Package org.apache.fop.complexscripts.scripts

Class ScriptProcessor

java.lang.Object
org.apache.fop.complexscripts.scripts.ScriptProcessor
Direct Known Subclasses:
DefaultScriptProcessor
public abstract class ScriptProcessor extends Object

Abstract script processor base class for which an implementation of the substitution and positioning methods must be supplied.

This work was originally authored by Glenn Adams (gadams@apache.org).

  • Constructor Details

    • ScriptProcessor

      protected ScriptProcessor(String script)
      Instantiate a script processor.
      Parameters:
      script - a script identifier

  • Method Details

    • getScript

      public final String getScript()
      Returns:
      script identifier

    • getSubstitutionFeatures

      public abstract String[] getSubstitutionFeatures()
      Obtain script specific required substitution features.
      Returns:
      array of suppported substitution features or null

    • getOptionalSubstitutionFeatures

      public String[] getOptionalSubstitutionFeatures()
      Obtain script specific optional substitution features.
      Returns:
      array of suppported substitution features or null

    • getSubstitutionContextTester

      public abstract ScriptContextTester getSubstitutionContextTester()
      Obtain script specific substitution context tester.
      Returns:
      substitution context tester or null

    • substitute

      public final GlyphSequence substitute(GlyphSubstitutionTable gsub, GlyphSequence gs, String script, String language, Map<GlyphTable.LookupSpec,List<GlyphTable.LookupTable>> lookups)
      Perform substitution processing using a specific set of lookup tables.
      Parameters:
      gsub - the glyph substitution table that applies
      gs - an input glyph sequence
      script - a script identifier
      language - a language identifier
      lookups - a mapping from lookup specifications to glyph subtables to use for substitution processing
      Returns:
      the substituted (output) glyph sequence

    • substitute

      public GlyphSequence substitute(GlyphSequence gs, String script, String language, GlyphTable.UseSpec[] usa, ScriptContextTester sct)
      Perform substitution processing using a specific set of ordered glyph table use specifications.
      Parameters:
      gs - an input glyph sequence
      script - a script identifier
      language - a language identifier
      usa - an ordered array of glyph table use specs
      sct - a script specific context tester (or null)
      Returns:
      the substituted (output) glyph sequence

    • reorderCombiningMarks

      public GlyphSequence reorderCombiningMarks(GlyphDefinitionTable gdef, GlyphSequence gs, int[] unscaledWidths, int[][] gpa, String script, String language)
      Reorder combining marks in glyph sequence so that they precede (within the sequence) the base character to which they are applied. N.B. In the case of RTL segments, marks are not reordered by this, method since when the segment is reversed by BIDI processing, marks are automatically reordered to precede their base glyph.
      Parameters:
      gdef - the glyph definition table that applies
      gs - an input glyph sequence
      unscaledWidths - associated unscaled advance widths (also reordered)
      gpa - associated glyph position adjustments (also reordered)
      script - a script identifier
      language - a language identifier
      Returns:
      the reordered (output) glyph sequence

    • getPositioningFeatures

      public abstract String[] getPositioningFeatures()
      Obtain script specific required positioning features.
      Returns:
      array of suppported positioning features or null

    • getOptionalPositioningFeatures

      public String[] getOptionalPositioningFeatures()
      Obtain script specific optional positioning features.
      Returns:
      array of suppported positioning features or null

    • getPositioningContextTester

      public abstract ScriptContextTester getPositioningContextTester()
      Obtain script specific positioning context tester.
      Returns:
      positioning context tester or null

    • position

      public final boolean position(GlyphPositioningTable gpos, GlyphSequence gs, String script, String language, int fontSize, Map<GlyphTable.LookupSpec,List<GlyphTable.LookupTable>> lookups, int[] widths, int[][] adjustments)
      Perform positioning processing using a specific set of lookup tables.
      Parameters:
      gpos - the glyph positioning table that applies
      gs - an input glyph sequence
      script - a script identifier
      language - a language identifier
      fontSize - size in device units
      lookups - a mapping from lookup specifications to glyph subtables to use for positioning processing
      widths - array of default advancements for each glyph
      adjustments - accumulated adjustments array (sequence) of 4-tuples of placement [PX,PY] and advance [AX,AY] adjustments, in that order, with one 4-tuple for each element of glyph sequence
      Returns:
      true if some adjustment is not zero; otherwise, false

    • position

      public boolean position(GlyphSequence gs, String script, String language, int fontSize, GlyphTable.UseSpec[] usa, int[] widths, int[][] adjustments, ScriptContextTester sct)
      Perform positioning processing using a specific set of ordered glyph table use specifications.
      Parameters:
      gs - an input glyph sequence
      script - a script identifier
      language - a language identifier
      fontSize - size in device units
      usa - an ordered array of glyph table use specs
      widths - array of default advancements for each glyph in font
      adjustments - accumulated adjustments array (sequence) of 4-tuples of placement [PX,PY] and advance [AX,AY] adjustments, in that order, with one 4-tuple for each element of glyph sequence
      sct - a script specific context tester (or null)
      Returns:
      true if some adjustment is not zero; otherwise, false

    • assembleLookups

      public final GlyphTable.UseSpec[] assembleLookups(GlyphTable table, String[] features, Map<GlyphTable.LookupSpec,List<GlyphTable.LookupTable>> lookups)
      Assemble ordered array of lookup table use specifications according to the specified features and candidate lookups, where the order of the array is in accordance to the order of the applicable lookup list.
      Parameters:
      table - the governing glyph table
      features - array of feature identifiers to apply
      lookups - a mapping from lookup specifications to lists of look tables from which to select lookup tables according to the specified features
      Returns:
      ordered array of assembled lookup table use specifications

    • getInstance

      public static ScriptProcessor getInstance(String script, Map<String,ScriptProcessor> processors)
      Obtain script processor instance associated with specified script.
      Parameters:
      script - a script identifier
      Returns:
      a script processor instance or null if none found

    • preProcess

      public CharSequence preProcess(CharSequence charSequence, MultiByteFont font, List associations)