org.apache.fop.complexscripts.fonts.GlyphSubstitutionSubtable Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* $Id$ */
package org.apache.fop.complexscripts.fonts;
import org.apache.fop.complexscripts.util.GlyphSequence;
import org.apache.fop.complexscripts.util.ScriptContextTester;
// CSOFF: LineLengthCheck
/**
* The GlyphSubstitutionSubtable implements an abstract base of a glyph substitution subtable,
* providing a default implementation of the GlyphSubstitution interface.
*
* This work was originally authored by Glenn Adams ([email protected]).
*/
public abstract class GlyphSubstitutionSubtable extends GlyphSubtable implements GlyphSubstitution {
private static final GlyphSubstitutionState STATE = new GlyphSubstitutionState();
/**
* Instantiate a GlyphSubstitutionSubtable.
* @param id subtable identifier
* @param sequence subtable sequence
* @param flags subtable flags
* @param format subtable format
* @param coverage subtable coverage table
*/
protected GlyphSubstitutionSubtable(String id, int sequence, int flags, int format, GlyphCoverageTable coverage) {
super(id, sequence, flags, format, coverage);
}
/** {@inheritDoc} */
public int getTableType() {
return GlyphTable.GLYPH_TABLE_TYPE_SUBSTITUTION;
}
/** {@inheritDoc} */
public String getTypeName() {
return GlyphSubstitutionTable.getLookupTypeName(getType());
}
/** {@inheritDoc} */
public boolean isCompatible(GlyphSubtable subtable) {
return subtable instanceof GlyphSubstitutionSubtable;
}
/** {@inheritDoc} */
public boolean usesReverseScan() {
return false;
}
/** {@inheritDoc} */
public boolean substitute(GlyphSubstitutionState ss) {
return false;
}
/**
* Apply substitutions 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 (copy input glyph 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 apply default action for all remaining
* glyphs in input sequence.
* @param ss substitution state
* @param sta array of subtables to apply
* @param sequenceIndex if non negative, then apply subtables only at specified sequence index
* @return output glyph sequence
*/
public static final GlyphSequence substitute(GlyphSubstitutionState ss, GlyphSubstitutionSubtable[] sta, int sequenceIndex) {
int sequenceStart = ss.getPosition();
boolean appliedOneShot = false;
while (ss.hasNext()) {
boolean applied = false;
if (!appliedOneShot && ss.maybeApplicable()) {
for (int i = 0, n = sta.length; !applied && (i < n); i++) {
if (sequenceIndex < 0) {
applied = ss.apply(sta [ i ]);
} else if (ss.getPosition() == (sequenceStart + sequenceIndex)) {
applied = ss.apply(sta [ i ]);
if (applied) {
appliedOneShot = true;
}
}
}
}
if (!applied || !ss.didConsume()) {
ss.applyDefault();
}
ss.next();
}
return ss.getOutput();
}
/**
* Apply substitutions.
* @param gs input glyph sequence
* @param script tag
* @param language tag
* @param feature tag
* @param sta subtable array
* @param sct script context tester
* @return output glyph sequence
*/
public static final GlyphSequence substitute(GlyphSequence gs, String script, String language, String feature, GlyphSubstitutionSubtable[] sta, ScriptContextTester sct) {
synchronized (STATE) {
return substitute(STATE.reset(gs, script, language, feature, sct), sta, -1);
}
}
}