/*
LinebreakableChain.java
*
* Copyright (c) 2000-2001, Ted Nelson and Tuomas Lukka
*
* This file is part of Gzz.
*
* Gzz is free software; you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* Gzz is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
* Public License for more details.
*
* You should have received a copy of the GNU Lesser General
* Public License along with Gzz; if not, write to the Free
* Software Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*
*
*/
/*
* Written by Tuomas Lukka
*/
package org.nongnu.libvob.linebreaking;
import org.nongnu.libvob.*;
import java.util.*;
/** Default impl of HChain
.
*/
public class LinebreakableChain implements HChain {
String rcsid = "$Id: LinebreakableChain.java,v 1.1 2003/03/16 15:55:04 benja Exp $";
public static final int GLUE_LENGTH = 0;
public static final int GLUE_STRETCH = 1;
public static final int GLUE_SHRINK = 2;
public static final int BREAKS = 3;
protected static final int PROPERTIES = 4;
int nboxes;
protected HBox[] boxes;
public LinebreakableChain() {
allocCopy(20);
}
/** For each Vob in boxes, three values:
* natural, plus, minus.
* This is glue that comes before the
* vob.
* XXX Should glues also be virtual and have scale?
* fonts scale non-uniformly, so should glue?
*/
protected float[] glues;
public void addBox(HBox box) {
ensureBoxes(nboxes+1, false);
int ind = nboxes++;
boxes[ind] = box;
if(ind > 0)
box.setPrev(boxes[ind-1]);
}
public void addGlue(float len, float str, float shr) {
glues[nboxes*PROPERTIES + GLUE_LENGTH] += len;
glues[nboxes*PROPERTIES + GLUE_STRETCH] += str;
glues[nboxes*PROPERTIES + GLUE_SHRINK] += shr;
}
public void addBreak() {
glues[nboxes*PROPERTIES + BREAKS]++;
}
public int length() {
return nboxes;
}
public HBox getBox(int n) {
return boxes[n];
}
public float getGlue(int n, int property) {
if(property < 0 || property > 2)
throw new IllegalArgumentException("illegal property: "+property);
return glues[(n * PROPERTIES) + property];
}
public int getBreaks(int n) {
return (int)glues[(n * PROPERTIES) + BREAKS];
}
/** Expand the arrays to contain space for n
boxes.
* This is called by ensureBoxes
when there is not enough
* space in the arrays. It simply creates new, larger arrays and
* copies the values from the old arrays into the new ones.
*/
void allocCopy(int n) {
HBox[] nboxes = new HBox[n];
float[] nglues = new float[PROPERTIES*(n+1)];
if(boxes != null) {
System.arraycopy(boxes, 0, nboxes, 0, boxes.length);
System.arraycopy(glues, 0, nglues, 0, glues.length);
}
boxes = nboxes;
glues = nglues;
}
/** Ensure that at least n
boxes fit into the arrays.
* Checks whether n
is larger than the number of boxes
* that currently fit into the arrays, and if so, calls
* allocCopy
to increase the arrays' size.
* @param accurate If the arrays don't suffice, whether to create
* arrays exactly of size n
. Setting this
* to true is only reasonable if it is expected that no
* more than n
boxes will be added to
* this chain.
*/
void ensureBoxes(int n, boolean accurate) {
if(boxes == null) allocCopy(accurate ? n : n > 50 ? n : 50);
if(boxes.length < n) {
int def = 2 * boxes.length;
allocCopy(accurate ? n : n > def ? n : def);
}
}
public float getAscent(int start, int end, float scale) {
float h = 0;
for(int i=start; i h) h = curh;
}
return h;
}
public float getDescent(int start, int end, float scale) {
float d = 0;
for(int i=start; i d) d = curd;
}
return d;
}
public float getHeight(int start, int end, float scale) {
return getAscent(start, end, scale) + getDescent(start, end, scale);
}
/** A style of glue.
* Constructed from a text style, a glue style represents the kind of
* glue that matches the text style (so that a space glue is as wide
* as a space of that text style, etc.). When glue needs to be added
* to the chain, call GlueStyle.addSpace
,
* GlueStyle.addCommaSpace
, or
* GlueStyle.addSentenceSpace
. (All three do the same
* thing currently, but subclasses can override the behavior.)
*/
static public class GlueStyle {
public GlueStyle(TextStyle st) {
spc_g = (int)st.getWidth(" ", 1);
spc_p = spc_g / 2;
spc_m = spc_g / 2;
if(spc_p == 0) spc_p = 1;
}
int spc_g, spc_p, spc_m;
public void addSpace(LinebreakableChain ch) {
ch.addGlue(spc_g, spc_p, spc_m);
}
public void addCommaSpace(LinebreakableChain ch) {
ch.addGlue(spc_g, spc_p, spc_m);
}
public void addSentenceSpace(LinebreakableChain ch) {
ch.addGlue(spc_g, spc_p, spc_m);
}
}
}