private static CoverageTable GetSubtablePrincipalCoverage(
FontTable table,
OpenTypeTags tableTag,
ushort lookupType,
int subtableOffset
)
{
Debug.Assert(tableTag == OpenTypeTags.GSUB || tableTag == OpenTypeTags.GPOS);
CoverageTable coverage = CoverageTable.InvalidCoverage;
switch (tableTag)
{
case OpenTypeTags.GSUB:
if (lookupType == 7)
{
ExtensionLookupTable extension =
new ExtensionLookupTable(subtableOffset);
lookupType = extension.LookupType(table);
subtableOffset = extension.LookupSubtableOffset(table);
}
switch (lookupType)
{
case 1: //SingleSubst
SingleSubstitutionSubtable singleSubst =
new SingleSubstitutionSubtable(subtableOffset);
return(singleSubst.GetPrimaryCoverage(table));
case 2: //MultipleSubst
MultipleSubstitutionSubtable multipleSub =
new MultipleSubstitutionSubtable(subtableOffset);
return(multipleSub.GetPrimaryCoverage(table));
case 3: //AlternateSubst
AlternateSubstitutionSubtable alternateSub =
new AlternateSubstitutionSubtable(subtableOffset);
return(alternateSub.GetPrimaryCoverage(table));
case 4: //Ligature subst
LigatureSubstitutionSubtable ligaSub =
new LigatureSubstitutionSubtable(subtableOffset);
return(ligaSub.GetPrimaryCoverage(table));
case 5: //ContextualSubst
ContextSubtable contextSub =
new ContextSubtable(subtableOffset);
return(contextSub.GetPrimaryCoverage(table));
case 6: //ChainingSubst
ChainingSubtable chainingSub =
new ChainingSubtable(subtableOffset);
return(chainingSub.GetPrimaryCoverage(table));
case 7: //Extension lookup
// Ext.Lookup processed earlier. It can't contain another ext.lookups in it
break;
case 8: //ReverseCahiningSubst
ReverseChainingSubtable reverseChainingSub =
new ReverseChainingSubtable(subtableOffset);
return(reverseChainingSub.GetPrimaryCoverage(table));
}
break;
case OpenTypeTags.GPOS:
if (lookupType == 9)
{
ExtensionLookupTable extension =
new ExtensionLookupTable(subtableOffset);
lookupType = extension.LookupType(table);
subtableOffset = extension.LookupSubtableOffset(table);
}
switch (lookupType)
{
case 1: //SinglePos
SinglePositioningSubtable singlePos =
new SinglePositioningSubtable(subtableOffset);
return(singlePos.GetPrimaryCoverage(table));
case 2: //PairPos
PairPositioningSubtable pairPos =
new PairPositioningSubtable(subtableOffset);
return(pairPos.GetPrimaryCoverage(table));
case 3: // CursivePos
CursivePositioningSubtable cursivePos =
new CursivePositioningSubtable(subtableOffset);
return(cursivePos.GetPrimaryCoverage(table));
case 4: //MarkToBasePos
MarkToBasePositioningSubtable markToBasePos =
new MarkToBasePositioningSubtable(subtableOffset);
return(markToBasePos.GetPrimaryCoverage(table));
case 5: //MarkToLigaturePos
// Under construction
MarkToLigaturePositioningSubtable markToLigaPos =
new MarkToLigaturePositioningSubtable(subtableOffset);
return(markToLigaPos.GetPrimaryCoverage(table));
case 6: //MarkToMarkPos
MarkToMarkPositioningSubtable markToMarkPos =
new MarkToMarkPositioningSubtable(subtableOffset);
return(markToMarkPos.GetPrimaryCoverage(table));
case 7: // Contextual
ContextSubtable contextPos =
new ContextSubtable(subtableOffset);
return(contextPos.GetPrimaryCoverage(table));
case 8: // Chaining
ChainingSubtable chainingPos =
new ChainingSubtable(subtableOffset);
return(chainingPos.GetPrimaryCoverage(table));
case 9: //Extension lookup
// Ext.Lookup processed earlier. It can't contain another ext.lookups in it
break;
}
break;
}
return(CoverageTable.InvalidCoverage);
}