Class ScriptProcessor

  • Direct Known Subclasses:
    DefaultScriptProcessor

    public abstract class ScriptProcessor
    extends java.lang.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 Detail

      • ScriptProcessor

        protected ScriptProcessor​(java.lang.String script)
        Instantiate a script processor.
        Parameters:
        script - a script identifier
    • Method Detail

      • getScript

        public final java.lang.String getScript()
        Returns:
        script identifier
      • getSubstitutionFeatures

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

        public java.lang.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,
                                              java.lang.String script,
                                              java.lang.String language,
                                              java.util.Map<GlyphTable.LookupSpec,​java.util.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,
                                        java.lang.String script,
                                        java.lang.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,
                                                   java.lang.String script,
                                                   java.lang.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 java.lang.String[] getPositioningFeatures()
        Obtain script specific required positioning features.
        Returns:
        array of suppported positioning features or null
      • getOptionalPositioningFeatures

        public java.lang.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,
                                      java.lang.String script,
                                      java.lang.String language,
                                      int fontSize,
                                      java.util.Map<GlyphTable.LookupSpec,​java.util.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,
                                java.lang.String script,
                                java.lang.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,
                                                          java.lang.String[] features,
                                                          java.util.Map<GlyphTable.LookupSpec,​java.util.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​(java.lang.String script,
                                                  java.util.Map<java.lang.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
      • createProcessor

        private static ScriptProcessor createProcessor​(java.lang.String script)
      • preProcess

        public java.lang.CharSequence preProcess​(java.lang.CharSequence charSequence,
                                                 MultiByteFont font,
                                                 java.util.List associations)