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.

Author:

Aaron Madlon-Kay

Field Summary

Fields

Modifier and Type	Field	Description
static final String	TAG

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

initialized

Method Summary

Modifier and Type	Method	Description
GsubData	getGsubData()	Returns a GsubData instance containing all scripts of the table.
GsubData	getGsubData(String scriptTag)	Builds a new GsubData instance for given script tag.
int	getSubstitution(int gid, String[] scriptTags, List<String> enabledFeatures)	Apply glyph substitutions to the supplied gid.
Set<String>	getSupportedScriptTags()
int	getUnsubstitution(int sgid)	For a substitute-gid (obtained from getSubstitution(int, String[], List)), retrieve the original gid.

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

getCheckSum, getInitialized, getLength, getOffset, getTag

Methods inherited from class java.lang.Object

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

Field Details

TAG

public static final String TAG

See Also:

• Constant Field Values

Method Details

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

Returns:

the id of the glyph substitution

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

Returns:

the original gid of a substitute-gid

getGsubData

public GsubData getGsubData()

Returns a GsubData instance containing all scripts of the table.

Returns:

the GsubData instance representing the table

getGsubData

public GsubData getGsubData(String scriptTag)

Builds a new GsubData instance for given script tag. In contrast to neighbour getGsubData() method, this one does not try to find the first supported language and load GSUB data for it. Instead, it fetches the data for the given scriptTag (if it's supported by the font) leaving the language unspecified. It means that even after successful reading of GSUB data, the actual glyph substitution may not work if there is no corresponding GsubWorker implementation for it. Note: This method performs searching on every invocation (no results are cached)

Parameters:

scriptTag - a script tag for which the data is needed

Returns:

GSUB data for the given script or null if no such script in the font

getSupportedScriptTags

public Set<String> getSupportedScriptTags()

Returns:

a read-only view of the script tags for which this GSUB table has records