Package org.apache.fontbox.ttf

Class GlyphSubstitutionTable

java.lang.Object

org.apache.fontbox.ttf.TTFTable

org.apache.fontbox.ttf.GlyphSubstitutionTable

public class GlyphSubstitutionTable
extends TTFTable

A glyph substitution 'GSUB' table in a TrueType or OpenType font.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
(package private) static class	GlyphSubstitutionTable.CoverageTable
(package private) static class	GlyphSubstitutionTable.CoverageTableFormat1
(package private) static class	GlyphSubstitutionTable.CoverageTableFormat2
(package private) static class	GlyphSubstitutionTable.FeatureRecord
(package private) static class	GlyphSubstitutionTable.FeatureTable
(package private) static class	GlyphSubstitutionTable.LangSysRecord
(package private) static class	GlyphSubstitutionTable.LangSysTable
(package private) static class	GlyphSubstitutionTable.LookupSubTable
(package private) static class	GlyphSubstitutionTable.LookupTable
(package private) static class	GlyphSubstitutionTable.LookupTypeSingleSubstFormat1
(package private) static class	GlyphSubstitutionTable.LookupTypeSingleSubstFormat2
(package private) static class	GlyphSubstitutionTable.RangeRecord
(package private) static class	GlyphSubstitutionTable.ScriptRecord
(package private) static class	GlyphSubstitutionTable.ScriptTable

Field Summary

Fields

Modifier and Type	Field	Description
private GlyphSubstitutionTable.FeatureRecord[]	featureList
private String	lastUsedSupportedScript
private static final org.apache.commons.logging.Log	LOG
private final Map<Integer,Integer>	lookupCache
private GlyphSubstitutionTable.LookupTable[]	lookupList
private final Map<Integer,Integer>	reverseLookup
private LinkedHashMap<String,GlyphSubstitutionTable.ScriptTable>	scriptList
static final String	TAG

Fields inherited from class org.apache.fontbox.ttf.TTFTable

font, initialized

Constructor Summary

Constructors

Constructor	Description
GlyphSubstitutionTable(TrueTypeFont font)

Method Summary

Modifier and Type	Method	Description
private int	applyFeature(GlyphSubstitutionTable.FeatureRecord featureRecord, int gid)
private boolean	containsFeature(List<GlyphSubstitutionTable.FeatureRecord> featureRecords, String featureTag)
private int	doLookup(GlyphSubstitutionTable.LookupTable lookupTable, int gid)
private List<GlyphSubstitutionTable.FeatureRecord>	getFeatureRecords(Collection<GlyphSubstitutionTable.LangSysTable> langSysTables, List<String> enabledFeatures)	Get a list of FeatureRecords from a collection of LangSysTables.
private Collection<GlyphSubstitutionTable.LangSysTable>	getLangSysTables(String scriptTag)
int	getSubstitution(int gid, String[] scriptTags, List<String> enabledFeatures)	Apply glyph substitutions to the supplied gid.
int	getUnsubstitution(int sgid)	For a substitute-gid (obtained from getSubstitution(int, String[], List)), retrieve the original gid.
(package private) void	read(TrueTypeFont ttf, TTFDataStream data)	This will read the required data from the stream.
(package private) GlyphSubstitutionTable.CoverageTable	readCoverageTable(TTFDataStream data, long offset)
(package private) GlyphSubstitutionTable.FeatureRecord[]	readFeatureList(TTFDataStream data, long offset)
(package private) GlyphSubstitutionTable.FeatureTable	readFeatureTable(TTFDataStream data, long offset)
(package private) GlyphSubstitutionTable.LangSysTable	readLangSysTable(TTFDataStream data, long offset)
(package private) GlyphSubstitutionTable.LookupTable[]	readLookupList(TTFDataStream data, long offset)
(package private) GlyphSubstitutionTable.LookupSubTable	readLookupSubTable(TTFDataStream data, long offset)
(package private) GlyphSubstitutionTable.LookupTable	readLookupTable(TTFDataStream data, long offset)
(package private) GlyphSubstitutionTable.RangeRecord	readRangeRecord(TTFDataStream data)
(package private) LinkedHashMap<String,GlyphSubstitutionTable.ScriptTable>	readScriptList(TTFDataStream data, long offset)
(package private) GlyphSubstitutionTable.ScriptTable	readScriptTable(TTFDataStream data, long offset)
private void	removeFeature(List<GlyphSubstitutionTable.FeatureRecord> featureRecords, String featureTag)
private String	selectScriptTag(String[] tags)	Choose from one of the supplied OpenType script tags, depending on what the font supports and potentially on context.

Methods inherited from class org.apache.fontbox.ttf.TTFTable

getCheckSum, getInitialized, getLength, getOffset, getTag, setCheckSum, setLength, setOffset, setTag

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

LOG

private static final org.apache.commons.logging.Log LOG

TAG

public static final String TAG

See Also:

• Constant Field Values

scriptList

private LinkedHashMap<String,GlyphSubstitutionTable.ScriptTable> scriptList

featureList

private GlyphSubstitutionTable.FeatureRecord[] featureList

lookupList

private GlyphSubstitutionTable.LookupTable[] lookupList

lookupCache

private final Map<Integer,Integer> lookupCache

reverseLookup

private final Map<Integer,Integer> reverseLookup

lastUsedSupportedScript

private String lastUsedSupportedScript

Constructor Details

GlyphSubstitutionTable

GlyphSubstitutionTable(TrueTypeFont font)

Method Details

read

void read(TrueTypeFont ttf,
 TTFDataStream data)
   throws IOException

Description copied from class: TTFTable

This will read the required data from the stream.

Overrides:

read in class TTFTable

Parameters:

ttf - The font that is being read.

data - The stream to read the data from.

Throws:

IOException - If there is an error reading the data.

readScriptList

LinkedHashMap<String,GlyphSubstitutionTable.ScriptTable> readScriptList(TTFDataStream data,
 long offset)
                                                                 throws IOException

Throws:

IOException

readScriptTable

GlyphSubstitutionTable.ScriptTable readScriptTable(TTFDataStream data,
 long offset)
                                            throws IOException

Throws:

IOException

readLangSysTable

GlyphSubstitutionTable.LangSysTable readLangSysTable(TTFDataStream data,
 long offset)
                                              throws IOException

Throws:

IOException

readFeatureList

GlyphSubstitutionTable.FeatureRecord[] readFeatureList(TTFDataStream data,
 long offset)
                                                throws IOException

Throws:

IOException

readFeatureTable

GlyphSubstitutionTable.FeatureTable readFeatureTable(TTFDataStream data,
 long offset)
                                              throws IOException

Throws:

IOException

readLookupList

GlyphSubstitutionTable.LookupTable[] readLookupList(TTFDataStream data,
 long offset)
                                             throws IOException

Throws:

IOException

readLookupTable

GlyphSubstitutionTable.LookupTable readLookupTable(TTFDataStream data,
 long offset)
                                            throws IOException

Throws:

IOException

readLookupSubTable

GlyphSubstitutionTable.LookupSubTable readLookupSubTable(TTFDataStream data,
 long offset)
                                                  throws IOException

Throws:

IOException

readCoverageTable

GlyphSubstitutionTable.CoverageTable readCoverageTable(TTFDataStream data,
 long offset)
                                                throws IOException

Throws:

IOException

selectScriptTag

private String selectScriptTag(String[] tags)

Choose from one of the supplied OpenType script tags, depending on what the font supports and potentially on context.

Parameters:

tags -

Returns:

The best OpenType script tag

getLangSysTables

private Collection<GlyphSubstitutionTable.LangSysTable> getLangSysTables(String scriptTag)

getFeatureRecords

private List<GlyphSubstitutionTable.FeatureRecord> getFeatureRecords(Collection<GlyphSubstitutionTable.LangSysTable> langSysTables,
 List<String> enabledFeatures)

Get a list of FeatureRecords from a collection of LangSysTables. Optionally filter the returned features by supplying a list of allowed feature tags in enabledFeatures. Note that features listed as required (LangSysTable#requiredFeatureIndex) will be included even if not explicitly enabled.

Parameters:

langSysTables - The LangSysTables indicating FeatureRecords to search for

enabledFeatures - An optional list of feature tags (null to allow all)

Returns:

The indicated FeatureRecords

containsFeature

private boolean containsFeature(List<GlyphSubstitutionTable.FeatureRecord> featureRecords,
 String featureTag)

removeFeature

private void removeFeature(List<GlyphSubstitutionTable.FeatureRecord> featureRecords,
 String featureTag)

applyFeature

private int applyFeature(GlyphSubstitutionTable.FeatureRecord featureRecord,
 int gid)

doLookup

private int doLookup(GlyphSubstitutionTable.LookupTable lookupTable,
 int gid)

getSubstitution

public int getSubstitution(int gid,
 String[] scriptTags,
 List<String> enabledFeatures)

Apply glyph substitutions to the supplied gid. The applicable substitutions are determined by the scriptTags which indicate the language of the gid, and by the list of enabledFeatures. To ensure that a single gid isn't mapped to multiple substitutions, subsequent invocations with the same gid will return the same result as the first, regardless of script or enabled features.

Parameters:

gid - GID

scriptTags - Script tags applicable to the gid (see OpenTypeScript)

enabledFeatures - list of features to apply

getUnsubstitution

public int getUnsubstitution(int sgid)

For a substitute-gid (obtained from getSubstitution(int, String[], List)), retrieve the original gid. Only gids previously substituted by this instance can be un-substituted. If you are trying to unsubstitute before you substitute, something is wrong.

Parameters:

sgid - Substitute GID

readRangeRecord

GlyphSubstitutionTable.RangeRecord readRangeRecord(TTFDataStream data)
                                            throws IOException

Throws:

IOException