public static CMapTable Load(BinaryReader reader)
{
ushort version = reader.ReadUInt16();
ushort numTables = reader.ReadUInt16();
var encodings = new EncodingRecord[numTables];
for (int i = 0; i < numTables; i++)
{
encodings[i] = EncodingRecord.Read(reader);
}
// foreach encoding we move forward looking for th subtables
var tables = new List <CMapSubTable>(numTables);
foreach (IGrouping <uint, EncodingRecord> encoding in encodings.Where(x => x.PlatformID == PlatformIDs.Windows).GroupBy(x => x.Offset))
{
reader.Seek(encoding.Key, System.IO.SeekOrigin.Begin);
ushort subTypeTableFormat = reader.ReadUInt16();
switch (subTypeTableFormat)
{
case 0:
tables.AddRange(Format0SubTable.Load(encoding, reader));
break;
case 4:
tables.AddRange(Format4SubTable.Load(encoding, reader));
break;
}
}
return(new CMapTable(tables.ToArray()));
}
[InlineData(500, 0)] //not in range
public void GetCharcter(int src, int expected)
{
// segCountX2: 8
// searchRange: 8
// entrySelector: 4
// rangeShift: 0
// endCode: 20 90 480 0xffff
// reservedPad: 0
// startCode: 10 30 153 0xffff
// dDelta: -9 -18 -27 1
// idRangeOffset: 0 0 0 0
ushort[] glyphs = Enumerable.Range(0, expected).Select(x => (ushort)x).ToArray();
Format4SubTable table = new Format4SubTable(
0,
PlatformIDs.Windows,
0,
new[]
{
new Format4SubTable.Segment(0, 20, 10, -9, 0),
new Format4SubTable.Segment(1, 90, 30, -18, 0),
new Format4SubTable.Segment(2, 480, 153, -27, 0),
},
glyphs);
ushort id = table.GetGlyphId((char)src);
Assert.Equal(expected, id);
}
public void LoadFormat4()
{
BinaryWriter writer = new BinaryWriter();
//int subtableCount = 1;
writer.WriteCMapSubTable(new SixLabors.Fonts.Tables.General.CMap.Format4SubTable(0, PlatformIDs.Windows, 2,
new[]
{
new Format4SubTable.Segment(0, 1, 2, 3, 4)
}, new ushort[] {
1, 2, 3, 4, 5, 6, 7, 8
}));
BinaryReader reader = writer.GetReader();
ushort format = reader.ReadUInt16(); // read format before we pass along as thats whet the cmap table does
Assert.Equal(4, format);
Format4SubTable table = Format4SubTable.Load(new[] { new EncodingRecord(PlatformIDs.Windows, 2, 0) }, reader).Single();
Assert.Equal(0, table.Language);
Assert.Equal(PlatformIDs.Windows, table.Platform);
Assert.Equal(2, table.Encoding);
Assert.Equal(new ushort[] {
1, 2, 3, 4, 5, 6, 7, 8
}, table.GlyphIds);
Assert.Equal(1, table.Segments.Length);
Format4SubTable.Segment seg = table.Segments[0];
Assert.Equal(0, seg.Index);
Assert.Equal(1, seg.End);
Assert.Equal(2, seg.Start);
Assert.Equal(3, seg.Delta);
Assert.Equal(4, seg.Offset);
}
public void Format4SubTableWithSegmentsHasOffByOneWhenOverflowing()
{
Segment[] segments = new[]
{
new Segment(
0,
ushort.MaxValue, // end
ushort.MinValue, // start of range
short.MaxValue, // delta
0) // zero to force correctly tested codepath
};
var tbl = new Format4SubTable(
0,
WellKnownIds.PlatformIDs.Windows,
0,
segments,
null);
const int delta = short.MaxValue + 2; // extra 2 to handle the difference between ushort and short when offsettings
const int codePoint = delta + 5;
Assert.True(tbl.TryGetGlyphId(new CodePoint(codePoint), out ushort gid));
Assert.Equal(5, gid);
}
public static void WriteCMapSubTable(this BinaryWriter writer, Format4SubTable subtable)
{
if (subtable == null)
{
return;
}
// 'cmap' Subtable Format 4:
// Type | Name | Description
// -------|----------------------------|------------------------------------------------------------------------
// uint16 | format | Format number is set to 4.
// uint16 | length | This is the length in bytes of the subtable.
// uint16 | language | Please see “Note on the language field in 'cmap' subtables“ in this document.
// uint16 | segCountX2 | 2 x segCount.
// uint16 | searchRange | 2 x (2**floor(log2(segCount)))
// uint16 | entrySelector | log2(searchRange/2)
// uint16 | rangeShift | 2 x segCount - searchRange
// uint16 | endCount[segCount] | End characterCode for each segment, last=0xFFFF.
// uint16 | reservedPad | Set to 0.
// uint16 | startCount[segCount] | Start character code for each segment.
// int16 | idDelta[segCount] | Delta for all character codes in segment.
// uint16 | idRangeOffset[segCount] | Offsets into glyphIdArray or 0
// uint16 | glyphIdArray[ ] | Glyph index array (arbitrary length)
writer.WriteUInt16(4);
writer.WriteUInt16((ushort)subtable.DataLength());
writer.WriteUInt16(subtable.Language);
int segCount = subtable.Segments.Length;
writer.WriteUInt16((ushort)(subtable.Segments.Length * 2));
double searchRange = Math.Pow(2, Math.Floor(Math.Log(segCount, 2)));
writer.WriteUInt16((ushort)searchRange);
double entrySelector = Math.Log(searchRange / 2, 2);
writer.WriteUInt16((ushort)entrySelector);
double rangeShift = (2 * segCount) - searchRange;
writer.WriteUInt16((ushort)rangeShift);
foreach (Format4SubTable.Segment seg in subtable.Segments)
{
writer.WriteUInt16(seg.End);
}
writer.WriteUInt16(0);
foreach (Format4SubTable.Segment seg in subtable.Segments)
{
writer.WriteUInt16(seg.Start);
}
foreach (Format4SubTable.Segment seg in subtable.Segments)
{
writer.WriteInt16(seg.Delta);
}
foreach (Format4SubTable.Segment seg in subtable.Segments)
{
writer.WriteUInt16(seg.Offset);
}
foreach (ushort c in subtable.GlyphIds)
{
writer.WriteUInt16(c);
}
}
