summaryrefslogtreecommitdiffstats
path: root/layout/doc/table_reflow_slides.html
blob: e76a10768e0c04d8cb1f3afd92d4eca03e25dca9 (plain)
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
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
<!-- This Source Code Form is subject to the terms of the Mozilla Public
   - License, v. 2.0. If a copy of the MPL was not distributed with this
   - file, You can obtain one at http://mozilla.org/MPL/2.0/. -->

<!-- vim:sw=2:et:ts=2:tw=72:
-->
<!DOCTYPE html public "-//W3C//DTD HTML 4.01 Transitional//EN"
  "http://www.w3.org/TR/html4/loose.dtd">
<html lang="en-US">
<head>
  <title>Table Reflow Tech Talk, 2002-08-05</title>
  <style type="text/css">

  html, body {
    height: 100%;
    overflow: visible;
  }

  body {
    font-size: 1.4em;
    font-family: Verdana, Arial, Helvetica, sans-serif;
    font-weight: bold;
    background: white;
    color: black;
  }

  h1, h2, p {
    margin: 0;
  }

  h1 {
    font: inherit;
    font-size: 1.5em;
    /* text-align: center; */
    margin-bottom: 0.8em;
    border-bottom: 0.1em solid #006;
	color: #006;
  }

  h2 {
    font: inherit;
    font-size: 1.2em;
    text-align: left;
    margin: 0.15em 0;
  }

  ul {
    padding: 0 0 0 1.4em;
    margin: 0;
  }

  li { margin: 0; 
       margin-top: 0.5em; 
	   padding: 0; 
	   font-size: 1.0em;}

  div.slide {
    position: relative;
    min-height: 100%;
  }

  div.nav {
    /*
    position: absolute;
    top: 4px;
    right: 4px;
    */
    float: right;
    margin: 4px;
  }

  div.nav :link, div.nav :visited, div.nav span {
    text-decoration: none;
    background: #006;
    color: white;
    padding: 0 0.4em 0.2em 0.4em;
    line-height: 1.4em;
  }

  div.nav :link:hover, div.nav :visited:hover {
    background: #00f;
  }

  table {
    margin: auto;
  }

  table.box {
    border-collapse: collapse;
	border: 2px solid black;
	box-sizing: border-box;
	width:98%;
	height:96%;
  }

  row {
    border: 2px solid black;
  }
  row.title {
    border: hidden;
  }

  table td {
    /*text-align: center;*/
    empty-cells: hide;
  }

  table td.box {
    height:100%;
	border: 2px solid black;
  }

  table td.title {
    border-top: hidden;
    border-right: hidden;
    border-left: hidden;
	font-size: .5em;
  }

  table td.title2 {
    border-bottom: hidden;
    border-right: hidden;
    border-left: hidden;
	font-size: .5em;
  }

  table.tree tr:not(.arrows) td {
    font-family: monospace;
    border: 0.1em solid;
	font-size: .7em;
	text-align:center;
  }

  table td.left-arrow {
    text-align: right;
  }

  table td.right-arrow {
    text-align: left;
  }

  table td.center-arrow {
    text-align: center;
  }

  span.html {
    color:purple;
  }

  table td.space {
    width: 5%;
  }

  table td.frame {
    width: 22%;
  }

  span.comment {
    color: red;
  }

  </style>
</head>
<body>

<div class="slide" id="s0">
  <div class="nav">
    <a href="#s28">&lt;</a>
    <a href="#s1">&gt;</a>
  </div>
  <table style="margin: auto"><tr><td>
  <center>
    <h1>Table Reflow Internals<br>Tech Talk</h1>
    <p>Aug 5, 2002</p>
    <p style="margin-top: 0.5em">Chris Karnaze</a></p>
  </center>
  </td></tr></table>

</div>

<div class="slide" id="s1">
  <div class="nav">
    <a href="#s0">&lt;</a>
    <a href="#s2">&gt;</a>
  </div>
  <h1>Overview</h1>
  <ul>
    <li>Review of reflow</li>
    <li>Table frames</li>
    <li>Table reflow</li> 
    <li>Intro to paginated reflow</li>
    <li>Table paginated reflow</li>
  </ul>
</div>

<div class="slide" id="s2">
  <div class="nav">
    <a href="#s1">&lt;</a>
    <a href="#s3">&gt;</a>
  </div>
  <h1>Review of Reflow</h1>
  <ul>
    <li>Reflow process starts when
      <ul>
        <li>An html document starts loading (the frame tree contains only viewport, scroll(s), canvas, html, body).</li>
        <li>The initial chunk of an xml doc is loaded.</li> 
        <li>The initial chunk of an html doc (or a subsequent chunk of an xml doc) is loaded. The container posts a 
        dirty reflow command with itself as the target. </li>
        <li>Content is inserted, appended, or deleted through the DOM. The container posts a dirty reflow command 
        with itself as the target.</li>
        <li>Style changes through the DOM - javascript, browser change font (CTRL+/-), a preference changes, etc.</li>
      </ul>
	</li>
  </ul>
</div>

<div class="slide" id="s3">
  <div class="nav">
    <a href="#s2">&lt;</a>
    <a href="#s4">&gt;</a>
  </div>
  <h1>Review of Reflow</h1>
  <ul>
    <li>Reflow starts with pres shell
      <ul>
        <li>Which reflows the reflow root (usually the view port frame),</li>
        <li>Which reflows it children, etc.</li>
      </ul>
    </li>
    <li>Ususally it starts when the pres shell processes its queue of reflow commands.</li>
    <li>The reflower
	 <ul>
         <li>Positions reflowee (if it can) before actually reflowing in case views are involved 
		 (e.g. absolutely positioned elements) </li>
         <li>Reflows reflowee and passes a reflow state (in) and a reflow metrics (in/out)</li> 
	 </ul>
    </li>
  </ul>
</div>

<div class="slide" id="s4">
  <div class="nav">
    <a href="#s3">&lt;</a>
    <a href="#s5">&gt;</a>
  </div>
  <h1>Review of Reflow</h1>
  <ul>
    <li>The reflow state:
	 <ul>
      <li>Is a node in a tree structurally equivalent to the frame tree of reflow participants</li>
      <li>contains:
        <ul> 
         <li>reflow type,</li>
         <li>avail size,</li> 
         <li>various computed values,</li>
         <li>resolved style structs</li>
         <li>possible request for preferred size and more.</li>
        </ul>
      </li> 
     </ul>
    </li>
   </ul>
</div>

<div class="slide" id="s5">
  <div class="nav">
    <a href="#s4">&lt;</a>
    <a href="#s6">&gt;</a>
  </div>
  <h1>Review of Reflow</h1>
  <ul>
    </li>
      <li>the reflow metrics contains:
    	 <ul class=nested>
      <li>max element size (if requested) - the minimum size it can be</li> 
      <li>preferred size (if requested) - the size it would like to be given no size constraints.</li> 
      <li>desired size - the size it would like to be given the avail size. This
	  is equivalent to preferred size if the avail size is not constrained.</li>
	 </ul>
	</li>
      </ul>
</div>

<div class="slide" id="s6">
  <div class="nav">
    <a href="#s5">&lt;</a>
    <a href="#s7">&gt;</a>
  </div>
  <h1>Review of Reflow</h1>
 <ul>
 <li>The reflowee sets various sizes in the reflow metrics after (possibly) reflowing some or all of its children 
    which reflows it children, etc.</li>
 <li>The reflowee returns a reflow status which indicates
	 <ul class=nested>
      <li>if it is complete, and thus not have to continue (split)</li>
      <li>breaking status (in the case of some inline frames)</li> 
      <li>if there is truncation (it can't fit in the space and can't split). This is just a convience mechanism.</li>
	 </ul>
	</li>

</div>

<div class="slide" id="s7">
  <div class="nav">
    <a href="#s6">&lt;</a>
    <a href="#s8">&gt;</a>
  </div>

  <h1>Kinds of reflows</h1>
  <ul>
    <li>Initial - reflowee's first reflow must be of this type (reflower's responsibility).</li> 
    <li>Resize - reflowee gets a change in available space only. Similar to initial, except it can reoccur.</li> 
    <li>Incremental - has a reflow path (tree) where each node has a command with a target frame, <br>reflow command types are:</li> 
   	 <ul class=nested>
      <li>dirty - something changed inside a target (e.g. it gains, loses children)</li>
      <li>style changed - a target changed stylisticly (recall, size is a style property)</li> 
      <li>content changed - a target's content changed (e.g. a text run)</li> 
      <li>user defined - currently only used for fixed positioned frames </li> 
	 </ul>
	</li>
  </ul>
</div>

<div class="slide" id="s8">
  <div class="nav">
    <a href="#s7">&lt;</a>
    <a href="#s9">&gt;</a>
  </div>
  <h1>Kinds of reflows</h1>
  <ul>
    <li>Incremental reflow (continued)
	 <ul class=nested>
      <li>reflower not allowed to change available size of reflowee</li>
      <li>reflow commands get coalesced to streamline processing</li> 
	 </ul>
	</li>
    <li>Style change 
	 <ul class=nested>
      <li>a target changed stylistic if there is a target, otherwise every frame may need to respond</li>
      <li>parent of target usually turns it into an incremental reflow with a style changed command type</li> 
	 </ul>
	</li>
  </ul>
</div>

<div class="slide" id="s9">
  <div class="nav">
    <a href="#s8">&lt;</a>
    <a href="#s10">&gt;</a>
  </div>
  <h1>Table Frames</h1>
  <BR>
  <table class="tree" width=90%>
  <tr><td class=frame><td class=space style="width:2%"><td class=frame><td class=space style="width:2%">
      <td class=frame><td class=space><td class=frame></tr>
  <tr><td><td><td class=frame><td>
      <td>nsTableOuter Frame<td><td></tr>
  <tr class="arrows"><td><td><td><td class=left-arrow>&#x2199;<td><td class=right-arrow>&#x2198;</tr>
  <tr><td><td><td>nsTable<BR>Frame<td><td><td><td>nsTableCaption<BR>Frame</tr>
  <tr class="arrows"><td><td class=left-arrow>&#x2199;<td><td class=right-arrow>&#x2198;<td><td><td class=center-arrow>&darr;</tr>
  <tr><td>nsTableCol<BR>GroupFrame<td><td><TD><td>nsTableRow<BR>GroupFrame<td><td>nsBlockFrame</tr>
  <tr class="arrows"><td class=center-arrow>&darr;<td><td><td><td class=center-arrow>&darr;</tr>
  <tr><td>nsTableCol<BR>Frame<td><TD><TD><td>nsTableRow<BR>Frame</tr>
  <tr class="arrows"><td><td><td><td><td class=center-arrow>&darr;</tr>
  <tr><td><td><td><TD><td>nsTableCell<BR>Frame</tr>
  <tr class="arrows"><td><td><td><td><td class=center-arrow>&darr;</tr>
  <tr><td><td><td><TD><td>nsBlock<BR>Frame</tr>
  </table>
</div>

<div class="slide" id="s10">
  <div class="nav">
    <a href="#s9">&lt;</a>
    <a href="#s11">&gt;</a>
  </div>
  <h1>Table Reflow</h1>
  <ul>
    <li>table wrapper reflows table and caption (if present)</li>
	<li>Table reflows row groups in multiple passes</li> 
	 <ul class=nested>
      <li>Pass 1 - unconstrained width, height and requests max elem width.</li>
      <li>The table figures out the column widths (balances) given the style width constraints
	  on the table, col groups, cols, cells the preferred and max element sizes of the cells 
	  (from the pass 1 reflow), and considers colspans</li> 
      <li>Pass 2 - cell widths are constrained by the column widths (heights are only 
	  constrained in paginated mode).</li> 
	 </ul>
	</li>
  </ul>
</div>

<div class="slide" id="s11">
  <div class="nav">
    <a href="#s10">&lt;</a>
    <a href="#s12">&gt;</a>
  </div>
  <h1>Table Reflow</h1>
  <ul>
	<li>Table reflows row groups (continued)</li> 
	 <ul class=nested>
      <li>The row group figures out the row heights given the its style height constraints
	  its rows and cells and the actual heights of its rows and cells from the pass 2 reflow</li> 
      <li>If the table has a style height, it allocates extra height to its row groups, rows and cells.</li> 
	 </ul>
	</li>
    <li>In each pass, row groups reflow rows which reflow cells which reflow cell blocks</li>
  </ul>
</div>

<div class="slide" id="s12">
  <div class="nav">
    <a href="#s11">&lt;</a>
    <a href="#s13">&gt;</a>
  </div>
  <h1>Table Reflow Example</h1>
  <table width=100%>
   <tr>
    <td width=100%>
	 <pre style="font-size:.6em;">
tblW 030176CC r=0 a=8940,UC c=0,0 cnt=429
  tbl 030178C4 r=0 a=8940,UC c=4470,UC cnt=430
   rowG 03017A7C r=0 a=UC,UC c=UC,UC cnt=431 
    row 03017C08 r=0 a=UC,UC c=UC,UC cnt=432
     cell 03017DA8 r=0 a=UC,UC c=UC,UC cnt=433
      block 03017E08 r=0 a=UC,UC c=UC,UC cnt=434
      block 03017E08 d=870,300 me=480
     cell 03017DA8 d=930,360 me=540
     cell 0301A8CC r=0 a=UC,UC c=UC,UC cnt=436
      block 0301A92C r=0 a=UC,UC c=UC,UC cnt=437
      block 0301A92C d=1335,300 me=465
     cell 0301A8CC d=1395,360 me=525
    row 03017C08 d=UC,360
   rowG 03017A7C d=UC,360
   rowG 03017A7C r=2 a=4470,UC c=4470,UC cnt=442
    row 03017C08 r=2 a=4470,UC c=4470,UC cnt=443
     cell 03017DA8 r=2 a=1755,UC c=1695,UC cnt=444
      block 03017E08 r=2 a=1695,UC c=1695,UC cnt=445
      block 03017E08 d=1695,300
     cell 03017DA8 d=1755,360
     cell 0301A8CC r=2 a=2625,UC c=2565,UC cnt=446
      block 0301A92C r=2 a=2565,UC c=2565,UC cnt=447
      block 0301A92C d=2565,300
     cell 0301A8CC d=2625,360
    row 03017C08 d=4470,360
   rowG 03017A7C d=4470,360
  tbl 030178C4 d=4500,450
 tblW 030176CC d=4500,450

 <a href="frame_reflow_debug.html">frame reflow debugging</a> gives instructions 
 for turning this on.
 </pre>
   </td>
   <td>
     <pre style="font-size:.7em;">
&lt;<span class=html>table</span> width=300&gt;
  &lt;<span class=html>tr</span>&gt;
    &lt;<span class=html>td</span>&gt;foo&lt;<span class=html>/td</span>&gt;
    &lt;<span class=html>td</span>&gt;bar zap&lt;<span class=html>/td</span>&gt;
  &lt;<span class=html>/tr</span>&gt;
&lt;<span class=html>/table</span>&gt;
     </pre>
	 <BR>
	 <BR>
	 <pre style="font-size:.7em;">
Key:

  r  = reflow reason, 
       0 (initial),
       2 (resize) 
  a  = avail w, h
  c  = computed w, h
  d  = desired w, h
  me = max elem w
     <pre>
	</td>
  </tr>
 </table>
</div>

<div class="slide" id="s13">
  <div class="nav">
    <a href="#s12">&lt;</a>
    <a href="#s14">&gt;</a>
  </div>
  <h1>Table reflow optimizations</h1>
  <ul>
    <li>If the table is already balanced, pass 1 constrains the width (like a normal pass 2) based on the current
	column widths. The pass 2 will get skipped if the table doesn't need to rebalance. <!--<span class="comment">please clarify when can this happen</span>--></li> 
    <li>Nested table reflowed with an unconstrained width (i.e. an ancestor is doing a pass 1 reflow)
	will only do a pass 1 reflow on its children</li>
    <li>table wrapper caches last avail width and avoids reflowing children if resize reflow is the same as previous</li>
    <li>Table caches max element, preferred widths in case they are requested and it isn't rebalanced</li>
    <li>Cell caches prior avail width. if this doesn't change, the row may not have to reflow the cell</li>
  </ul>

</div>

<div class="slide" id="s14">
  <div class="nav">
    <a href="#s13">&lt;</a>
    <a href="#s15">&gt;</a>
  </div>
  <h1>Table incremental reflow</h1>
  <ul>
    <li>table wrapper is a target when a caption is added or removed (dirty) or the table or caption margin 
  changes (style changed).</li> 
    <li>Caption is a target when it changes stylistically (style changed).</li>
    <li>Table, row group, row, col group, col is a target when a child is added or removed (dirty) or it changes
  stylistically (style changed). <!--<span class="comment">please show how the column style change is propagated 
               into the cell reflows as the cells are reflowed by their parent rows and not cols</span>--></li>
    <li>In the dirty cases, a target posted the reflow command in AppendFrames, InsertFrames, or DeleteFrame.</li>
  </ul>
</div>

<div class="slide" id="s15">
  <div class="nav">
    <a href="#s14">&lt;</a>
    <a href="#s16">&gt;</a>
  </div>
  <h1>Table incremental reflow</h1>
  <ul>
    <li>In the style change cases where a target is between the table and the cell, the table is told to rebalance.</li>
    <li>When a target is the cell or below and the cell changes size, the row tells the table so it can decide if 
  it needs to rebalance</li>
    <li>When a target is inside the cell's block, the cell
  requests max element, preferred sizes of its block in case they change</li>
    <li>After the table reflows the row group(s) containing the targets, if it rebalances, it then does a pass 2 reflow.</li>
  </ul>
</div>

<div class="slide" id="s16">
  <div class="nav">
    <a href="#s15">&lt;</a>
    <a href="#s17">&gt;</a>
  </div>
  <h1>Special height reflow</h1>
  <ul>
    <li>When there is a % height frame inside a cell without a computed height</li>
	  <ul class=nested>
	    <li>the frame will never get a chance to size based on the final cell height</li>
        <li>in paginated mode when there is a height on the table, the table doesn't allocate
		extra height to rows until after it does a pass 2 reflow and then it is too late</li>
	  </ul>
	</li>
    <li>This can be fixed by doing a special 3rd pass reflow</li>
  </ul>
  </div>
</div>

<div class="slide" id="s17">
  <div class="nav">
    <a href="#s16">&lt;</a>
    <a href="#s18">&gt;</a>
  </div>
  <h1>Special Reflow Example</h1>
  <table width=100% style="text-align:left;">
   <tr>
   <td>
     <pre style="font-size:.7em; text-align:left;">
&lt;<span class=html>table</span> border=2 width=300&gt;
  &lt;<span class=html>tr</span>&gt;
    &lt;<span class=html>td</span>&gt;
      This cell's width is 
      constrained by the 
      table and image widths. 
      Its exact height is 
      hard to determine.
    &lt;<span class=html>/td</span>&gt;
    &lt;<span class=html>td</span>&gt;
      &lt;<span class=html>img</span> src=raptor.jpg
       width=200 height=100%>
    &lt;<span class=html>/td</span>&gt;
  &lt;<span class=html>/tr</span>&gt;
&lt;<span class=html>/table</span>&gt;
     </pre>
   </td>
    <td>
	 <table border=2 width=300>
      <tr>
       <td style="font-size:.7em;">This cell's width is constrained 
        by the table and image widths. <BR><BR>Its height
		is hard to determine.<BR><BR> The image needs to be as high as the cell.
       <td>
       <!-- need ?raw=1 for lxr to cough up the image data, not a pretty page -->
       <img src="raptor.jpg?raw=1" 
      width=200 height=100%>
    </td>
   </tr>
  </table>

  </tr>
 </table>
</div>


<div class="slide" id="s18">
  <div class="nav">
    <a href="#s17">&lt;</a>
    <a href="#s19">&gt;</a>
  </div>
  <h1>Special height reflow</h1>
  <ul>
    <li>The reflow state holds an observer and initiator</li>
    <li>Observer</li>
	  <ul class=nested>
	    <li>is the table cell used as the height basis</li>
        <li>set by frame without computed height in DidReflow</li>
        <li>gives its block a computed height during 3rd pass</li>
        <li>doesn't change height during 3rd pass</li>
	  </ul>
	</li>
    <li>Initiator</li>
	  <ul class=nested>
	    <li>is the table containing the observer</li>
        <li>starts the 3rd pass reflow and sets a bit in the reflow state</li>
        <li>gives its block a computed height during 3rd pass</li>
        <li>could also be inside a cell which is an observer</li>
	  </ul>
	</li>
</div>

<div class="slide" id="s19">
  <div class="nav">
    <a href="#s18">&lt;</a>
    <a href="#s20">&gt;</a>
  </div>
  <h1>Special height reflow</h1>
  <ul>
    <li>Optimizations</li>
	  <ul class=nested>
	    <li>only frames needing 3rd pass actually get it</li>
        <li>frames gettting a 3rd pass only get it once</li>
	  </ul>
	</li>
</div>

<div class="slide" id="s20">
  <div class="nav">
    <a href="#s19">&lt;</a>
    <a href="#s21">&gt;</a>
  </div>
  <h1>Intro to paginated reflow</h1>
  <ul>
    <li>When a reflowee's available height is constrained, it may not fit and need to either 
	split/continue on the next page, or start on the next page.</li>
	  <ul class=nested>
	    <li>If it can continue, it returns an incomplete status.</li>
        <li>If it can't continue it returns a complete status.</li>
	  </ul>
	</li>
    <li>A continuation may also need to be continued</li>
    <li>Continuations are linked together by prevInFlow and nextInFlow pointers </li>
  </ul>
</div>

<div class="slide" id="s21">
  <div class="nav">
    <a href="#s20">&lt;</a>
    <a href="#s22">&gt;</a>
  </div>
  <h1>Pagination Illustration</h1>
  <table class=box style="height:500px">
   <tr><td class="title">nsSimplePageSequence</td></tr>
   <tr>
    <td class=box>
	 <table class=box style="height:40%;">
	  <tr><td class=title>nsPageFrame</td></tr>
	  <tr>
	   <td class=box>
	    <table class=box style="height:100%;">
	     <tr><td class=title>nsPageContentFrame</td></tr>
	     <tr>
	      <td class=box style="border-bottom: hidden">
	       <table class=box style="height:100%; border-bottom:hidden">
	        <tr><td class=title>areaFrame (html)</td></tr>
	        <tr>
	         <td class=box>
			  <table class=box style="height:100%; border-bottom:hidden">
	           <tr><td class=title>blockFrame (body)</td></tr>
	           <tr>
	            <td class=box>
			     <table class=box style="height:100%; border-bottom:hidden">
	              <tr><td class=title>nsTableWrapperFrame</td></tr>
	              <tr>
	               <td class=box></td>
	              </tr>
	             </table>
				</td>
	           </tr>
	          </table>
             </td>
	        </tr>
	       </table>
	     </tr>
	    </table>
	   </td>
	  </tr>
	 </table>
	 <BR>
	 <table class=box style="height:40%;">
	  <tr>
	   <td class=box>
	    <table class=box style="height:100%;">
	     <tr>
	      <td class=box style="border-top: hidden">
	       <table class=box style="height:100%; border-top:hidden">
	        <tr>
	         <td class=box>
			  <table class=box style="height:100%; border-top:hidden">
	           <tr>
	            <td class=box>
			     <table class=box style="height:100%; border-top:hidden">
	              <tr>
	               <td class=box></td>
	              </tr>
	              <tr><td class=title2>nsTableWrapperFrame</td></tr>
	             </table>
				</td>
	           </tr>
	           <tr><td class=title2>blockFrame (body)</td></tr>
	          </table>
             </td>
	        </tr>
	        <tr><td class=title2>areaFrame (html)</td></tr>
	       </table>
	     </tr>
	     <tr><td class=title2>nsPageContentFrame continued</td></tr>
	    </table>
	   </td>
	  </tr>
	  <tr><td class=title2>nsPageFrame continued</td></tr>
	 </table>
	</td>
   </tr>
  </table>
</div>

<div class="slide" id="s22">
  <div class="nav">
    <a href="#s21">&lt;</a>
    <a href="#s23">&gt;</a>
  </div>
  <h1>Intro to paginated reflow</h1>
  <ul>
    <li>The page sequence starts with one page and reflows it. If the page is incomplete then the page sequence
        creates a continuation for the page and sets it as the page's next sibling (it is also the page's 
		nextInFlow).</li>
    <li>The page was incomplete because the page content was incomplete because the doc root was incomplete</li>
    <li>The doc root was incomplete because it contained lines that didn't fit (or if it was mapped to a table, 
	    because the table didn't fit) becacause a line contained something that didn't fit, etc.</li>
  </ul>
</div>

<div class="slide" id="s23">
  <div class="nav">
    <a href="#s22">&lt;</a>
    <a href="#s24">&gt;</a>
  </div>
  <h1>Intro to paginated reflow</h1>
  <ul>
    <li>If the reflowee is incomplete, the reflower has the responsiblity to:
	  <ul>
	    <li>Create a continuation for the reflowee</li>
	    <li>Ensure that the continuation gets put in the frame hierarchy at the right place
		and gets reflowed at the right time.</li>
	    <li>Typically, a reflower accomplishes this by putting the continuation (c) on an overflow 
		list which the reflower owns. When the reflower's continuation gets reflowed, it takes c 
		and its siblings as children and reflows them.</li>
	  </ul>
	</li>
    <li>If the reflowee is complete, truncated (it didn't fit), not at the top of page, 
    the reflower should put the reflowee on its overflow list and return an incomplete status.</li>
  </ul>
</div>

<div class="slide" id="s24">
  <div class="nav">
    <a href="#s23">&lt;</a>
    <a href="#s25">&gt;</a>
  </div>
  <h1>Intro to paginated reflow</h1>
  <ul>
    <li>Special assumptions
	  <ul>
	    <li>There are only initial and (possibly) resize reflows. Incremental 
		and style change reflows are not allowed.</li>
	    <li>Multiple resize reflows may be necessary (e.g. a child is truncated and gets reflowed on a 
		subsequent page) but they should not change the available width from the last time.</li>
	    <li>Multiple resize reflows may require special handling if a frame split previously. It may need
		to "pull up" children from a continuation.</li>
	  </ul>
	</li>
  </ul>
</div>

<div class="slide" id="s25">
  <div class="nav">
    <a href="#s24">&lt;</a>
    <a href="#s26">&gt;</a>
  </div>
  <h1>Table paginated reflow</h1>
  <ul>
	<li>The block containing the table wrapper reflows it. If it is incomplete, the block will
	  <ul>
	    <li>create a continuation for the table wrapper (which also creates a continuation for the table).</li>
	    <li>put the continuation on a new line and place that line on its overflow lines property.</li>
	  </ul>
	</li>
    <li>The table wrapper reflows the table and just returns the status of the table.</li>
    <li>The table does a pass 1 reflow and balances. If it is incomplete,</li>
	  <ul>
	    <li>it will become the first-in-flow</li>
		<li>it will be the only frame among its continuations to ever balance or calc the cell map, and it only
		does this once</li>
	  </ul>
	</li>
  </ul>
</div>

<div class="slide" id="s26">
  <div class="nav">
    <a href="#s25">&lt;</a>
    <a href="#s27">&gt;</a>
  </div>
  <h1>Table paginated reflow</h1>
  <ul>
	<li>The table does a pass 2 reflow constraining both avail heights and widths. If a row group is incomplete, the table
	  <ul>
	    <li>creates a continuation for the row group</li>
	    <li>puts the continuation in its overflow frames property</li>
	  </ul>
	</li>
    <li>What follows only applies during the pass 2 reflow.</li>
    <li>The row group</li>
	  <ul>
	    <li>reflows all of its rows with unconstrained heights and calculates the row heights,</li>
		<li>figures out which row falls on a page boundary and reflows it with a constrained height. If there
        will be a pass 3 reflow then this should (bug) happen at that time instead.</li>
	  </ul>
	</li>
  </ul>
</div>

<div class="slide" id="s27">
  <div class="nav">
    <a href="#s26">&lt;</a>
    <a href="#s28">&gt;</a>
  </div>
  <h1>Table paginated reflow</h1>
  <ul>
    <li>The row group (continued)</li>
	  <ul>
		<li>creates a continuation for the incomplete row (which also creates continuations for all of its cells
        and all of the cell blocks)</li>
		<li>puts the continuation in its overflow frames property. If the row was truncated and not top of page,
		the row is put in the overflow frames property.
	  </ul>
	</li>
  </ul>
</div>

<div class="slide" id="s28">
  <div class="nav">
    <a href="#s27">&lt;</a>
    <a href="#s0">&gt;</a>
  </div>
  <h1>Table paginated reflow</h1>
  <ul>
	<li>The row and cells (getting the constrained height reflow) just reflow their children with a constrained height.  
    They don't need an overflow list for continued children because the continuations were created when the
    row group created the row's continutation.</li>
    <li>A cell is incomplete because its block is incomplete. The block uses the overflow lines mechanism 
    (mentioned above) for its continued children</li>
	</li>
	<li>There are two splitting scenarios for a table
	  <ul>
	    <li>An incomplete cells block causes the cell, row, row group, table, table wrapper to
	    be incomplete</li>
	    <li>A truncated row or a row that started too far down the page causes the row group, 
		table, table wrapper to be incomplete.</li>
	  </ul>
	</li>
  </ul>
</div>


</body>
</html>