public FeatureTable FindFeature(FontTable Table, FeatureList Features, uint FeatureTag)
{
ushort featureCount = FeatureCount(Table);
for(ushort i=0;i<featureCount;i++)
{
ushort featureIndex = GetFeatureIndex(Table,i);
if (Features.FeatureTag(Table,featureIndex) == FeatureTag)
{
return Features.FeatureTable(Table,featureIndex);
}
}
return new FeatureTable(FontTable.InvalidOffset);
}
internal static void GetComplexLanguageList(
OpenTypeTags tableTag,
FontTable table,
uint[] featureTagsList,
uint[] glyphBits,
ushort minGlyphId,
ushort maxGlyphId,
out WritingSystem[] complexLanguages,
out int complexLanguageCount
)
{
ScriptList scriptList = new ScriptList(0);
FeatureList featureList = new FeatureList(0);
LookupList lookupList = new LookupList(0);
Debug.Assert(tableTag == OpenTypeTags.GSUB || tableTag == OpenTypeTags.GPOS);
switch (tableTag)
{
case OpenTypeTags.GSUB:
GSUBHeader gsubHeader = new GSUBHeader(0);
scriptList = gsubHeader.GetScriptList(table);
featureList = gsubHeader.GetFeatureList(table);
lookupList = gsubHeader.GetLookupList(table);
break;
case OpenTypeTags.GPOS:
GPOSHeader gposHeader = new GPOSHeader(0);
scriptList = gposHeader.GetScriptList(table);
featureList = gposHeader.GetFeatureList(table);
lookupList = gposHeader.GetLookupList(table);
break;
}
int scriptCount = scriptList.GetScriptCount(table);
int featureCount = featureList.FeatureCount(table);
int lookupCount = lookupList.LookupCount(table);
// We will mark lookups that should be tested.
// At the end, we will have only complex ones marked
uint[] lookupBits = new uint[(lookupCount+31)>>5];
for(int i = 0; i < (lookupCount+31)>>5; i++)
{
lookupBits[i] = 0;
}
// Iterate through list of featuers in the table
for(ushort featureIndex = 0; featureIndex < featureCount; featureIndex++)
{
uint featureTag = (uint)featureList.FeatureTag(table, featureIndex);
bool tagFound = false;
//Search for tag in the list of features in question
for(int j = 0; j < featureTagsList.Length; j++)
{
if (featureTagsList[j] == featureTag)
{
tagFound = true;
break;
}
}
if (tagFound)
{
// We should mark all lookup mapped to this feature
FeatureTable featureTable = featureList.FeatureTable(table, featureIndex);
ushort featureLookupCount = featureTable.LookupCount(table);
for(ushort j = 0; j < featureLookupCount; j++)
{
ushort lookupIndex = featureTable.LookupIndex(table, j);
if (lookupIndex >= lookupCount)
{
//This should be invalid font. Lookup associated with the feature is not in lookup array.
throw new FileFormatException();
}
lookupBits[lookupIndex>>5] |= (uint)(1 << (lookupIndex%32));
}
}
}
//
//
//Now test all marked lookups
for(ushort lookupIndex = 0; lookupIndex < lookupCount; lookupIndex++)
{
if ((lookupBits[lookupIndex>>5] & (1 << (lookupIndex%32))) == 0)
{
continue;
}
LookupTable lookup = lookupList.Lookup(table,lookupIndex);
ushort lookupType = lookup.LookupType();
ushort subtableCount = lookup.SubTableCount();
bool lookupIsCovered = false;
ushort originalLookupType = lookupType; // We need it to recover,
// if extension lookup updated lookupFormat
for(ushort subtableIndex = 0;
!lookupIsCovered && subtableIndex < subtableCount;
subtableIndex++)
{
lookupType = originalLookupType;
int subtableOffset = lookup.SubtableOffset(table, subtableIndex);
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 singleSub =
new SingleSubstitutionSubtable(subtableOffset);
lookupIsCovered = singleSub.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 2: //MultipleSubst
MultipleSubstitutionSubtable multipleSub =
new MultipleSubstitutionSubtable(subtableOffset);
lookupIsCovered = multipleSub.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 3: //AlternateSubst
AlternateSubstitutionSubtable alternateSub =
new AlternateSubstitutionSubtable(subtableOffset);
lookupIsCovered = alternateSub.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 4: //Ligature subst
LigatureSubstitutionSubtable ligaSub =
new LigatureSubstitutionSubtable(subtableOffset);
lookupIsCovered = ligaSub.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 5: //ContextualSubst
ContextSubtable contextSub =
new ContextSubtable(subtableOffset);
lookupIsCovered = contextSub.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 6: //ChainingSubst
ChainingSubtable chainingSub =
new ChainingSubtable(subtableOffset);
lookupIsCovered = chainingSub.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 7: //Extension lookup
Debug.Assert(false,"Ext.Lookup processed earlier!");
break;
case 8: //ReverseCahiningSubst
ReverseChainingSubtable reverseChainingSub =
new ReverseChainingSubtable(subtableOffset);
lookupIsCovered = reverseChainingSub.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
default:
// Unknown format
lookupIsCovered = true;
break;
}
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);
lookupIsCovered = singlePos.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 2: //PairPos
PairPositioningSubtable pairPos =
new PairPositioningSubtable(subtableOffset);
lookupIsCovered = pairPos.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 3: // CursivePos
// Under construction
CursivePositioningSubtable cursivePositioningSubtable =
new CursivePositioningSubtable(subtableOffset);
lookupIsCovered = cursivePositioningSubtable.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 4: //MarkToBasePos
MarkToBasePositioningSubtable markToBasePos =
new MarkToBasePositioningSubtable(subtableOffset);
lookupIsCovered = markToBasePos.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 5: //MarkToLigaturePos
// Under construction
MarkToLigaturePositioningSubtable markToLigaPos =
new MarkToLigaturePositioningSubtable(subtableOffset);
lookupIsCovered = markToLigaPos.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 6: //MarkToMarkPos
MarkToMarkPositioningSubtable markToMarkPos =
new MarkToMarkPositioningSubtable(subtableOffset);
lookupIsCovered = markToMarkPos.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 7: // Contextual
ContextSubtable contextSub =
new ContextSubtable(subtableOffset);
lookupIsCovered = contextSub.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 8: // Chaining
ChainingSubtable chainingSub =
new ChainingSubtable(subtableOffset);
lookupIsCovered = chainingSub.IsLookupCovered(table,glyphBits,minGlyphId,maxGlyphId);
break;
case 9: //Extension lookup
Debug.Assert(false,"Ext.Lookup processed earlier!");
break;
default:
// Unknown format
lookupIsCovered = true;
break;
}
break;
}
default:
Debug.Assert(false,"Unknown OpenType layout table!");
break;
}
}
if (!lookupIsCovered)
{
// Clean the flag
lookupBits[lookupIndex>>5] &= ~(uint)(1 << (lookupIndex%32));
}
}
// Check if we have any lookup left
bool complexLookupFound = false;
for(int i = 0; i < (lookupCount+31)>>5; i++)
{
if (lookupBits[i] != 0)
{
complexLookupFound = true;
break;
}
}
if (!complexLookupFound)
{
// There are no complex lookups
complexLanguages = null;
complexLanguageCount = 0;
return;
}
// Now go through all langauages and fill the list
complexLanguages = new WritingSystem[10];
complexLanguageCount = 0;
for(ushort scriptIndex = 0; scriptIndex < scriptCount; scriptIndex++)
{
ScriptTable scriptTable = scriptList.GetScriptTable(table, scriptIndex);
uint scriptTag = scriptList.GetScriptTag(table, scriptIndex);
ushort langSysCount = scriptTable.GetLangSysCount(table);
if (scriptTable.IsDefaultLangSysExists(table))
{
AppendLangSys(scriptTag, (uint)OpenTypeTags.dflt,
scriptTable.GetDefaultLangSysTable(table),
featureList,
table,
featureTagsList,
lookupBits,
ref complexLanguages,
ref complexLanguageCount
);
}
for(ushort langSysIndex = 0; langSysIndex < langSysCount; langSysIndex++)
{
uint langSysTag = scriptTable.GetLangSysTag(table, langSysIndex);
AppendLangSys(scriptTag, langSysTag,
scriptTable.GetLangSysTable(table, langSysIndex),
featureList,
table,
featureTagsList,
lookupBits,
ref complexLanguages,
ref complexLanguageCount
);
}
}
}
private static void AppendLangSys(
uint scriptTag,
uint langSysTag,
LangSysTable langSysTable,
FeatureList featureList,
FontTable table,
uint[] featureTagsList,
uint[] lookupBits,
ref WritingSystem[] complexLanguages,
ref int complexLanguageCount
)
{
ushort featureCount = langSysTable.FeatureCount(table);
bool complexFeatureFound = false;
//
for(ushort i = 0; !complexFeatureFound && i < featureCount; i++)
{
ushort featureIndex = langSysTable.GetFeatureIndex(table, i);
uint featureTag = featureList.FeatureTag(table,featureIndex);
bool tagFound = false;
for(int j = 0; !complexFeatureFound && j < featureTagsList.Length; j++)
{
if (featureTagsList[j] == featureTag)
{
tagFound = true;
break;
}
}
if (tagFound)
{
// We should check if any of lookups is complex
FeatureTable featureTable = featureList.FeatureTable(table, featureIndex);
ushort featureLookupCount = featureTable.LookupCount(table);
for(ushort j = 0; j < featureLookupCount; j++)
{
ushort lookupIndex = featureTable.LookupIndex(table, j);
if ((lookupBits[lookupIndex>>5] & (1 << (lookupIndex%32))) != 0)
{
complexFeatureFound = true;
break;
}
}
}
}
if (complexFeatureFound)
{
if (complexLanguages.Length == complexLanguageCount)
{
WritingSystem[] newComplexLanguages =
new WritingSystem[complexLanguages.Length * 3 /2];
for(int i = 0; i < complexLanguages.Length; i++)
{
newComplexLanguages[i] = complexLanguages[i];
}
complexLanguages = newComplexLanguages;
}
complexLanguages[complexLanguageCount].scriptTag = scriptTag;
complexLanguages[complexLanguageCount].langSysTag = langSysTag;
complexLanguageCount++;
}
}