/// <summary>
/// ShaperFeateruList.AddFeature - add a feature to the array
/// </summary>
/// <param name="feature">new feature to add</param>
/// <remarks>
/// This is aimed at allowing shaping engines to add features
/// to the array (generally used for required, all character
/// features added at the start of shaping)
/// </remarks>
internal void AddFeature (Feature feature)
{
if ( _featuresCount == _features.Length )
{
// need more space, so resize the array
if (!Resize((ushort)(_featuresCount + 1),_featuresCount))
{
return; // can't resize array, fail quietly (not going
// to apply this feature!)
}
}
_features[_featuresCount] = feature;
++_featuresCount;
}
/// <summary>
/// ShaperFeateruList.AddFeature - add a feature to the array
/// </summary>
/// <remarks>
/// An alternative to adding an already created feature.
/// </remarks>
internal void AddFeature (ushort startIndex, ushort length, uint featureTag, uint parameter)
{
if ( _featuresCount == _features.Length )
{
// need more space
if (!Resize((ushort)(_featuresCount + 1),_featuresCount))
{
return;
}
}
if (_features[_featuresCount] != null)
{
_features[_featuresCount].Tag = featureTag;
_features[_featuresCount].StartIndex = startIndex;
_features[_featuresCount].Length = length;
_features[_featuresCount].Parameter = parameter;
}
else
{
_features[_featuresCount] = new Feature(startIndex,length,featureTag,parameter);
}
++_featuresCount;
}
/// <summary>
/// ShaperFeateruList.Initialize - initializer for GetGlyphs.
/// </summary>
/// <remarks>
/// Called by pertinent shaper's GetGlyph method (indirectly -
/// this function is actually called by the
/// ShaperBuffers.InitializeFeatureList method which is
/// called by those shapers that need to create a text dependent
/// list of features (e.g. Arabic, Mongolian).
/// </remarks>
internal bool Initialize (ushort newSize)
{
if (_features == null ||
newSize > _features.Length ||
newSize == 0)
{
Feature[] newArray = new Feature[newSize];
if (newArray != null)
{
_features = newArray;
}
}
_featuresCount = 0;
_minimumAddCount = 3; // add space for init,med,final whenever we need to actually resize array
return _features != null;
}
/// <summary>
/// ShaperFeateruList.Resize - used to change the size of the features array
/// </summary>
/// <param name="newSize">Requested new array size</param>
/// <param name="keepCount">number of features to copy into new array</param>
/// <remarks>
/// Used locally for each AddFeature, and by ShaperBuffers.InitializeFeatureList.
/// May be called from a shaping engine.
/// The "keepCount" count takes priority over "newSize" if there's already an
/// array, so if size is less than keep, the resized array has at least keep elements.
/// </remarks>
internal bool Resize (ushort newSize, ushort keepCount)
{
_featuresCount = keepCount; //
if (_features != null &&
_features.Length != 0 &&
keepCount > 0 &&
_features.Length >= keepCount)
{
// make sure keep count is no bigger than current
// array size
ushort currentLength = (ushort)_features.Length;
// make sure new size is at least as big as keep count
if (newSize < keepCount)
{
newSize = keepCount;
}
// if new size is bigger than the current array, create
// a new array
if (newSize > currentLength)
{
// always use minimum leap for adding to array
if (newSize < (currentLength + _minimumAddCount))
{
newSize = (ushort)(currentLength + _minimumAddCount);
}
Feature[] newArray = new Feature[newSize];
if (newArray == null)
{
// can't create new array, leave (at least we still
// have our current array)
return false;
}
// Our client wants us to keep the first "keepCount" entries.
// so copy them now.
for (int i = 0; i < keepCount; ++i)
{
newArray[i] = _features[i];
}
_features = newArray;
}
}
else
{
// nothing to keep, or currently no array so initialize
return Initialize(newSize);
}
return true;
}
private static void GetNextEnabledGlyphRange(
Feature[] FeatureSet, // In: List of features to apply
int featureCount, // In: Actual nubmer of features in FeatureSet
int featureSetOffset, // In: offset of input chars inside feature set
FontTable Table, // Layout table (GSUB or GPOS)
OpenTypeLayoutWorkspace workspace, // workspace with compiled feature set
LangSysTable LangSys, // Language system
FeatureList Features, // List of Features in layout table
ushort lookupIndex, // List of lokups definitions in layout table
int CharCount, // Characters count (i.e. Charmap.Length);
UshortList Charmap, // Character to glyph mapping
int StartChar,
int StartGlyph,
int GlyphRunLength,
out int FirstChar, // First char in enabled range
out int AfterLastChar, // next char after enabled range
out int FirstGlyph, // First char in enabled range
out int AfterLastGlyph, // next char after enabled range
out uint Parameter // applied feature parameter
)
{
FirstChar = int.MaxValue;
AfterLastChar = int.MaxValue;
FirstGlyph = StartGlyph;
AfterLastGlyph = GlyphRunLength;
Parameter = 0;
if (workspace.IsRequiredFeatureFlagSet(lookupIndex))
{
FirstChar = StartChar;
AfterLastChar = CharCount;
FirstGlyph = StartGlyph;
AfterLastGlyph = GlyphRunLength;
return;
}
for(int feature=0; feature < featureCount; feature++)
{
if (!workspace.IsFeatureFlagSet(lookupIndex,feature))
{
continue;
}
Feature featureDescription = FeatureSet[feature];
// Shift values from the feature by specified offset and
// work with these values from here
int featureStart = featureDescription.StartIndex - featureSetOffset;
if (featureStart < 0)
{
featureStart = 0;
}
int featureAfterEnd = featureDescription.StartIndex + featureDescription.Length
- featureSetOffset;
if (featureAfterEnd > CharCount)
{
featureAfterEnd = CharCount;
}
//If feature is disabled there should not be any flag set
Debug.Assert(featureDescription.Parameter != 0);
if (featureAfterEnd <= StartChar)
{
continue;
}
if (featureStart < FirstChar ||
(
featureStart == FirstChar &&
featureAfterEnd >= AfterLastChar
)
)
{
FirstChar = featureStart;
AfterLastChar = featureAfterEnd;
Parameter = featureDescription.Parameter;
continue;
}
}
//No ranges found
if (FirstChar == int.MaxValue)
{
FirstGlyph = GlyphRunLength;
AfterLastGlyph = GlyphRunLength;
}
else
{
if (StartGlyph > Charmap[FirstChar])
FirstGlyph = StartGlyph;
else
FirstGlyph = Charmap[FirstChar];
if (AfterLastChar < CharCount)
AfterLastGlyph = Charmap[AfterLastChar];
else
AfterLastGlyph = GlyphRunLength;
}
}
private static void CompileFeatureSet(
Feature[] FeatureSet, // In: List of features to apply
int featureCount, // In: Actual number of features in FeatureSet
int featureSetOffset, //In: Offset of character input sequence inside feature set
int charCount, // In: number of characters in the input string
FontTable Table, // In: Layout table (GSUB or GPOS)
LangSysTable LangSys, // In: Language system
FeatureList Features, // In: List of Features in layout table
int lookupCount, // In: number of lookup in layout table
OpenTypeLayoutWorkspace workspace // In: workspace with compiled feature set
)
{
workspace.InitLookupUsageFlags(lookupCount, featureCount);
//Set lookup uasge flags for required feature
FeatureTable requiredFeatureTable = LangSys.RequiredFeature(Table, Features);
if (!requiredFeatureTable.IsNull)
{
int featureLookupCount = requiredFeatureTable.LookupCount(Table);
for(ushort lookup = 0; lookup < featureLookupCount; lookup++)
{
workspace.SetRequiredFeatureFlag(requiredFeatureTable.LookupIndex(Table,lookup));
}
}
//Set lookup usage flags for each feature in the FeatureSet
for(int feature = 0; feature < featureCount; feature++)
{
Feature featureDescription = FeatureSet[feature];
//Filter out features which:
// Not enabled or applied completely before or after input characters
if (featureDescription.Parameter == 0 ||
featureDescription.StartIndex >= (featureSetOffset + charCount) ||
(featureDescription.StartIndex+featureDescription.Length) <= featureSetOffset
)
{
continue;
}
FeatureTable featureTable = LangSys.FindFeature( Table,
Features,
featureDescription.Tag);
if (featureTable.IsNull)
{
continue;
}
int featureLookupCount = featureTable.LookupCount(Table);
for(ushort lookup = 0; lookup < featureLookupCount; lookup++)
{
workspace.SetFeatureFlag(featureTable.LookupIndex(Table,lookup), feature);
}
}
}
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);
}
}
}
}
internal static OpenTypeLayoutResult SubstituteGlyphs(
IOpenTypeFont Font, // In: Font access interface
OpenTypeLayoutWorkspace workspace, // In: Workspace for layout engine
uint ScriptTag, // In: Script tag
uint LangSysTag, // In: LangSys tag
Feature[] FeatureSet, // In: List of features to apply
int featureCount, // In: Actual number of features in FeatureSet
int featureSetOffset,
int CharCount, // In: Characters count (i.e. Charmap.Length);
UshortList Charmap, // In/out: Char to glyph mapping
GlyphInfoList Glyphs // In/out: List of GlyphInfo structs
)
{
try
{
FontTable GsubTable = Font.GetFontTable(OpenTypeTags.GSUB);
if (!GsubTable.IsPresent) {return OpenTypeLayoutResult.ScriptNotFound;}
GSUBHeader GsubHeader = new GSUBHeader(0);
ScriptList ScriptList = GsubHeader.GetScriptList(GsubTable);
ScriptTable Script = ScriptList.FindScript(GsubTable,ScriptTag);
if (Script.IsNull) {return OpenTypeLayoutResult.ScriptNotFound;}
LangSysTable LangSys = Script.FindLangSys(GsubTable,LangSysTag);
if (LangSys.IsNull) {return OpenTypeLayoutResult.LangSysNotFound;}
FeatureList FeatureList = GsubHeader.GetFeatureList(GsubTable);
LookupList LookupList = GsubHeader.GetLookupList(GsubTable);
LayoutEngine.ApplyFeatures(
Font,
workspace,
OpenTypeTags.GSUB,
GsubTable,
new LayoutMetrics(), //it is not needed for substitution
LangSys,
FeatureList,
LookupList,
FeatureSet,
featureCount,
featureSetOffset,
CharCount,
Charmap,
Glyphs,
null,
null
);
}
catch (FileFormatException)
{
return OpenTypeLayoutResult.BadFontTable;
}
return OpenTypeLayoutResult.Success;
}
internal static OpenTypeLayoutResult PositionGlyphs(
IOpenTypeFont Font,
OpenTypeLayoutWorkspace workspace,
uint ScriptTag,
uint LangSysTag,
LayoutMetrics Metrics,
Feature[] FeatureSet,
int featureCount,
int featureSetOffset,
int CharCount,
UshortList Charmap,
GlyphInfoList Glyphs,
int* Advances,
LayoutOffset* Offsets
)
{
try
{
FontTable GposTable = Font.GetFontTable(OpenTypeTags.GPOS);
if (!GposTable.IsPresent) {return OpenTypeLayoutResult.ScriptNotFound;}
GPOSHeader GposHeader = new GPOSHeader(0);
ScriptList ScriptList = GposHeader.GetScriptList(GposTable);
ScriptTable Script = ScriptList.FindScript(GposTable,ScriptTag);
if (Script.IsNull) {return OpenTypeLayoutResult.ScriptNotFound;}
LangSysTable LangSys = Script.FindLangSys(GposTable,LangSysTag);
if (LangSys.IsNull) {return OpenTypeLayoutResult.LangSysNotFound;}
FeatureList FeatureList = GposHeader.GetFeatureList(GposTable);
LookupList LookupList = GposHeader.GetLookupList(GposTable);
LayoutEngine.ApplyFeatures(
Font,
workspace,
OpenTypeTags.GPOS,
GposTable,
Metrics,
LangSys,
FeatureList,
LookupList,
FeatureSet,
featureCount,
featureSetOffset,
CharCount,
Charmap,
Glyphs,
Advances,
Offsets
);
}
catch (FileFormatException)
{
return OpenTypeLayoutResult.BadFontTable;
}
return OpenTypeLayoutResult.Success;
}