1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
|
/*
* 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.layoutmgr;
import java.util.LinkedList;
import java.util.List;
import java.util.ListIterator;
import java.util.Stack;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.fop.area.Area;
import org.apache.fop.area.BlockParent;
import org.apache.fop.fo.pagination.Flow;
/**
* LayoutManager for an fo:flow object.
* Its parent LM is the PageSequenceLayoutManager.
* This LM is responsible for getting columns of the appropriate size
* and filling them with block-level areas generated by its children.
* @todo Reintroduce emergency counter (generate error to avoid endless loop)
*/
public class FlowLayoutManager extends BlockStackingLayoutManager
implements BlockLevelLayoutManager {
/**
* logging instance
*/
private static Log log = LogFactory.getLog(FlowLayoutManager.class);
/** Array of areas currently being filled stored by area class */
private BlockParent[] currentAreas = new BlockParent[Area.CLASS_MAX];
/**
* This is the top level layout manager.
* It is created by the PageSequence FO.
* @param pslm parent PageSequenceLayoutManager object
* @param node Flow object
*/
public FlowLayoutManager(PageSequenceLayoutManager pslm, Flow node) {
super(node);
setParent(pslm);
}
/** {@inheritDoc} */
public List getNextKnuthElements(LayoutContext context, int alignment) {
List elements = new LinkedList();
LayoutManager currentChildLM;
while ((currentChildLM = getChildLM()) != null) {
if (addChildElements(elements, currentChildLM, context, alignment) != null) {
return elements;
}
}
SpaceResolver.resolveElementList(elements);
setFinished(true);
assert !elements.isEmpty();
return elements;
}
/** {@inheritDoc} */
public List getNextKnuthElements(LayoutContext context, int alignment,
Position positionAtIPDChange, LayoutManager restartAtLM) {
List elements = new LinkedList();
LayoutManager currentChildLM = positionAtIPDChange.getLM();
if (currentChildLM == null) {
throw new IllegalStateException(
"Cannot find layout manager from where to re-start layout after IPD change");
}
if (restartAtLM != null && restartAtLM.getParent() == this) {
currentChildLM = restartAtLM;
setCurrentChildLM(currentChildLM);
currentChildLM.reset();
if (addChildElements(elements, currentChildLM, context, alignment) != null) {
return elements;
}
} else {
Stack lmStack = new Stack();
while (currentChildLM.getParent() != this) {
lmStack.push(currentChildLM);
currentChildLM = currentChildLM.getParent();
}
setCurrentChildLM(currentChildLM);
if (addChildElements(elements, currentChildLM, context, alignment, lmStack,
positionAtIPDChange, restartAtLM) != null) {
return elements;
}
}
while ((currentChildLM = getChildLM()) != null) {
currentChildLM.reset(); // TODO won't work with forced breaks
if (addChildElements(elements, currentChildLM, context, alignment) != null) {
return elements;
}
}
SpaceResolver.resolveElementList(elements);
setFinished(true);
assert !elements.isEmpty();
return elements;
}
private List addChildElements(List elements, LayoutManager childLM, LayoutContext context,
int alignment) {
return addChildElements(elements, childLM, context, alignment, null, null, null);
}
private List addChildElements(List elements, LayoutManager childLM, LayoutContext context,
int alignment, Stack lmStack, Position position, LayoutManager restartAtLM) {
if (handleSpanChange(childLM, elements, context)) {
SpaceResolver.resolveElementList(elements);
return elements;
}
LayoutContext childLC = new LayoutContext(0);
List childrenElements = getNextChildElements(childLM, context, childLC, alignment, lmStack,
position, restartAtLM);
if (elements.isEmpty()) {
context.updateKeepWithPreviousPending(childLC.getKeepWithPreviousPending());
}
if (!elements.isEmpty()
&& !ElementListUtils.startsWithForcedBreak(childrenElements)) {
addInBetweenBreak(elements, context, childLC);
}
context.updateKeepWithNextPending(childLC.getKeepWithNextPending());
elements.addAll(childrenElements);
if (ElementListUtils.endsWithForcedBreak(elements)) {
// a descendant of this flow has break-before or break-after
if (childLM.isFinished() && !hasNextChildLM()) {
setFinished(true);
}
SpaceResolver.resolveElementList(elements);
return elements;
}
return null;
}
private boolean handleSpanChange(LayoutManager childLM, List elements, LayoutContext context) {
int span = EN_NONE;
int disableColumnBalancing = EN_FALSE;
if (childLM instanceof BlockLayoutManager) {
span = ((BlockLayoutManager)childLM).getBlockFO().getSpan();
disableColumnBalancing = ((BlockLayoutManager) childLM).getBlockFO()
.getDisableColumnBalancing();
} else if (childLM instanceof BlockContainerLayoutManager) {
span = ((BlockContainerLayoutManager)childLM).getBlockContainerFO().getSpan();
disableColumnBalancing = ((BlockContainerLayoutManager) childLM).getBlockContainerFO()
.getDisableColumnBalancing();
}
int currentSpan = context.getCurrentSpan();
if (currentSpan != span) {
if (span == EN_ALL) {
context.setDisableColumnBalancing(disableColumnBalancing);
}
log.debug("span change from " + currentSpan + " to " + span);
context.signalSpanChange(span);
return true;
} else {
return false;
}
}
private List getNextChildElements(LayoutManager childLM, LayoutContext context,
LayoutContext childLC, int alignment, Stack lmStack, Position restartPosition,
LayoutManager restartLM) {
childLC.setStackLimitBP(context.getStackLimitBP());
childLC.setRefIPD(context.getRefIPD());
childLC.setWritingMode(getCurrentPage().getSimplePageMaster().getWritingMode());
List childrenElements;
if (lmStack == null) {
childrenElements = childLM.getNextKnuthElements(childLC, alignment);
} else {
childrenElements = childLM.getNextKnuthElements(childLC,
alignment, lmStack, restartPosition, restartLM);
}
assert !childrenElements.isEmpty();
// "wrap" the Position inside each element
List tempList = childrenElements;
childrenElements = new LinkedList();
wrapPositionElements(tempList, childrenElements);
return childrenElements;
}
/**
* {@inheritDoc}
*/
public int negotiateBPDAdjustment(int adj, KnuthElement lastElement) {
log.debug(" FLM.negotiateBPDAdjustment> " + adj);
if (lastElement.getPosition() instanceof NonLeafPosition) {
// this element was not created by this FlowLM
NonLeafPosition savedPos = (NonLeafPosition)lastElement.getPosition();
lastElement.setPosition(savedPos.getPosition());
int returnValue = ((BlockLevelLayoutManager)lastElement.getLayoutManager())
.negotiateBPDAdjustment(adj, lastElement);
lastElement.setPosition(savedPos);
log.debug(" FLM.negotiateBPDAdjustment> result " + returnValue);
return returnValue;
} else {
return 0;
}
}
/**
* {@inheritDoc}
*/
public void discardSpace(KnuthGlue spaceGlue) {
log.debug(" FLM.discardSpace> ");
if (spaceGlue.getPosition() instanceof NonLeafPosition) {
// this element was not created by this FlowLM
NonLeafPosition savedPos = (NonLeafPosition)spaceGlue.getPosition();
spaceGlue.setPosition(savedPos.getPosition());
((BlockLevelLayoutManager) spaceGlue.getLayoutManager()).discardSpace(spaceGlue);
spaceGlue.setPosition(savedPos);
}
}
/** {@inheritDoc} */
public Keep getKeepTogether() {
return Keep.KEEP_AUTO;
}
/** {@inheritDoc} */
public Keep getKeepWithNext() {
return Keep.KEEP_AUTO;
}
/** {@inheritDoc} */
public Keep getKeepWithPrevious() {
return Keep.KEEP_AUTO;
}
/** {@inheritDoc} */
public List getChangedKnuthElements(List oldList, /*int flaggedPenalty,*/ int alignment) {
ListIterator oldListIterator = oldList.listIterator();
KnuthElement returnedElement;
List returnedList = new LinkedList();
List returnList = new LinkedList();
KnuthElement prevElement = null;
KnuthElement currElement = null;
int fromIndex = 0;
// "unwrap" the Positions stored in the elements
KnuthElement oldElement;
while (oldListIterator.hasNext()) {
oldElement = (KnuthElement)oldListIterator.next();
if (oldElement.getPosition() instanceof NonLeafPosition) {
// oldElement was created by a descendant of this FlowLM
oldElement.setPosition((oldElement.getPosition()).getPosition());
} else {
// thisElement was created by this FlowLM, remove it
oldListIterator.remove();
}
}
// reset the iterator
oldListIterator = oldList.listIterator();
while (oldListIterator.hasNext()) {
currElement = (KnuthElement) oldListIterator.next();
if (prevElement != null
&& prevElement.getLayoutManager() != currElement.getLayoutManager()) {
// prevElement is the last element generated by the same LM
BlockLevelLayoutManager prevLM = (BlockLevelLayoutManager)
prevElement.getLayoutManager();
BlockLevelLayoutManager currLM = (BlockLevelLayoutManager)
currElement.getLayoutManager();
returnedList.addAll(prevLM.getChangedKnuthElements(
oldList.subList(fromIndex, oldListIterator.previousIndex()), alignment));
fromIndex = oldListIterator.previousIndex();
// there is another block after this one
if (prevLM.mustKeepWithNext()
|| currLM.mustKeepWithPrevious()) {
// add an infinite penalty to forbid a break between blocks
returnedList.add(new KnuthPenalty(0, KnuthElement.INFINITE, false,
new Position(this), false));
} else if (!((KnuthElement) returnedList.get(returnedList
.size() - 1)).isGlue()) {
// add a null penalty to allow a break between blocks
returnedList.add(new KnuthPenalty(0, 0, false, new Position(this), false));
}
}
prevElement = currElement;
}
if (currElement != null) {
BlockLevelLayoutManager currLM = (BlockLevelLayoutManager)
currElement.getLayoutManager();
returnedList.addAll(currLM.getChangedKnuthElements(
oldList.subList(fromIndex, oldList.size()), alignment));
}
// "wrap" the Position stored in each element of returnedList
// and add elements to returnList
ListIterator listIter = returnedList.listIterator();
while (listIter.hasNext()) {
returnedElement = (KnuthElement)listIter.next();
if (returnedElement.getLayoutManager() != this) {
returnedElement.setPosition(
new NonLeafPosition(this, returnedElement.getPosition()));
}
returnList.add(returnedElement);
}
return returnList;
}
/**
* {@inheritDoc}
*/
public void addAreas(PositionIterator parentIter, LayoutContext layoutContext) {
AreaAdditionUtil.addAreas(this, parentIter, layoutContext);
flush();
}
/**
* Add child area to a the correct container, depending on its
* area class. A Flow can fill at most one area container of any class
* at any one time. The actual work is done by BlockStackingLM.
*
* @param childArea the area to add
*/
public void addChildArea(Area childArea) {
getParentArea(childArea);
addChildToArea(childArea,
this.currentAreas[childArea.getAreaClass()]);
}
/**
* {@inheritDoc}
*/
public Area getParentArea(Area childArea) {
BlockParent parentArea = null;
int aclass = childArea.getAreaClass();
if (aclass == Area.CLASS_NORMAL) {
parentArea = getCurrentPV().getCurrentFlow();
} else if (aclass == Area.CLASS_BEFORE_FLOAT) {
parentArea = getCurrentPV().getBodyRegion().getBeforeFloat();
} else if (aclass == Area.CLASS_FOOTNOTE) {
parentArea = getCurrentPV().getBodyRegion().getFootnote();
} else {
throw new IllegalStateException("(internal error) Invalid "
+ "area class (" + aclass + ") requested.");
}
this.currentAreas[aclass] = parentArea;
setCurrentArea(parentArea);
return parentArea;
}
/**
* Returns the IPD of the content area
* @return the IPD of the content area
*/
public int getContentAreaIPD() {
return getCurrentPV().getCurrentSpan().getColumnWidth();
}
/**
* Returns the BPD of the content area
* @return the BPD of the content area
*/
public int getContentAreaBPD() {
return getCurrentPV().getBodyRegion().getBPD();
}
/** {@inheritDoc} */
public boolean isRestartable() {
return true;
}
}
|