public static void InitCache(
IOpenTypeFont font,
OpenTypeTags tableTag,
GlyphInfoList glyphInfo,
OpenTypeLayoutWorkspace workspace
)
{
Debug.Assert(tableTag == OpenTypeTags.GSUB || tableTag == OpenTypeTags.GPOS);
byte[] cacheArray = font.GetTableCache(tableTag);
unsafe
{
if (cacheArray == null)
{
workspace.TableCacheData = null;
}
else
{
workspace.TableCacheData = cacheArray;
workspace.AllocateCachePointers(glyphInfo.Length);
RenewPointers(glyphInfo, workspace, 0, glyphInfo.Length);
}
}
}
/// <summary>
/// Reset all structures to the new font/OTTable/script/langsys.
///
/// Client need to call it only once per shaping engine call.
/// This is client's responsibility to ensure that workspace is
/// used for single font/OTTable/script/langsys between Init() calls
/// </summary>
///<param name="font">In: Font access interface</param>
///<param name="tableTag">In: Font table tag</param>
///<param name="scriptTag">In: Script tag</param>
///<param name="langSysTag">In: Language System tag</param>
///<returns>Success if workspace is initialized succesfully, specific error if failed</returns>
internal OpenTypeLayoutResult Init(
IOpenTypeFont font,
OpenTypeTags tableTag,
uint scriptTag,
uint langSysTag
)
{
// Currently all buffers are per call,
// no need to do anything.
return(OpenTypeLayoutResult.Success);
}
private static void CreateTableCache(IOpenTypeFont font, OpenTypeTags tableTag, int maxCacheSize, out int tableCacheSize)
{
// Initialize all computed values
tableCacheSize = 0;
int cacheSize = 0;
int recordCount = 0;
int glyphCount = 0;
int lastLookupAdded = -1;
GlyphLookupRecord[] records = null;
try
{
ComputeTableCache(
font,
tableTag,
maxCacheSize,
ref cacheSize,
ref records,
ref recordCount,
ref glyphCount,
ref lastLookupAdded
);
}
catch (FileFormatException)
{
cacheSize = 0;
}
if (cacheSize > 0)
{
tableCacheSize = FillTableCache(
font,
tableTag,
cacheSize,
records,
recordCount,
glyphCount,
lastLookupAdded
);
}
}
/// <summary>
/// Returns font table data
/// </summary>
public FontTable GetFontTable(OpenTypeTags TableTag)
{
switch (TableTag)
{
case OpenTypeTags.GSUB:
{
return(_gsubTable);
}
case OpenTypeTags.GPOS:
{
return(_gposTable);
}
default:
{
throw new NotSupportedException();
}
}
}
internal byte[] AllocateTableCache(OpenTypeTags tableTag, int size)
{
switch (tableTag)
{
case OpenTypeTags.GSUB:
{
_gsubCache = new byte[size];
return(_gsubCache);
}
case OpenTypeTags.GPOS:
{
_gposCache = new byte[size];
return(_gposCache);
}
default:
{
throw new NotSupportedException();
}
}
}
internal byte[] GetTableCache(OpenTypeTags tableTag)
{
switch (tableTag)
{
case OpenTypeTags.GSUB:
if (Gsub() != null)
{
return(_gsubCache);
}
break;
case OpenTypeTags.GPOS:
if (Gpos() != null)
{
return(_gposCache);
}
break;
default:
throw new NotSupportedException();
}
return(null);
}
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
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
)
{
Invariant.Assert(Format(Table)==3);
NextGlyph = FirstGlyph + 1; //in case we don't match
int glyphCount = GlyphInfo.Length;
int glyphIndex;
ushort backtrackGlyphCount = BacktrackGlyphCount(Table);
ushort inputGlyphCount = InputGlyphCount(Table);
ushort lookaheadGlyphCount = LookaheadGlyphCount(Table);
if (FirstGlyph < backtrackGlyphCount ||
(FirstGlyph + inputGlyphCount) > AfterLastGlyph)
{
return false;
}
bool match = true;
//Check backtrack sequence
glyphIndex = FirstGlyph;
for(ushort backtrackIndex = 0;
backtrackIndex < backtrackGlyphCount && match;
backtrackIndex++)
{
glyphIndex = LayoutEngine.GetNextGlyphInLookup(Font, GlyphInfo,
glyphIndex-1,
LookupFlags,
LayoutEngine.LookBackward
);
if (glyphIndex<0 ||
BacktrackCoverage(Table,backtrackIndex)
.GetGlyphIndex(Table,GlyphInfo.Glyphs[glyphIndex])<0)
{
match=false;
}
}
if (!match) return false;
glyphIndex = FirstGlyph;
for(ushort inputIndex = 0;
inputIndex < inputGlyphCount && match;
inputIndex++)
{
if (glyphIndex>=AfterLastGlyph ||
InputCoverage(Table,inputIndex)
.GetGlyphIndex(Table,GlyphInfo.Glyphs[glyphIndex])<0)
{
match=false;
}
else
{
glyphIndex = LayoutEngine.GetNextGlyphInLookup(Font, GlyphInfo,
glyphIndex + 1,
LookupFlags,
LayoutEngine.LookForward
);
}
}
if (!match) return false;
int afterInputGlyph = glyphIndex; // remember where we were after input seqence
for(ushort lookaheadIndex = 0;
lookaheadIndex < lookaheadGlyphCount && match;
lookaheadIndex++)
{
if (glyphIndex>=GlyphInfo.Length ||
LookaheadCoverage(Table,lookaheadIndex)
.GetGlyphIndex(Table,GlyphInfo.Glyphs[glyphIndex])<0)
{
match=false;
}
else
{
glyphIndex = LayoutEngine.
GetNextGlyphInLookup(Font, GlyphInfo,
glyphIndex + 1,
LookupFlags,
LayoutEngine.LookForward);
}
}
if (match)
{
ContextualLookups(Table).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
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
)
{
Invariant.Assert(Format(Table)==2);
NextGlyph = FirstGlyph + 1; //in case we don't match
int glyphCount = GlyphInfo.Length;
int glyphIndex = FirstGlyph;
ushort glyphId = GlyphInfo.Glyphs[glyphIndex];
if (Coverage(Table).GetGlyphIndex(Table,glyphId) < 0) return false;
ClassDefTable inputClassDef = InputClassDef(Table),
backtrackClassDef = BacktrackClassDef(Table),
lookaheadClassDef = LookaheadClassDef(Table);
ushort GlyphClass = inputClassDef.GetClass(Table,glyphId);
if (GlyphClass >= ClassSetCount(Table)) return false; //!!! Bad font table
SubClassSet subClassSet = ClassSet(Table,GlyphClass);
if (subClassSet.IsNull) return false; // There are no rules for this class
ushort ruleCount = subClassSet.RuleCount(Table);
bool match = false;
for(ushort i=0; !match && i<ruleCount; i++)
{
match = subClassSet.Rule(Table,i).Apply(Font, TableTag, Table, Metrics,
inputClassDef,backtrackClassDef,lookaheadClassDef,
CharCount, Charmap,
GlyphInfo, Advances, Offsets,
LookupFlags, FirstGlyph, 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 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 void ApplyContextualLookups(
IOpenTypeFont Font, // Font access interface
OpenTypeTags TableTag, // Layout table tag (GSUB or GPOS)
FontTable Table, // Layout table (GSUB or GPOS)
LayoutMetrics Metrics, // LayoutMetrics
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
)
{
// Limit nesting level for contextual lookups to
// prevent infinite loops from corrupt fonts
if (nestingLevel >= MaximumContextualLookupNestingLevel)
{
nextGlyph = AfterLastGlyph;
return;
}
LookupList lookupList;
if (TableTag == OpenTypeTags.GSUB)
{
lookupList = (new GSUBHeader(0)).GetLookupList(Table);
}
else
{
lookupList = (new GPOSHeader(0)).GetLookupList(Table);
}
int prevLookupIndex = -1;
int prevSequenceIndex = -1;
while (true)
{
ushort lookupIndex = ushort.MaxValue;
ushort sequenceIndex = ushort.MaxValue;
for(ushort i = 0; i < recordCount; i++)
{
ushort recordLookupIndex = LookupIndex(Table,i);
ushort recordSequenceIndex = SequenceIndex(Table,i);
if (recordLookupIndex < prevLookupIndex ||
(recordLookupIndex == prevLookupIndex &&
recordSequenceIndex <= prevSequenceIndex
)
)
{
// This record we already should have been processed
continue;
}
// Among not proccessed record, find next one
if ( recordLookupIndex < lookupIndex ||
(recordLookupIndex == lookupIndex &&
recordSequenceIndex < sequenceIndex
)
)
{
lookupIndex = recordLookupIndex;
sequenceIndex = recordSequenceIndex;
}
}
if (lookupIndex == ushort.MaxValue)
{
// All records processed (or we had duplicate records, which we skipped automatically)
break;
}
//remember for the next iteration
prevLookupIndex = lookupIndex;
prevSequenceIndex = sequenceIndex;
// Now find actual glyph where to apply lookup (may depend on lookup flags)
int recordFirstGlyph = FirstGlyph;
for (int i = 0; i < sequenceIndex && recordFirstGlyph < AfterLastGlyph; i++)
{
recordFirstGlyph = LayoutEngine.GetNextGlyphInLookup(Font, GlyphInfo,
recordFirstGlyph + 1,
LookupFlags,
LayoutEngine.LookForward
);
}
if (recordFirstGlyph >= AfterLastGlyph)
{
// Requested position is outside of input sequence, do nothing.
continue;
}
// And finally apply lookup
int prevLength = GlyphInfo.Length;
int dummyNextGlyph;
LayoutEngine.ApplyLookup(
Font,
TableTag,
Table,
Metrics,
lookupList.Lookup(Table, lookupIndex),
CharCount,
Charmap,
GlyphInfo,
Advances,
Offsets,
recordFirstGlyph,
AfterLastGlyph,
Parameter,
nestingLevel + 1,
out dummyNextGlyph // we don't need it here
);
//We need to adjust afterLastGlyph, in case non-single substitution happened
AfterLastGlyph += GlyphInfo.Length - prevLength;
}
nextGlyph = AfterLastGlyph;
}
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
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
)
{
Invariant.Assert(Format(Table)==1);
NextGlyph = FirstGlyph + 1; //in case we don't match
int glyphCount = GlyphInfo.Length;
int glyphIndex = FirstGlyph;
ushort glyphId = GlyphInfo.Glyphs[glyphIndex];
int coverageIndex = Coverage(Table).GetGlyphIndex(Table,glyphId);
if (coverageIndex < 0) return false;
SubRuleSet subRuleSet= RuleSet(Table, coverageIndex);
ushort ruleCount = subRuleSet.RuleCount(Table);
bool match = false;
for(ushort i=0; !match && i<ruleCount; i++)
{
match = subRuleSet.Rule(Table,i).Apply(Font, TableTag, Table, Metrics,
CharCount, Charmap,
GlyphInfo, Advances, Offsets,
LookupFlags, FirstGlyph, AfterLastGlyph,
Parameter,
nestingLevel,
out NextGlyph
);
}
return match;
}
private static bool IsLookupReversal(OpenTypeTags TableTag, ushort LookupType)
{
return (TableTag == OpenTypeTags.GSUB && LookupType == 8);
}
private static int FillTableCache(
IOpenTypeFont font,
OpenTypeTags tableTag,
int cacheSize,
GlyphLookupRecord[] records,
int recordCount,
int glyphCount,
int lastLookupAdded
)
{
// Fill the cache.
// We are using basically the same code to fill the cache
// that had been used to calculate the size. So pList pointer
// moving through cache memory should not overrun allocated space.
// Asserts are set to chek that at every place where we write to cache
// and at the end where we check that we filled exactly the same amount.
unsafe
{
byte[] cache = font.AllocateTableCache(tableTag, cacheSize);
if (cache == null)
{
// We failed to allocate cache of requested size,
// exit without created cache.
return(0);
}
fixed(byte *pCacheByte = &cache[0])
{
ushort *pCache = (ushort *)pCacheByte;
pCache[0] = (ushort)cacheSize; // Cache size
pCache[1] = 0xFFFF; // 0xFFFF constants
pCache[2] = (ushort)(lastLookupAdded + 1); // Number of lookups that fit into the cache
pCache[3] = (ushort)glyphCount; // Glyph count
ushort *pGlyphs = pCache + 4;
ushort *pList = pGlyphs + glyphCount * 2;
ushort *pPrevList = null;
int prevListIndex = -1, prevListLength = 0;
int curListIndex = 0, curListLength = 1;
ushort curGlyph = records[0].Glyph;
for (int i = 1; i < recordCount; i++)
{
if (records[i].Glyph != curGlyph)
{
// We've found another list. Compare it with previous
if (prevListLength != curListLength || // Fast check to avoid full comparison
!CompareGlyphRecordLists(records,
recordCount,
prevListIndex,
curListIndex)
)
{
// New list. Remember position in pPrevList and write list down
pPrevList = pList;
for (int j = curListIndex; j < i; j++)
{
Debug.Assert((pList - pCache) * sizeof(ushort) < cacheSize);
*pList = records[j].Lookup;
pList++;
}
Debug.Assert((pList - pCache) * sizeof(ushort) < cacheSize);
*pList = 0xFFFF;
pList++;
}
// Now pPrevList points at the first element of the correct list.
*pGlyphs = curGlyph; // Write down glyph id
pGlyphs++;
*pGlyphs = (ushort)((pPrevList - pCache) * sizeof(ushort)); // Write down list offset
pGlyphs++;
prevListIndex = curListIndex;
prevListLength = curListLength;
curGlyph = records[i].Glyph;
curListIndex = i;
curListLength = 1;
}
}
// And we need to check the last list we missed in the loop
if (prevListLength != curListLength || // Fast check to avoid full comparison
!CompareGlyphRecordLists(records,
recordCount,
prevListIndex,
curListIndex)
)
{
// New list. Remember position in pPrevList and write list down
pPrevList = pList;
for (int j = curListIndex; j < recordCount; j++)
{
Debug.Assert((pList - pCache) * sizeof(ushort) < cacheSize);
*pList = records[j].Lookup;
pList++;
}
Debug.Assert((pList - pCache) * sizeof(ushort) < cacheSize);
*pList = 0xFFFF;
pList++;
}
// Now pPrevList points at the first element of the correct list.
*pGlyphs = curGlyph; // Write down glyph id
pGlyphs++;
*pGlyphs = (ushort)((pPrevList - pCache) * sizeof(ushort)); // Write down list offset
pGlyphs++;
// We are done with the cache
Debug.Assert((pList - pCache) * sizeof(ushort) == cacheSize); // We exactly filled up the cache
Debug.Assert((pGlyphs - pCache) * sizeof(ushort) == (4 + glyphCount * 2) * sizeof(ushort)); // Glyphs ended where lists start.
}
}
return(cacheSize);
}
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;
}
public byte[] AllocateTableCache(OpenTypeTags tableTag, int size)
{
return(_layout.AllocateTableCache(tableTag, size));
}
public byte[] GetTableCache(OpenTypeTags tableTag)
{
return(_layout.GetTableCache(tableTag));
}
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 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);
}
private static void ComputeTableCache(
IOpenTypeFont font,
OpenTypeTags tableTag,
int maxCacheSize,
ref int cacheSize,
ref GlyphLookupRecord[] records,
ref int recordCount,
ref int glyphCount,
ref int lastLookupAdded
)
{
FontTable table = font.GetFontTable(tableTag);
if (!table.IsPresent)
{
return;
}
FeatureList featureList;
LookupList lookupList;
Debug.Assert(tableTag == OpenTypeTags.GSUB || tableTag == OpenTypeTags.GPOS);
switch (tableTag)
{
case OpenTypeTags.GSUB:
{
GSUBHeader header = new GSUBHeader();
featureList = header.GetFeatureList(table);
lookupList = header.GetLookupList(table);
break;
}
case OpenTypeTags.GPOS:
{
GPOSHeader header = new GPOSHeader();
featureList = header.GetFeatureList(table);
lookupList = header.GetLookupList(table);
break;
}
default:
{
Debug.Assert(false);
featureList = new FeatureList(0);
lookupList = new LookupList(0);
break;
}
}
// Estimate number of records that can fit into cache using ratio of approximately
// 4 bytes of cache per actual record. Most of fonts will fit into this value, except
// some tiny caches and big EA font that can have ratio of around 5 (theoretical maximum is 8).
//
// If actual ratio for particluar font will be larger than 4, we will remove records
// from the end to fit into cache.
//
// If ratio is less than 4 we actually can fit more lookups, but for the speed and because most fonts
// will fit into cache completely anyway we do not do anything about this here.
int maxRecordCount = maxCacheSize / 4;
// For now, we will just allocate array of maximum size.
// Given heuristics above, it wont be greater than max cache size.
//
records = new GlyphLookupRecord[maxRecordCount];
//
// Now iterate through lookups and subtables, filling in lookup-glyph pairs list
//
int lookupCount = lookupList.LookupCount(table);
int recordCountAfterLastLookup = 0;
//
// Not all lookups can be invoked from feature directly,
// they are actions from contextual lookups.
// We are not interested in those, because they will
// never work from high level, so do not bother adding them to the cache.
//
// Filling array of lookup usage bits, to skip those not mapped to any lookup
//
BitArray lookupUsage = new BitArray(lookupCount);
for (ushort feature = 0; feature < featureList.FeatureCount(table); feature++)
{
FeatureTable featureTable = featureList.FeatureTable(table, feature);
for (ushort lookup = 0; lookup < featureTable.LookupCount(table); lookup++)
{
ushort lookupIndex = featureTable.LookupIndex(table, lookup);
if (lookupIndex >= lookupCount)
{
// This must be an invalid font. Just igonoring this lookup here.
continue;
}
lookupUsage[lookupIndex] = true;
}
}
// Done with lookup usage bits
for (ushort lookupIndex = 0; lookupIndex < lookupCount; lookupIndex++)
{
if (!lookupUsage[lookupIndex])
{
continue;
}
int firstLookupRecord = recordCount;
int maxLookupGlyph = -1;
bool cacheIsFull = false;
LookupTable lookup = lookupList.Lookup(table, lookupIndex);
ushort lookupType = lookup.LookupType();
ushort subtableCount = lookup.SubTableCount();
for (ushort subtableIndex = 0; subtableIndex < subtableCount; subtableIndex++)
{
int subtableOffset = lookup.SubtableOffset(table, subtableIndex);
CoverageTable coverage = GetSubtablePrincipalCoverage(table, tableTag, lookupType, subtableOffset);
if (coverage.IsInvalid)
{
continue;
}
cacheIsFull = !AppendCoverageGlyphRecords(table, lookupIndex, coverage, records, ref recordCount, ref maxLookupGlyph);
if (cacheIsFull)
{
break;
}
}
if (cacheIsFull)
{
break;
}
lastLookupAdded = lookupIndex;
recordCountAfterLastLookup = recordCount;
}
// We may hit storage overflow in the middle of lookup. Throw this partial lookup away
recordCount = recordCountAfterLastLookup;
if (lastLookupAdded == -1)
{
// We did not succeed adding even single lookup.
return;
}
// We now have glyph records for (may be not all) lookups in the table.
// Cache structures should be sorted by glyph, then by lookup index.
Array.Sort(records, 0, recordCount);
cacheSize = -1;
glyphCount = -1;
// It may happen, that records do not fit into cache, even using our heuristics.
// We will remove lookups one by one from the end until it fits.
while (recordCount > 0)
{
CalculateCacheSize(records, recordCount, out cacheSize, out glyphCount);
if (cacheSize <= maxCacheSize)
{
// Fine, we now fit into max cache size
break;
}
else
{
// Find last lookup index
int lastLookup = -1;
for (int i = 0; i < recordCount; i++)
{
int lookup = records[i].Lookup;
if (lastLookup < lookup)
{
lastLookup = lookup;
}
}
Debug.Assert(lastLookup >= 0); // There are lookups, so there was an index
// Remove it
int currentRecord = 0;
for (int i = 0; i < recordCount; i++)
{
if (records[i].Lookup == lastLookup)
{
continue;
}
if (currentRecord == i)
{
continue;
}
records[currentRecord] = records[i];
currentRecord++;
}
recordCount = currentRecord;
// Do not forget update lastLookupAdded variable
lastLookupAdded = lastLookup - 1;
}
}
if (recordCount == 0)
{
// We can't fit even single lookup into the cache
return;
}
Debug.Assert(cacheSize > 0); // We've calcucalted them at least ones, and
Debug.Assert(glyphCount > 0); // if there is no records, we already should've exited
}
internal static bool ApplyLookup(
IOpenTypeFont Font, // Font access interface
OpenTypeTags TableTag, // Layout table tag (GSUB or GPOS)
FontTable Table, // Layout table (GSUB or GPOS)
LayoutMetrics Metrics, // LayoutMetrics
LookupTable Lookup, // List definition structure
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
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
)
{
Debug.Assert(TableTag==OpenTypeTags.GSUB || TableTag==OpenTypeTags.GPOS);
Debug.Assert(FirstGlyph<AfterLastGlyph);
Debug.Assert(AfterLastGlyph<=GlyphInfo.Length);
ushort lookupType = Lookup.LookupType();
ushort lookupFlags = Lookup.LookupFlags();
ushort subtableCount = Lookup.SubTableCount();
bool match=false;
NextGlyph=FirstGlyph+1; //Just to avoid compiler error
// Find first glyph
if (!IsLookupReversal(TableTag,lookupType))
{
FirstGlyph=LayoutEngine.GetNextGlyphInLookup(Font,GlyphInfo,FirstGlyph,
lookupFlags,LayoutEngine.LookForward);
}
else
{
AfterLastGlyph = LayoutEngine.GetNextGlyphInLookup(Font,GlyphInfo,AfterLastGlyph-1,
lookupFlags,LayoutEngine.LookBackward) + 1;
}
if (FirstGlyph>=AfterLastGlyph) return match;
ushort originalLookupType = lookupType; // We need it to recover, if extension lookup updated lookupFormat
for(ushort subtableIndex=0; !match && 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);
match = singleSub.Apply( Table,
GlyphInfo,
FirstGlyph,
out NextGlyph
);
break;
case 2: //MultipleSubst
MultipleSubstitutionSubtable multipleSub =
new MultipleSubstitutionSubtable(subtableOffset);
match = multipleSub.Apply( Font,
Table,
CharCount,
Charmap,
GlyphInfo,
lookupFlags,
FirstGlyph,
AfterLastGlyph,
out NextGlyph
);
break;
case 3: //AlternateSubst
AlternateSubstitutionSubtable alternateSub =
new AlternateSubstitutionSubtable(subtableOffset);
match = alternateSub.Apply( Table,
GlyphInfo,
Parameter,
FirstGlyph,
out NextGlyph
);
break;
case 4: //Ligature subst
LigatureSubstitutionSubtable ligaSub =
new LigatureSubstitutionSubtable(subtableOffset);
match = ligaSub.Apply( Font,
Table,
CharCount,
Charmap,
GlyphInfo,
lookupFlags,
FirstGlyph,
AfterLastGlyph,
out NextGlyph
);
break;
case 5: //ContextualSubst
ContextSubtable contextSub =
new ContextSubtable(subtableOffset);
match = contextSub.Apply( Font,
TableTag,
Table,
Metrics,
CharCount,
Charmap,
GlyphInfo,
Advances,
Offsets,
lookupFlags,
FirstGlyph,
AfterLastGlyph,
Parameter,
nestingLevel,
out NextGlyph
);
break;
case 6: //ChainingSubst
ChainingSubtable chainingSub =
new ChainingSubtable(subtableOffset);
match = chainingSub.Apply( Font,
TableTag,
Table,
Metrics,
CharCount,
Charmap,
GlyphInfo,
Advances,
Offsets,
lookupFlags,
FirstGlyph,
AfterLastGlyph,
Parameter,
nestingLevel,
out NextGlyph
);
break;
case 7: //Extension lookup
// Ext.Lookup processed earlier. It can't contain another ext.lookups in it.
// Just skip it (do nothing);
NextGlyph = FirstGlyph + 1;
break;
case 8: //ReverseCahiningSubst
ReverseChainingSubtable reverseChainingSub =
new ReverseChainingSubtable(subtableOffset);
match = reverseChainingSub.Apply(
Font,
TableTag,
Table,
Metrics,
CharCount,
Charmap,
GlyphInfo,
Advances,
Offsets,
lookupFlags,
FirstGlyph,
AfterLastGlyph,
Parameter,
out NextGlyph
);
break;
default:
// Unknown format
NextGlyph = FirstGlyph+1;
break;
}
if (match)
{
if (!IsLookupReversal(TableTag,lookupType))
{
UpdateGlyphFlags(Font,GlyphInfo,FirstGlyph,NextGlyph,true,GlyphFlags.Substituted);
}
else
{
UpdateGlyphFlags(Font,GlyphInfo,NextGlyph,AfterLastGlyph,true,GlyphFlags.Substituted);
}
}
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);
match = singlePos.Apply(Table,
Metrics,
GlyphInfo,
Advances,
Offsets,
FirstGlyph,
AfterLastGlyph,
out NextGlyph
);
break;
case 2: //PairPos
PairPositioningSubtable pairPos =
new PairPositioningSubtable(subtableOffset);
match = pairPos.Apply( Font,
Table,
Metrics, // LayoutMetrics
GlyphInfo, // List of GlyphInfo structs
lookupFlags, // Lookup flags for glyph lookups
Advances, // Glyph adv.widths
Offsets, // Glyph offsets
FirstGlyph, // where to apply lookup
AfterLastGlyph, // how long is a context we can use
out NextGlyph // Next glyph to process
);
break;
case 3: // CursivePos
// Under construction
CursivePositioningSubtable cursivePositioningSubtable =
new CursivePositioningSubtable(subtableOffset);
cursivePositioningSubtable.Apply( Font,
Table,
Metrics, // LayoutMetrics
GlyphInfo, // List of GlyphInfo structs
lookupFlags, // Lookup flags for glyph lookups
Advances, // Glyph adv.widths
Offsets, // Glyph offsets
FirstGlyph, // where to apply lookup
AfterLastGlyph, // how long is a context we can use
out NextGlyph // Next glyph to process
);
break;
case 4: //MarkToBasePos
MarkToBasePositioningSubtable markToBasePos =
new MarkToBasePositioningSubtable(subtableOffset);
match = markToBasePos.Apply(Font,
Table,
Metrics, // LayoutMetrics
GlyphInfo, // List of GlyphInfo structs
lookupFlags, // Lookup flags for glyph lookups
Advances, // Glyph adv.widths
Offsets, // Glyph offsets
FirstGlyph, // where to apply lookup
AfterLastGlyph, // how long is a context we can use
out NextGlyph // Next glyph to process
);
break;
case 5: //MarkToLigaturePos
// Under construction
MarkToLigaturePositioningSubtable markToLigaPos =
new MarkToLigaturePositioningSubtable(subtableOffset);
match = markToLigaPos.Apply(
Font,
Table,
Metrics, // LayoutMetrics
GlyphInfo, // List of GlyphInfo structs
lookupFlags, // Lookup flags for glyph lookups
CharCount, // Characters count (i.e. Charmap.Length);
Charmap, // Char to glyph mapping
Advances, // Glyph adv.widths
Offsets, // Glyph offsets
FirstGlyph, // where to apply lookup
AfterLastGlyph, // how long is a context we can use
out NextGlyph // Next glyph to process
);
break;
case 6: //MarkToMarkPos
MarkToMarkPositioningSubtable markToMarkPos =
new MarkToMarkPositioningSubtable(subtableOffset);
match = markToMarkPos.Apply(
Font,
Table,
Metrics, // LayoutMetrics
GlyphInfo, // List of GlyphInfo structs
lookupFlags, // Lookup flags for glyph lookups
Advances, // Glyph adv.widths
Offsets, // Glyph offsets
FirstGlyph, // where to apply lookup
AfterLastGlyph, // how long is a context we can use
out NextGlyph // Next glyph to process
);
break;
case 7: // Contextual
ContextSubtable contextSub =
new ContextSubtable(subtableOffset);
match = contextSub.Apply( Font,
TableTag,
Table,
Metrics,
CharCount,
Charmap,
GlyphInfo,
Advances,
Offsets,
lookupFlags,
FirstGlyph,
AfterLastGlyph,
Parameter,
nestingLevel,
out NextGlyph
);
break;
case 8: // Chaining
ChainingSubtable chainingSub =
new ChainingSubtable(subtableOffset);
match = chainingSub.Apply( Font,
TableTag,
Table,
Metrics,
CharCount,
Charmap,
GlyphInfo,
Advances,
Offsets,
lookupFlags,
FirstGlyph,
AfterLastGlyph,
Parameter,
nestingLevel,
out NextGlyph
);
break;
case 9: //Extension lookup
// Ext.Lookup processed earlier. It can't contain another ext.lookups in it.
// Just skip it (do nothing);
NextGlyph = FirstGlyph + 1;
break;
default:
// Unknown format
NextGlyph = FirstGlyph + 1;
break;
}
if (match)
{
UpdateGlyphFlags(Font,GlyphInfo,FirstGlyph,NextGlyph,false,GlyphFlags.Positioned);
}
break;
}
default:
Debug.Assert(false,"Unknown OpenType layout table!");
break;
}
}
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
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
)
{
switch (Format(Table))
{
case 1:
GlyphContextSubtable glyphContextSubtable =
new GlyphContextSubtable(offset);
return glyphContextSubtable.Apply(
Font, TableTag, Table, Metrics,
CharCount, Charmap,
GlyphInfo, Advances, Offsets,
LookupFlags, FirstGlyph, AfterLastGlyph,
Parameter,
nestingLevel,
out NextGlyph
);
case 2:
ClassContextSubtable classContextSubtable =
new ClassContextSubtable(offset);
return classContextSubtable.Apply(
Font, TableTag, Table, Metrics,
CharCount, Charmap,
GlyphInfo, Advances, Offsets,
LookupFlags, FirstGlyph, AfterLastGlyph,
Parameter,
nestingLevel,
out NextGlyph
);
case 3:
CoverageContextSubtable coverageContextSubtable =
new CoverageContextSubtable(offset);
return coverageContextSubtable.Apply(
Font, TableTag, Table, Metrics,
CharCount, Charmap,
GlyphInfo, Advances, Offsets,
LookupFlags, FirstGlyph, AfterLastGlyph,
Parameter,
nestingLevel,
out NextGlyph
);
default:
//Unknown format
NextGlyph = FirstGlyph+1; //don't match
return false;
}
}
public static void ApplyFeatures(
IOpenTypeFont Font,
OpenTypeLayoutWorkspace workspace,
OpenTypeTags TableTag,
FontTable Table,
LayoutMetrics Metrics,
LangSysTable LangSys,
FeatureList Features,
LookupList Lookups,
Feature[] FeatureSet,
int featureCount,
int featureSetOffset,
int CharCount,
UshortList Charmap,
GlyphInfoList GlyphInfo,
int* Advances,
LayoutOffset* Offsets
)
{
UpdateGlyphFlags(Font, GlyphInfo, 0, GlyphInfo.Length, false, GlyphFlags.NotChanged);
// if client did not supply us with workspace
// we will create our own (temporarily)
if (workspace == null)
{
workspace = new OpenTypeLayoutWorkspace();
}
ushort lookupCount=Lookups.LookupCount(Table);
//Compile feature set
CompileFeatureSet(
FeatureSet,
featureCount,
featureSetOffset,
CharCount,
Table,
LangSys,
Features,
lookupCount,
workspace
);
OpenTypeLayoutCache.InitCache(Font, TableTag, GlyphInfo, workspace);
for(ushort lookupIndex = 0; lookupIndex < lookupCount; lookupIndex++)
{
if (!workspace.IsAggregatedFlagSet(lookupIndex))
{
continue;
}
int firstChar=0,
afterLastChar=0,
firstGlyph=0,
afterLastGlyph=0;
OpenTypeLayoutCache.FindNextLookup(workspace,
GlyphInfo,
lookupIndex,
out lookupIndex,
out firstGlyph);
// We need to check this again, because FindNextLookup will change lookupIndex
if (lookupIndex >= lookupCount)
{
break;
}
if (!workspace.IsAggregatedFlagSet(lookupIndex))
{
continue;
}
LookupTable lookup = Lookups.Lookup(Table, lookupIndex);
uint parameter=0;
bool isLookupReversal = IsLookupReversal(TableTag, lookup.LookupType());
while(firstGlyph < GlyphInfo.Length) // While we have ranges to work on
{
if (!OpenTypeLayoutCache.FindNextGlyphInLookup(workspace, lookupIndex, isLookupReversal, ref firstGlyph, ref afterLastGlyph))
{
firstGlyph = afterLastGlyph;
}
if (firstGlyph < afterLastGlyph) // Apply lookup while in one range
{
int nextGlyph;
int oldLength = GlyphInfo.Length;
int glyphsAfterLastChar = oldLength - afterLastGlyph;
bool match = ApplyLookup(
Font, // In: Font access interface
TableTag, // Layout table tag (GSUB or GPOS)
Table, // Layout table (GSUB or GPOS)
Metrics, // In: LayoutMetrics
lookup, // Lookup definition structure
CharCount,
Charmap, // In: Char to glyph mapping
GlyphInfo, // In/out: List of GlyphInfo structs
Advances, // In/out: Glyph adv.widths
Offsets, // In/out: Glyph offsets
firstGlyph, // where to apply it
afterLastGlyph, // how long is a context we can use
parameter, // lookup parameter
0, // Nesting level for contextual lookups
out nextGlyph // out: next glyph index
// !!!: for reversal lookup, should
// return new afterLastGlyph
);
if (match)
{
//Adjust range end if length changed,
// for reversal changes happens beyond afterLast, no change needed
if (!isLookupReversal)
{
OpenTypeLayoutCache.OnGlyphsChanged(workspace, GlyphInfo, oldLength, firstGlyph, nextGlyph);
afterLastGlyph = GlyphInfo.Length - glyphsAfterLastChar;
firstGlyph = nextGlyph;
}
else
{
OpenTypeLayoutCache.OnGlyphsChanged(workspace, GlyphInfo, oldLength, nextGlyph, afterLastGlyph);
afterLastGlyph = nextGlyph;
}
}
else
{
if (isLookupReversal)
afterLastGlyph = nextGlyph;
else
firstGlyph = nextGlyph;
}
}
else // End of range. Get next
{
GetNextEnabledGlyphRange(
FeatureSet,
featureCount,
featureSetOffset,
Table,
workspace,
LangSys,
Features,
lookupIndex,
CharCount,
Charmap,
afterLastChar,
afterLastGlyph,
GlyphInfo.Length,
out firstChar,
out afterLastChar,
out firstGlyph,
out afterLastGlyph,
out parameter);
}
}
}
}
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
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
out int NextGlyph // out: next glyph index
)
{
//This will be the next glyph, does not matter sequence matched or not
NextGlyph = AfterLastGlyph-1;
if (Format(Table)!=1) return false; //Unknown
bool match = true;
int inputGlyphIndex = AfterLastGlyph - 1;
int glyphIndex;
//Check input glyph
int coverageIndex = InputCoverage(Table).GetGlyphIndex(Table,GlyphInfo.Glyphs[inputGlyphIndex]);
if (coverageIndex<0) return false;
//we reading data sequenctially from table, moving pointer through it
int curOffset = offset + offsetBacktrackGlyphCount;
//
// Check backtrack sequence
//
ushort backtrackGlyphCount = GlyphCount(Table,curOffset);
curOffset += sizeCount;
glyphIndex = inputGlyphIndex;
for(ushort backtrackIndex = 0;
backtrackIndex < backtrackGlyphCount && match;
backtrackIndex++)
{
glyphIndex = LayoutEngine.GetNextGlyphInLookup(Font, GlyphInfo,
glyphIndex-1,
LookupFlags,
LayoutEngine.LookBackward
);
if (glyphIndex<0)
{
match = false;
}
else
{
match = (Coverage(Table,curOffset).GetGlyphIndex(Table,GlyphInfo.Glyphs[glyphIndex]) >= 0);
curOffset += sizeOffset;
}
}
ushort lookaheadGlyphCount = GlyphCount(Table,curOffset);
curOffset += sizeCount;
glyphIndex = inputGlyphIndex;
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
{
match = (Coverage(Table,curOffset).GetGlyphIndex(Table,GlyphInfo.Glyphs[glyphIndex]) >= 0);
curOffset += sizeOffset;
}
}
if (match)
{
curOffset += sizeCount + sizeGlyphId*coverageIndex;
GlyphInfo.Glyphs[inputGlyphIndex] = Glyph(Table,curOffset);
GlyphInfo.GlyphFlags[inputGlyphIndex] = (ushort)(GlyphFlags.Unresolved | GlyphFlags.Substituted);
}
return match;
}
/// <summary>
/// Reset all structures to the new font/OTTable/script/langsys.
///
/// Client need to call it only once per shaping engine call.
/// This is client's responsibility to ensure that workspace is
/// used for single font/OTTable/script/langsys between Init() calls
/// </summary>
///<param name="font">In: Font access interface</param>
///<param name="tableTag">In: Font table tag</param>
///<param name="scriptTag">In: Script tag</param>
///<param name="langSysTag">In: Language System tag</param>
///<returns>Success if workspace is initialized succesfully, specific error if failed</returns>
internal OpenTypeLayoutResult Init(
IOpenTypeFont font,
OpenTypeTags tableTag,
uint scriptTag,
uint langSysTag
)
{
// Currently all buffers are per call,
// no need to do anything.
return OpenTypeLayoutResult.Success;
}
