001: /*
002: * Licensed to the Apache Software Foundation (ASF) under one or more
003: * contributor license agreements. See the NOTICE file distributed with
004: * this work for additional information regarding copyright ownership.
005: * The ASF licenses this file to You under the Apache License, Version 2.0
006: * (the "License"); you may not use this file except in compliance with
007: * the License. You may obtain a copy of the License at
008: *
009: * http://www.apache.org/licenses/LICENSE-2.0
010: *
011: * Unless required by applicable law or agreed to in writing, software
012: * distributed under the License is distributed on an "AS IS" BASIS,
013: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014: * See the License for the specific language governing permissions and
015: * limitations under the License.
016: */
017:
018: /* $Id: KnuthGlue.java 426576 2006-07-28 15:44:37Z jeremias $ */
019:
020: package org.apache.fop.layoutmgr;
021:
022: /**
023: * An instance of this class represents a piece of content with adjustable
024: * width: for example a space between words of justified text.
025: *
026: * A KnuthGlue is a feasible breaking point only if it immediately follows
027: * a KnuthBox.
028: *
029: * The represented piece of content is suppressed if either the KnuthGlue
030: * is a chosen breaking point or there isn't any KnuthBox between the
031: * previous breaking point and the KnuthGlue itself.
032: *
033: * So, an unsuppressible piece of content with adjustable width, for example
034: * a leader or a word with adjustable letter space, cannot be represented
035: * by a single KnuthGlue; it can be represented using the sequence:
036: * KnuthBox(width = 0)
037: * KnuthPenalty(width = 0, penalty = infinity)
038: * KnuthGlue(...)
039: * KnuthBox(width = 0)
040: * where the infinity penalty avoids choosing the KnuthGlue as a breaking point
041: * and the 0-width KnuthBoxes prevent suppression.
042: *
043: * Besides the inherited methods and attributes, this class has two attributes
044: * used to store the stretchability (difference between max and opt width) and
045: * the shrinkability (difference between opt and min width), and the methods
046: * to get these values.
047: */
048: public class KnuthGlue extends KnuthElement {
049:
050: private int stretchability;
051: private int shrinkability;
052: private int adjustmentClass = -1;
053:
054: /**
055: * Create a new KnuthGlue.
056: *
057: * @param w the width of this glue
058: * @param y the stretchability of this glue
059: * @param z the shrinkability of this glue
060: * @param pos the Position stored in this glue
061: * @param bAux is this glue auxiliary?
062: */
063: public KnuthGlue(int w, int y, int z, Position pos, boolean bAux) {
064: super (w, pos, bAux);
065: stretchability = y;
066: shrinkability = z;
067: }
068:
069: public KnuthGlue(int w, int y, int z, int iAdjClass, Position pos,
070: boolean bAux) {
071: super (w, pos, bAux);
072: stretchability = y;
073: shrinkability = z;
074: adjustmentClass = iAdjClass;
075: }
076:
077: /** @see org.apache.fop.layoutmgr.KnuthElement#isGlue() */
078: public boolean isGlue() {
079: return true;
080: }
081:
082: /** @return the stretchability of this glue. */
083: public int getY() {
084: return stretchability;
085: }
086:
087: /** @return the shrinkability of this glue. */
088: public int getZ() {
089: return shrinkability;
090: }
091:
092: /** @return the adjustment class (or role) of this glue. */
093: public int getAdjustmentClass() {
094: return adjustmentClass;
095: }
096:
097: /** @see java.lang.Object#toString() */
098: public String toString() {
099: StringBuffer sb = new StringBuffer(64);
100: if (isAuxiliary()) {
101: sb.append("aux. ");
102: }
103: sb.append("glue");
104: sb.append(" w=").append(getW());
105: sb.append(" stretch=").append(getY());
106: sb.append(" shrink=").append(getZ());
107: if (getAdjustmentClass() >= 0) {
108: sb.append(" adj-class=").append(getAdjustmentClass());
109: }
110: return sb.toString();
111: }
112:
113: }
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