internal static SequenceLookupRecord[] LoadSequenceContextFormat3(BigEndianBinaryReader reader, long offset, out CoverageTable[] coverageTables)
{
// https://docs.microsoft.com/en-us/typography/opentype/spec/chapter2#sequence-context-format-3-coverage-based-glyph-contexts
// SequenceContextFormat3
// +----------------------+----------------------------------+-------------------------------------------+
// | Type | Name | Description |
// +======================+==================================+===========================================+
// | uint16 | format | Format identifier: format = 3 |
// +----------------------+----------------------------------+-------------------------------------------+
// | uint16 | glyphCount | Number of glyphs in the input sequence |
// +----------------------+----------------------------------+-------------------------------------------+
// | uint16 | seqLookupCount | Number of SequenceLookupRecords |
// +----------------------+----------------------------------+-------------------------------------------+
// | Offset16 | coverageOffsets[glyphCount] | Array of offsets to Coverage tables, from |
// | | | beginning of SequenceContextFormat3 |
// | | | subtable |
// +----------------------+----------------------------------+-------------------------------------------+
// | SequenceLookupRecord | seqLookupRecords[seqLookupCount] | Array of SequenceLookupRecords |
// +----------------------+----------------------------------+-------------------------------------------+
ushort glyphCount = reader.ReadUInt16();
ushort seqLookupCount = reader.ReadUInt16();
ushort[] coverageOffsets = reader.ReadUInt16Array(glyphCount);
SequenceLookupRecord[] seqLookupRecords = SequenceLookupRecord.LoadArray(reader, seqLookupCount);
coverageTables = new CoverageTable[glyphCount];
for (int i = 0; i < coverageTables.Length; i++)
{
coverageTables[i] = CoverageTable.Load(reader, offset + coverageOffsets[i]);
}
return(seqLookupRecords);
}
internal static SequenceRuleSetTable[] LoadSequenceContextFormat1(BigEndianBinaryReader reader, long offset, out CoverageTable coverageTable)
{
// https://docs.microsoft.com/en-us/typography/opentype/spec/chapter2#seqctxt1
// SequenceContextFormat1
// +----------+------------------------------------+---------------------------------------------------------------+
// | Type | Name | Description |
// +==========+====================================+===============================================================+
// | uint16 | format | Format identifier: format = 1 |
// +----------+------------------------------------+---------------------------------------------------------------+
// | Offset16 | coverageOffset | Offset to Coverage table, from beginning of |
// | | | SequenceContextFormat1 table. |
// +----------+------------------------------------+---------------------------------------------------------------+
// | uint16 | seqRuleSetCount | Number of SequenceRuleSet tables. |
// +----------+------------------------------------+---------------------------------------------------------------+
// | Offset16 | seqRuleSetOffsets[seqRuleSetCount] | Array of offsets to SequenceRuleSet tables, from beginning of |
// | | | SequenceContextFormat1 table (offsets may be NULL). |
// +----------+------------------------------------+---------------------------------------------------------------+
ushort coverageOffset = reader.ReadOffset16();
ushort seqRuleSetCount = reader.ReadUInt16();
using Buffer <ushort> seqRuleSetOffsetsBuffer = new(seqRuleSetCount);
Span <ushort> seqRuleSetOffsets = seqRuleSetOffsetsBuffer.GetSpan();
reader.ReadUInt16Array(seqRuleSetOffsets);
var seqRuleSets = new SequenceRuleSetTable[seqRuleSetCount];
for (int i = 0; i < seqRuleSets.Length; i++)
{
seqRuleSets[i] = SequenceRuleSetTable.Load(reader, offset + seqRuleSetOffsets[i]);
}
coverageTable = CoverageTable.Load(reader, offset + coverageOffset);
return(seqRuleSets);
}
internal static SequenceLookupRecord[] LoadChainedSequenceContextFormat3(
BigEndianBinaryReader reader,
long offset,
out CoverageTable[] backtrackCoverageTables,
out CoverageTable[] inputCoverageTables,
out CoverageTable[] lookaheadCoverageTables)
{
// https://docs.microsoft.com/en-us/typography/opentype/spec/chapter2#chseqctxt3
// ChainedSequenceContextFormat3 1
// +----------------------+-----------------------------------------------+----------------------------------------------------------------+
// | Type | Name | Description |
// +======================+===============================================+================================================================+
// | uint16 | format | Format identifier: format = 3 |
// +----------------------+-----------------------------------------------+----------------------------------------------------------------+
// | uint16 | backtrackGlyphCount | Number of glyphs in the backtrack sequence |
// +----------------------+-----------------------------------------------+----------------------------------------------------------------+
// | Offset16 | backtrackCoverageOffsets[backtrackGlyphCount] | Array of offsets to coverage tables for the backtrack sequence |
// +----------------------+-----------------------------------------------+----------------------------------------------------------------+
// | uint16 | inputGlyphCount | Number of glyphs in the input sequence |
// +----------------------+-----------------------------------------------+----------------------------------------------------------------+
// | Offset16 | inputCoverageOffsets[inputGlyphCount] | Array of offsets to coverage tables for the input sequence |
// +----------------------+-----------------------------------------------+----------------------------------------------------------------+
// | uint16 | lookaheadGlyphCount | Number of glyphs in the lookahead sequence |
// +----------------------+-----------------------------------------------+----------------------------------------------------------------+
// | Offset16 | lookaheadCoverageOffsets[lookaheadGlyphCount] | Array of offsets to coverage tables for the lookahead sequence |
// +----------------------+-----------------------------------------------+----------------------------------------------------------------+
// | uint16 | seqLookupCount | Number of SequenceLookupRecords |
// +----------------------+-----------------------------------------------+----------------------------------------------------------------+
// | SequenceLookupRecord | seqLookupRecords[seqLookupCount] | Array of SequenceLookupRecords |
// +----------------------+-----------------------------------------------+----------------------------------------------------------------+
ushort backtrackGlyphCount = reader.ReadUInt16();
ushort[] backtrackCoverageOffsets = reader.ReadUInt16Array(backtrackGlyphCount);
ushort inputGlyphCount = reader.ReadUInt16();
ushort[] inputCoverageOffsets = reader.ReadUInt16Array(inputGlyphCount);
ushort lookaheadGlyphCount = reader.ReadUInt16();
ushort[] lookaheadCoverageOffsets = reader.ReadUInt16Array(lookaheadGlyphCount);
ushort seqLookupCount = reader.ReadUInt16();
SequenceLookupRecord[] seqLookupRecords = SequenceLookupRecord.LoadArray(reader, seqLookupCount);
backtrackCoverageTables = CoverageTable.LoadArray(reader, offset, backtrackCoverageOffsets);
inputCoverageTables = CoverageTable.LoadArray(reader, offset, inputCoverageOffsets);
lookaheadCoverageTables = CoverageTable.LoadArray(reader, offset, lookaheadCoverageOffsets);
return(seqLookupRecords);
}
internal static CoverageTable LoadSequenceContextFormat2(BigEndianBinaryReader reader, long offset, out ClassDefinitionTable classDefTable, out ClassSequenceRuleSetTable[] classSeqRuleSets)
{
// https://docs.microsoft.com/en-us/typography/opentype/spec/chapter2#sequence-context-format-2-class-based-glyph-contexts
// Context Positioning Subtable Format 2: Class-based Glyph Contexts.
// +----------+----------------------------------------------+--------------------------------------------------------------------+
// | Type | Name | Description |
// +==========+==============================================+====================================================================+
// | uint16 | format | Format identifier: format = 2 |
// +----------+----------------------------------------------+--------------------------------------------------------------------+
// | Offset16 | coverageOffset | Offset to Coverage table, from beginning of |
// | | | SequenceContextFormat2 table. |
// +----------+----------------------------------------------+--------------------------------------------------------------------+
// | Offset16 | classDefOffset | Offset to ClassDef table, from beginning of |
// | | | SequenceContextFormat2 table. |
// +----------+----------------------------------------------+--------------------------------------------------------------------+
// | uint16 | classSeqRuleSetCount | Number of ClassSequenceRuleSet tables. |
// +----------+----------------------------------------------+--------------------------------------------------------------------+
// | Offset16 | classSeqRuleSetOffsets[classSeqRuleSetCount] | Array of offsets to ClassSequenceRuleSet tables, from beginning of |
// | | | SequenceContextFormat2 table (may be NULL). |
// +----------+----------------------------------------------+--------------------------------------------------------------------+
ushort coverageOffset = reader.ReadOffset16();
ushort classDefOffset = reader.ReadOffset16();
ushort classSeqRuleSetCount = reader.ReadUInt16();
using Buffer <ushort> classSeqRuleSetOffsetsBuffer = new(classSeqRuleSetCount);
Span <ushort> classSeqRuleSetOffsets = classSeqRuleSetOffsetsBuffer.GetSpan();
reader.ReadUInt16Array(classSeqRuleSetOffsets);
var coverageTable = CoverageTable.Load(reader, offset + coverageOffset);
classDefTable = ClassDefinitionTable.Load(reader, offset + classDefOffset);
classSeqRuleSets = new ClassSequenceRuleSetTable[classSeqRuleSetCount];
for (int i = 0; i < classSeqRuleSets.Length; i++)
{
ushort ruleSetOffset = classSeqRuleSetOffsets[i];
if (ruleSetOffset > 0)
{
classSeqRuleSets[i] = ClassSequenceRuleSetTable.Load(reader, offset + classSeqRuleSetOffsets[i]);
}
}
return(coverageTable);
}
internal static ChainedSequenceRuleSetTable[] LoadChainedSequenceContextFormat1(BigEndianBinaryReader reader, long offset, out CoverageTable coverageTable)
{
// https://docs.microsoft.com/en-us/typography/opentype/spec/chapter2#chained-sequence-context-format-1-simple-glyph-contexts
// ChainedSequenceContextFormat1
// +----------+--------------------------------------------------+------------------------------------------+
// | Type | Name | Description |
// +==========+==================================================+==========================================+
// | uint16 | format | Format identifier: format = 1 |
// +----------+--------------------------------------------------+------------------------------------------+
// | Offset16 | coverageOffset | Offset to Coverage table, from beginning |
// | | | of ChainSequenceContextFormat1 table |
// +----------+--------------------------------------------------+------------------------------------------+
// | uint16 | chainedSeqRuleSetCount | Number of ChainedSequenceRuleSet tables |
// +----------+--------------------------------------------------+------------------------------------------+
// | Offset16 | chainedSeqRuleSetOffsets[chainedSeqRuleSetCount] | Array of offsets to ChainedSeqRuleSet |
// | | | tables, from beginning of |
// | | | ChainedSequenceContextFormat1 table |
// | | | (may be NULL) |
// +----------+--------------------------------------------------+------------------------------------------+
ushort coverageOffset = reader.ReadOffset16();
ushort chainedSeqRuleSetCount = reader.ReadUInt16();
using Buffer <ushort> chainedSeqRuleSetOffsetsBuffer = new(chainedSeqRuleSetCount);
Span <ushort> chainedSeqRuleSetOffsets = chainedSeqRuleSetOffsetsBuffer.GetSpan();
reader.ReadUInt16Array(chainedSeqRuleSetOffsets);
var seqRuleSets = new ChainedSequenceRuleSetTable[chainedSeqRuleSetCount];
for (int i = 0; i < seqRuleSets.Length; i++)
{
if (chainedSeqRuleSetOffsets[i] > 0)
{
seqRuleSets[i] = ChainedSequenceRuleSetTable.Load(reader, offset + chainedSeqRuleSetOffsets[i]);
}
}
coverageTable = CoverageTable.Load(reader, offset + coverageOffset);
return(seqRuleSets);
}
public static AttachmentListTable Load(BigEndianBinaryReader reader, long offset)
{
// Attachment Point List Table
// Type | Name | Description
// ----------|--------------------------------|--------------------------------------------------------------------------------------------------------
// Offset16 | coverageOffset | Offset to Coverage table -from beginning of AttachList table.
// ----------|--------------------------------|--------------------------------------------------------------------------------------------------------
// uint16 | glyphCount | Number of glyphs with attachment points.
// ----------|--------------------------------|--------------------------------------------------------------------------------------------------------
// Offset16 | attachPointOffsets[glyphCount] | Array of offsets to AttachPoint tables-from beginning of AttachList table-in Coverage Index order.
// ----------|--------------------------------|--------------------------------------------------------------------------------------------------------
reader.Seek(offset, SeekOrigin.Begin);
ushort coverageOffset = reader.ReadUInt16();
ushort glyphCount = reader.ReadUInt16();
using Buffer <ushort> attachPointOffsetsBuffer = new(glyphCount);
Span <ushort> attachPointOffsets = attachPointOffsetsBuffer.GetSpan();
reader.ReadUInt16Array(attachPointOffsets);
var attachmentListTable = new AttachmentListTable
{
CoverageTable = CoverageTable.Load(reader, offset + coverageOffset),
AttachPoints = new AttachPoint[glyphCount]
};
for (int i = 0; i < glyphCount; ++i)
{
reader.Seek(offset + attachPointOffsets[i], SeekOrigin.Begin);
ushort pointCount = reader.ReadUInt16();
attachmentListTable.AttachPoints[i] = new AttachPoint()
{
PointIndices = reader.ReadUInt16Array(pointCount)
};
}
return(attachmentListTable);
}
internal static ChainedClassSequenceRuleSetTable[] LoadChainedSequenceContextFormat2(
BigEndianBinaryReader reader,
long offset,
out CoverageTable coverageTable,
out ClassDefinitionTable backtrackClassDefTable,
out ClassDefinitionTable inputClassDefTable,
out ClassDefinitionTable lookaheadClassDefTable)
{
// https://docs.microsoft.com/en-us/typography/opentype/spec/chapter2#chained-sequence-context-format-2-class-based-glyph-contexts
// ChainedSequenceContextFormat2
// +----------+------------------------------------------------------------+---------------------------------------------------------------------+
// | Type | Name | Description |
// +==========+============================================================+=====================================================================+
// | uint16 | format | Format identifier: format = 2 |
// +----------+------------------------------------------------------------+---------------------------------------------------------------------+
// | Offset16 | coverageOffset | Offset to Coverage table, from beginning |
// | | | of ChainedSequenceContextFormat2 table |
// +----------+------------------------------------------------------------+---------------------------------------------------------------------+
// | Offset16 | backtrackClassDefOffset | Offset to ClassDef table containing |
// | | | backtrack sequence context, from |
// | | | beginning of ChainedSequenceContextFormat2 table |
// +----------+------------------------------------------------------------+---------------------------------------------------------------------+
// | Offset16 | inputClassDefOffset | Offset to ClassDef table containing input |
// | | | sequence context, from beginning of |
// | | | ChainedSequenceContextFormat2 table |
// +----------+------------------------------------------------------------+---------------------------------------------------------------------+
// | Offset16 | lookaheadClassDefOffset | Offset to ClassDef table containing |
// | | | lookahead sequence context, from |
// | | | beginning of ChainedSequenceContextFormat2 table |
// +----------+------------------------------------------------------------+---------------------------------------------------------------------+
// | uint16 | chainedClassSeqRuleSetCount | Number of ChainedClassSequenceRuleSet tables |
// +----------+------------------------------------------------------------+---------------------------------------------------------------------+
// | Offset16 | chainedClassSeqRuleSetOffsets[chainedClassSeqRuleSetCount] | Array of offsets to ChainedClassSequenceRuleSet tables, |
// | | | from beginning of ChainedSequenceContextFormat2 table (may be NULL) |
// +----------+------------------------------------------------------------+---------------------------------------------------------------------+
ushort coverageOffset = reader.ReadOffset16();
ushort backtrackClassDefOffset = reader.ReadOffset16();
ushort inputClassDefOffset = reader.ReadOffset16();
ushort lookaheadClassDefOffset = reader.ReadOffset16();
ushort chainedClassSeqRuleSetCount = reader.ReadUInt16();
ChainedClassSequenceRuleSetTable[] seqRuleSets = Array.Empty <ChainedClassSequenceRuleSetTable>();
if (chainedClassSeqRuleSetCount != 0)
{
ushort[] chainedClassSeqRuleSetOffsets = new ushort[chainedClassSeqRuleSetCount];
for (int i = 0; i < chainedClassSeqRuleSetCount; i++)
{
chainedClassSeqRuleSetOffsets[i] = reader.ReadOffset16();
}
seqRuleSets = new ChainedClassSequenceRuleSetTable[chainedClassSeqRuleSetCount];
for (int i = 0; i < seqRuleSets.Length; i++)
{
if (chainedClassSeqRuleSetOffsets[i] > 0)
{
seqRuleSets[i] =
ChainedClassSequenceRuleSetTable.Load(reader, offset + chainedClassSeqRuleSetOffsets[i]);
}
}
}
coverageTable = CoverageTable.Load(reader, offset + coverageOffset);
backtrackClassDefTable = ClassDefinitionTable.Load(reader, offset + backtrackClassDefOffset);
inputClassDefTable = ClassDefinitionTable.Load(reader, offset + inputClassDefOffset);
lookaheadClassDefTable = ClassDefinitionTable.Load(reader, offset + lookaheadClassDefOffset);
return(seqRuleSets);
}
