadTable.LineGap;
this.LineHeight = (short)(this.Ascender - this.Descender + this.LineGap);
}
if (this.Ascender == 0 || this.Descender == 0)
{
if (os2.TypoAscender != 0 || os2.TypoDescender != 0)
{
this.Ascender = os2.TypoAscender;
this.Descender = os2.TypoDescender;
this.LineGap = os2.TypoLineGap;
this.LineHeight = (short)(this.Ascender - this.Descender + this.LineGap);
}
else
{
this.Ascender = (short)os2.WinAscent;
this.Descender = (short)-os2.WinDescent;
this.LineHeight = (short)(this.Ascender - this.Descender);
}
}
this.UnitsPerEm = this.head.UnitsPerEm;
// 72 * UnitsPerEm means 1pt = 1px
this.ScaleFactor = this.UnitsPerEm * 72F;
this.AdvanceWidthMax = (short)horizontalHeadTable.AdvanceWidthMax;
this.AdvanceHeightMax = verticalHeadTable == null ? this.LineHeight : verticalHeadTable.AdvanceHeightMax;
this.kerningTable = kern;
this.gSubTable = gSubTable;
this.gPosTable = gPosTable;
this.colrTable = colrTable;
this.cpalTable = cpalTable;
this.fpgm = fpgm;
this.cvt = cvt;
this.prep = prep;
this.glyphDefinitionTable = glyphDefinitionTable;
this.Description = new FontDescription(nameTable, os2, head);
}
