public unsafe bool Apply(
IOpenTypeFont Font, // Font access interface
OpenTypeTags TableTag, // Layout table tag (GSUB or GPOS)
FontTable Table, // Layout table (GSUB or GPOS)
LayoutMetrics Metrics, // LayoutMetrics
ClassDefTable inputClassDef,
ClassDefTable backtrackClassDef,
ClassDefTable lookaheadClassDef,
int CharCount, // Characters count (i.e. Charmap.Length);
UshortList Charmap, // Char to glyph mapping
GlyphInfoList GlyphInfo, // List of GlyphInfo structs
int* Advances, // Glyph adv.widths
LayoutOffset* Offsets, // Glyph offsets
ushort LookupFlags, // Lookup table flags
int FirstGlyph, // where to apply it
int AfterLastGlyph, // how long is a context we can use
uint Parameter, // lookup parameter
int nestingLevel, // Contextual lookup nesting level
out int NextGlyph // out: next glyph index
)
{
bool match = true;
NextGlyph = FirstGlyph + 1; //In case we don't match
//We are moving through table. We can pick glyph count or glyph class id.
int curOffset = offset;
int glyphIndex;
//
//Check backtrack sequence
//
int backtrackGlyphCount = GlyphCount(Table,curOffset);
curOffset += sizeCount;
glyphIndex = FirstGlyph;
for(ushort backtrackIndex = 0;
backtrackIndex < backtrackGlyphCount && match;
backtrackIndex++)
{
glyphIndex = LayoutEngine.GetNextGlyphInLookup(Font, GlyphInfo,
glyphIndex-1,
LookupFlags,
LayoutEngine.LookBackward
);
if (glyphIndex<0)
{
match = false;
}
else
{
ushort classId = ClassId(Table,curOffset);
curOffset+=sizeClassId;
ushort glyphClass = backtrackClassDef.
GetClass(Table,GlyphInfo.Glyphs[glyphIndex]);
match = (glyphClass == classId);
}
}
if (!match) return false;
//
// Check input sequence
//
int inputGlyphCount = GlyphCount(Table,curOffset);
curOffset += sizeCount;
glyphIndex = FirstGlyph;
for(ushort inputIndex = 1; //go from second glyph in the input
inputIndex < inputGlyphCount && match;
inputIndex++)
{
glyphIndex = LayoutEngine.GetNextGlyphInLookup(Font, GlyphInfo,
glyphIndex+1,
LookupFlags,
LayoutEngine.LookForward
);
if (glyphIndex >= AfterLastGlyph)
{
match = false;
}
else
{
ushort classId = ClassId(Table,curOffset);
curOffset+=sizeClassId;
ushort glyphClass = inputClassDef.
GetClass(Table,GlyphInfo.Glyphs[glyphIndex]);
match = (glyphClass == classId);
}
}
if (!match) return false;
int afterInputGlyph = glyphIndex + 1; // remember where we were after input seqence
//
// Check lookahead sequence
//
int lookaheadGlyphCount = GlyphCount(Table,curOffset);
curOffset += sizeCount;
// Lokahead sequence starting right after input,
// no need to change current glyphIndex
for(ushort lookaheadIndex = 0;
lookaheadIndex < lookaheadGlyphCount && match;
lookaheadIndex++)
{
glyphIndex = LayoutEngine.GetNextGlyphInLookup(Font, GlyphInfo,
glyphIndex+1,
LookupFlags,
LayoutEngine.LookForward
);
if (glyphIndex >= GlyphInfo.Length)
{
match = false;
}
else
{
ushort classId = ClassId(Table,curOffset);
curOffset+=sizeClassId;
ushort glyphClass = lookaheadClassDef.
GetClass(Table,GlyphInfo.Glyphs[glyphIndex]);
match = (glyphClass == classId);
}
}
if (match)
{
ContextualLookups(Table,curOffset).ApplyContextualLookups(
Font,
TableTag,
Table,
Metrics,
CharCount,
Charmap,
GlyphInfo,
Advances,
Offsets,
LookupFlags,
FirstGlyph,
afterInputGlyph, //As AfterLastGlyph
Parameter,
nestingLevel,
out NextGlyph
);
}
return match;
}
public unsafe bool Apply(
IOpenTypeFont Font, // Font access interface
OpenTypeTags TableTag, // Layout table tag (GSUB or GPOS)
FontTable Table, // Layout table (GSUB or GPOS)
LayoutMetrics Metrics, // LayoutMetrics
ClassDefTable ClassDef,
int CharCount, // Characters count (i.e. Charmap.Length);
UshortList Charmap, // Char to glyph mapping
GlyphInfoList GlyphInfo, // List of GlyphInfo structs
int* Advances, // Glyph adv.widths
LayoutOffset* Offsets, // Glyph offsets
ushort LookupFlags, // Lookup table flags
int FirstGlyph, // where to apply it
int AfterLastGlyph, // how long is a context we can use
uint Parameter, // lookup parameter
int nestingLevel, // Contextual lookup nesting level
out int NextGlyph // out: next glyph index
)
{
NextGlyph = FirstGlyph + 1; //In case we don't match
//
// Check input sequence
//
bool match = true;
int glyphIndex = FirstGlyph;
int inputGlyphCount = GlyphCount(Table);
for(ushort inputIndex = 1; // go from second glyph in the input
inputIndex < inputGlyphCount && match;
inputIndex++)
{
glyphIndex = LayoutEngine.GetNextGlyphInLookup(Font, GlyphInfo,
glyphIndex+1,
LookupFlags,
LayoutEngine.LookForward
);
if (glyphIndex>=AfterLastGlyph)
{
match = false;
}
else
{
ushort classId = ClassId(Table,inputIndex);
ushort glyphClass =
ClassDef.GetClass(Table,GlyphInfo.Glyphs[glyphIndex]);
match = (glyphClass == classId);
}
}
if (match)
{
ContextualLookups(Table).ApplyContextualLookups(
Font,
TableTag,
Table,
Metrics,
CharCount,
Charmap,
GlyphInfo,
Advances,
Offsets,
LookupFlags,
FirstGlyph,
glyphIndex + 1, //As AfterLastGlyph
Parameter,
nestingLevel,
out NextGlyph
);
}
return match;
}