public bool IsLookupCovered(
FontTable table,
uint[] glyphBits,
ushort minGlyphId,
ushort maxGlyphId)
{
if (!Coverage(table).IsAnyGlyphCovered(table,
glyphBits,
minGlyphId,
maxGlyphId
)
)
{
return(false);
}
ushort ligatureSetCount = LigatureSetCount(table);
for (ushort setIndex = 0; setIndex < ligatureSetCount; setIndex++)
{
LigatureSetTable ligatureSet = LigatureSet(table, setIndex);
ushort ligaCount = ligatureSet.LigatureCount(table);
for (ushort liga = 0; liga < ligaCount; liga++)
{
LigatureTable ligature = ligatureSet.Ligature(table, liga);
ushort compCount = ligature.ComponentCount(table);
bool ligatureIsComplex = true;
for (ushort compIndex = 1; compIndex < compCount; compIndex++)
{
ushort glyphId = ligature.Component(table, compIndex);
if (glyphId > maxGlyphId ||
glyphId < minGlyphId ||
(glyphBits[glyphId >> 5] & (1 << (glyphId % 32))) == 0
)
{
ligatureIsComplex = false;
break;
}
}
if (ligatureIsComplex)
{
return(true);
}
}
}
return(false);
}
private void ExtractDataFromLigatureTable(Dictionary <List <int>, int> glyphSubstitutionMap,
LigatureTable ligatureTable)
{
List <int> glyphsToBeSubstituted = new List <int>();
foreach (int componentGlyphID in ligatureTable.ComponentGlyphIDs)
{
glyphsToBeSubstituted.Add(componentGlyphID);
}
Debug.WriteLine($"debug: glyphsToBeSubstituted: {glyphsToBeSubstituted}");
PutNewSubstitutionEntry(glyphSubstitutionMap, ligatureTable.LigatureGlyph,
glyphsToBeSubstituted);
}
public unsafe bool Apply(
IOpenTypeFont Font,
FontTable Table,
int CharCount,
UshortList Charmap, // Character to glyph map
GlyphInfoList GlyphInfo, // List of GlyphInfo
ushort LookupFlags, // Lookup flags for glyph lookups
int FirstGlyph, // where to apply it
int AfterLastGlyph, // how long is a context we can use
out int NextGlyph // Next glyph to process
)
{
Invariant.Assert(FirstGlyph >= 0);
Invariant.Assert(AfterLastGlyph <= GlyphInfo.Length);
NextGlyph = FirstGlyph + 1; //In case we don't match;
if (Format(Table) != 1)
{
return(false); // Unknown format
}
int glyphCount = GlyphInfo.Length;
ushort glyphId = GlyphInfo.Glyphs[FirstGlyph];
int CoverageIndex = Coverage(Table).GetGlyphIndex(Table, glyphId);
if (CoverageIndex == -1)
{
return(false);
}
int curGlyph;
ushort ligatureGlyph = 0;
bool match = false;
ushort compCount = 0;
LigatureSetTable ligatureSet = LigatureSet(Table, (ushort)CoverageIndex);
ushort ligaCount = ligatureSet.LigatureCount(Table);
for (ushort liga = 0; liga < ligaCount; liga++)
{
LigatureTable ligature = ligatureSet.Ligature(Table, liga);
compCount = ligature.ComponentCount(Table);
if (compCount == 0)
{
throw new FileFormatException();
}
curGlyph = FirstGlyph;
ushort comp = 1;
for (comp = 1; comp < compCount; comp++)
{
curGlyph = LayoutEngine.GetNextGlyphInLookup(Font, GlyphInfo, curGlyph + 1, LookupFlags, LayoutEngine.LookForward);
if (curGlyph >= AfterLastGlyph)
{
break;
}
if (GlyphInfo.Glyphs[curGlyph] != ligature.Component(Table, comp))
{
break;
}
}
if (comp == compCount) //liga matched
{
match = true;
ligatureGlyph = ligature.LigatureGlyph(Table);
break; //Liga found
}
}
//If no ligature found, match will remain false after last iteration
if (match)
{
//Fix character and glyph Mapping
//PERF: localize ligature character range
//Calculate Ligature CharCount
int totalLigaCharCount = 0;
int firstLigaChar = int.MaxValue;
curGlyph = FirstGlyph;
for (ushort comp = 0; comp < compCount; comp++)
{
Invariant.Assert(curGlyph < AfterLastGlyph);
int curFirstChar = GlyphInfo.FirstChars[curGlyph];
int curLigaCount = GlyphInfo.LigatureCounts[curGlyph];
totalLigaCharCount += curLigaCount;
if (curFirstChar < firstLigaChar)
{
firstLigaChar = curFirstChar;
}
curGlyph = LayoutEngine.GetNextGlyphInLookup(Font, GlyphInfo, curGlyph + 1, LookupFlags, LayoutEngine.LookForward);
}
curGlyph = FirstGlyph;
int prevGlyph = FirstGlyph;
ushort shift = 0;
for (ushort comp = 1; comp <= compCount; comp++)
{
prevGlyph = curGlyph;
if (comp < compCount)
{
curGlyph = LayoutEngine.
GetNextGlyphInLookup(Font, GlyphInfo,
curGlyph + 1,
LookupFlags,
LayoutEngine.LookForward);
}
else
{
curGlyph = GlyphInfo.Length; // to the end from last component
}
// Set charmap for ligature component
for (int curChar = 0; curChar < CharCount; curChar++)
{
if (Charmap[curChar] == prevGlyph)
{
Charmap[curChar] = (ushort)FirstGlyph;
}
}
//Shift glyphInfo
if (shift > 0)
{
for (int glyph = prevGlyph + 1; glyph < curGlyph; glyph++)
{
GlyphInfo.Glyphs[glyph - shift] = GlyphInfo.Glyphs[glyph];
GlyphInfo.GlyphFlags[glyph - shift] = GlyphInfo.GlyphFlags[glyph];
GlyphInfo.FirstChars[glyph - shift] = GlyphInfo.FirstChars[glyph];
GlyphInfo.LigatureCounts[glyph - shift] = GlyphInfo.LigatureCounts[glyph];
}
if (curGlyph - prevGlyph > 1) //do fixing only if have glyphs in between
{
for (int curChar = 0; curChar < CharCount; curChar++)
{
ushort curCharmap = Charmap[curChar];
if (curCharmap > prevGlyph && curCharmap < curGlyph)
{
Charmap[curChar] -= shift;
}
}
}
}
++shift;
}
//Place new glyph into position of first ligature glyph
GlyphInfo.Glyphs[FirstGlyph] = ligatureGlyph;
GlyphInfo.GlyphFlags[FirstGlyph] = (ushort)(GlyphFlags.Unresolved | GlyphFlags.Substituted);
GlyphInfo.FirstChars[FirstGlyph] = (ushort)firstLigaChar;
GlyphInfo.LigatureCounts[FirstGlyph] = (ushort)totalLigaCharCount;
//remove empty space
if (compCount > 1)
{
GlyphInfo.Remove(GlyphInfo.Length - compCount + 1, compCount - 1);
}
NextGlyph = prevGlyph - (compCount - 1) + 1;
}
return(match);
}
public static LigatureTable CreateFrom(BinaryReader reader, long beginAt)
{
reader.BaseStream.Seek(beginAt, SeekOrigin.Begin);
//
LigatureTable ligTable = new LigatureTable();
ligTable.GlyphId = reader.ReadUInt16();
ushort compCount = reader.ReadUInt16();
ligTable.ComponentGlyphs = Utils.ReadUInt16Array(reader, compCount);
return ligTable;
}
