org.apache.fop.complexscripts.fonts

Class GlyphPositioningSubtable

java.lang.Object

org.apache.fop.complexscripts.fonts.GlyphSubtable

org.apache.fop.complexscripts.fonts.GlyphPositioningSubtable

All Implemented Interfaces:

Comparable, GlyphPositioning

public abstract class GlyphPositioningSubtable
extends GlyphSubtable
implements GlyphPositioning

The GlyphPositioningSubtable implements an abstract base of a glyph subtable, providing a default implementation of the GlyphPositioning interface.

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

Field Summary

Fields inherited from class org.apache.fop.complexscripts.fonts.GlyphSubtable

LF_IGNORE_BASE, LF_IGNORE_LIGATURE, LF_IGNORE_MARK, LF_INTERNAL_USE_REVERSE_SCAN, LF_MARK_ATTACHMENT_TYPE, LF_RESERVED, LF_RIGHT_TO_LEFT, LF_USE_MARK_FILTERING_SET

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	GlyphPositioningSubtable(String id, int sequence, int flags, int format, GlyphCoverageTable coverage) Instantiate a GlyphPositioningSubtable.

Method Summary

Methods

Modifier and Type	Method and Description
int	getTableType()
String	getTypeName()
boolean	isCompatible(GlyphSubtable subtable) Determine if a glyph subtable is compatible with this glyph subtable.
boolean	position(GlyphPositioningState ps) Perform glyph positioning at the current index, mutating the positioning state object as required.
static boolean	position(GlyphPositioningState ps, GlyphPositioningSubtable[] sta, int sequenceIndex) Apply positioning using specified state and subtable array.
static boolean	position(GlyphSequence gs, String script, String language, String feature, int fontSize, GlyphPositioningSubtable[] sta, int[] widths, int[][] adjustments, ScriptContextTester sct) Apply positioning.
boolean	usesReverseScan()

Methods inherited from class org.apache.fop.complexscripts.fonts.GlyphSubtable

compareTo, equals, getClasses, getCoverage, getCoverageIndex, getCoverageSize, getEntries, getFlags, getFlags, getFormat, getGDEF, getLookupId, getSequence, getTable, getType, hashCode, resolveLookupReferences, setTable, usesReverseScan

Methods inherited from class java.lang.Object

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

Constructor Detail

GlyphPositioningSubtable

protected GlyphPositioningSubtable(String id,
                        int sequence,
                        int flags,
                        int format,
                        GlyphCoverageTable coverage)

Instantiate a GlyphPositioningSubtable.

Parameters:

id - subtable identifier

sequence - subtable sequence

flags - subtable flags

format - subtable format

coverage - subtable coverage table

Method Detail

getTableType

public int getTableType()

Specified by:

getTableType in class GlyphSubtable

Returns:

this subtable's table type

getTypeName

public String getTypeName()

Specified by:

getTypeName in class GlyphSubtable

Returns:

this subtable's type name

isCompatible

public boolean isCompatible(GlyphSubtable subtable)

Determine if a glyph subtable is compatible with this glyph subtable. Two glyph subtables are compatible if the both may appear in a single lookup table.

Specified by:

isCompatible in class GlyphSubtable

Parameters:

subtable - a glyph subtable to determine compatibility

Returns:

true if specified subtable is compatible with this glyph subtable, where by compatible is meant that they share the same lookup type

usesReverseScan

public boolean usesReverseScan()

Specified by:

usesReverseScan in class GlyphSubtable

Returns:

true if subtable uses reverse scanning of glyph sequence, meaning from the last glyph in a glyph sequence to the first glyph

position

public boolean position(GlyphPositioningState ps)

Perform glyph positioning at the current index, mutating the positioning state object as required. Only the context associated with the current index is processed.

Specified by:

position in interface GlyphPositioning

Parameters:

ps - glyph positioning state object

Returns:

true if the glyph subtable applies, meaning that the current context matches the associated input context glyph coverage table; note that returning true does not mean any position adjustment occurred; it only means that no further glyph subtables for the current lookup table should be applied.

position

public static final boolean position(GlyphPositioningState ps,
               GlyphPositioningSubtable[] sta,
               int sequenceIndex)

Apply positioning using specified state and subtable array. For each position in input sequence, apply subtables in order until some subtable applies or none remain. If no subtable applied or no input was consumed for a given position, then apply default action (no adjustments and advance). If sequenceIndex is non-negative, then apply subtables only when current position matches sequenceIndex in relation to the starting position. Furthermore, upon successful application at sequenceIndex, then discontinue processing the remaining

Parameters:

ps - positioning state

sta - array of subtables to apply

sequenceIndex - if non negative, then apply subtables only at specified sequence index

Returns:

true if a non-zero adjustment occurred

position

public static final boolean position(GlyphSequence gs,
               String script,
               String language,
               String feature,
               int fontSize,
               GlyphPositioningSubtable[] sta,
               int[] widths,
               int[][] adjustments,
               ScriptContextTester sct)

Apply positioning.

Parameters:

gs - input glyph sequence

script - tag

language - tag

feature - tag

fontSize - the font size

sta - subtable array

widths - array

adjustments - array (receives output adjustments)

sct - script context tester

Returns:

true if a non-zero adjustment occurred