summaryrefslogtreecommitdiffstats
path: root/layout/mathml/nsMathMLmoFrame.cpp
blob: 591b46309a1e0e9e737ab24c3679856ab444f9a3 (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
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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/. */

#include "nsMathMLmoFrame.h"
#include "nsPresContext.h"
#include "nsRenderingContext.h"
#include "nsContentUtils.h"
#include "nsFrameSelection.h"
#include "nsMathMLElement.h"
#include <algorithm>

//
// <mo> -- operator, fence, or separator - implementation
//

// additional style context to be used by our MathMLChar.
#define NS_MATHML_CHAR_STYLE_CONTEXT_INDEX   0

nsIFrame*
NS_NewMathMLmoFrame(nsIPresShell* aPresShell, nsStyleContext *aContext)
{
  return new (aPresShell) nsMathMLmoFrame(aContext);
}

NS_IMPL_FRAMEARENA_HELPERS(nsMathMLmoFrame)

nsMathMLmoFrame::~nsMathMLmoFrame()
{
}

static const char16_t kApplyFunction  = char16_t(0x2061);
static const char16_t kInvisibleTimes = char16_t(0x2062);
static const char16_t kInvisibleSeparator = char16_t(0x2063);
static const char16_t kInvisiblePlus = char16_t(0x2064);

eMathMLFrameType
nsMathMLmoFrame::GetMathMLFrameType()
{
  return NS_MATHML_OPERATOR_IS_INVISIBLE(mFlags)
    ? eMathMLFrameType_OperatorInvisible
    : eMathMLFrameType_OperatorOrdinary;
}

// since a mouse click implies selection, we cannot just rely on the
// frame's state bit in our child text frame. So we will first check
// its selected state bit, and use this little helper to double check.
bool
nsMathMLmoFrame::IsFrameInSelection(nsIFrame* aFrame)
{
  NS_ASSERTION(aFrame, "null arg");
  if (!aFrame || !aFrame->IsSelected())
    return false;

  const nsFrameSelection* frameSelection = aFrame->GetConstFrameSelection();
  SelectionDetails* details =
    frameSelection->LookUpSelection(aFrame->GetContent(), 0, 1, true);

  if (!details)
    return false;

  while (details) {
    SelectionDetails* next = details->mNext;
    delete details;
    details = next;
  }
  return true;
}

bool
nsMathMLmoFrame::UseMathMLChar()
{
  return (NS_MATHML_OPERATOR_GET_FORM(mFlags) &&
          NS_MATHML_OPERATOR_IS_MUTABLE(mFlags)) ||
    NS_MATHML_OPERATOR_IS_CENTERED(mFlags);
}

void
nsMathMLmoFrame::BuildDisplayList(nsDisplayListBuilder*   aBuilder,
                                  const nsRect&           aDirtyRect,
                                  const nsDisplayListSet& aLists)
{
  bool useMathMLChar = UseMathMLChar();

  if (!useMathMLChar) {
    // let the base class do everything
    nsMathMLTokenFrame::BuildDisplayList(aBuilder, aDirtyRect, aLists);
  } else {
    DisplayBorderBackgroundOutline(aBuilder, aLists);
    
    // make our char selected if our inner child text frame is selected
    bool isSelected = false;
    nsRect selectedRect;
    nsIFrame* firstChild = mFrames.FirstChild();
    if (IsFrameInSelection(firstChild)) {
      mMathMLChar.GetRect(selectedRect);
      // add a one pixel border (it renders better for operators like minus)
      selectedRect.Inflate(nsPresContext::CSSPixelsToAppUnits(1));
      isSelected = true;
    }
    mMathMLChar.Display(aBuilder, this, aLists, 0, isSelected ? &selectedRect : nullptr);
  
#if defined(DEBUG) && defined(SHOW_BOUNDING_BOX)
    // for visual debug
    DisplayBoundingMetrics(aBuilder, this, mReference, mBoundingMetrics, aLists);
#endif
  }
}

// get the text that we enclose and setup our nsMathMLChar
void
nsMathMLmoFrame::ProcessTextData()
{
  mFlags = 0;

  nsAutoString data;
  nsContentUtils::GetNodeTextContent(mContent, false, data);

  data.CompressWhitespace();
  int32_t length = data.Length();
  char16_t ch = (length == 0) ? char16_t('\0') : data[0];

  if ((length == 1) && 
      (ch == kApplyFunction  ||
       ch == kInvisibleSeparator ||
       ch == kInvisiblePlus ||
       ch == kInvisibleTimes)) {
    mFlags |= NS_MATHML_OPERATOR_INVISIBLE;
  }

  // don't bother doing anything special if we don't have a single child
  nsPresContext* presContext = PresContext();
  if (mFrames.GetLength() != 1) {
    data.Truncate(); // empty data to reset the char
    mMathMLChar.SetData(data);
    ResolveMathMLCharStyle(presContext, mContent, mStyleContext, &mMathMLChar);
    return;
  }

  // special... in math mode, the usual minus sign '-' looks too short, so
  // what we do here is to remap <mo>-</mo> to the official Unicode minus
  // sign (U+2212) which looks much better. For background on this, see
  // http://groups.google.com/groups?hl=en&th=66488daf1ade7635&rnum=1
  if (1 == length && ch == '-') {
    ch = 0x2212;
    data = ch;
  }

  // cache the special bits: mutable, accent, movablelimits, centered.
  // we need to do this in anticipation of other requirements, and these
  // bits don't change. Do not reset these bits unless the text gets changed.

  // lookup all the forms under which the operator is listed in the dictionary,
  // and record whether the operator has accent="true" or movablelimits="true"
  nsOperatorFlags flags[4];
  float lspace[4], rspace[4];
  nsMathMLOperators::LookupOperators(data, flags, lspace, rspace);
  nsOperatorFlags allFlags =
    flags[NS_MATHML_OPERATOR_FORM_INFIX] |
    flags[NS_MATHML_OPERATOR_FORM_POSTFIX] |
    flags[NS_MATHML_OPERATOR_FORM_PREFIX];

  mFlags |= allFlags & NS_MATHML_OPERATOR_ACCENT;
  mFlags |= allFlags & NS_MATHML_OPERATOR_MOVABLELIMITS;

  // see if this is an operator that should be centered to cater for 
  // fonts that are not math-aware
  if (1 == length) {
    if ((ch == '+') || (ch == '=') || (ch == '*') ||
        (ch == 0x2212) || // &minus;
        (ch == 0x2264) || // &le;
        (ch == 0x2265) || // &ge;
        (ch == 0x00D7)) { // &times;
      mFlags |= NS_MATHML_OPERATOR_CENTERED;
    }
  }

  // cache the operator
  mMathMLChar.SetData(data);

  // cache the native direction -- beware of bug 133429...
  // mEmbellishData.direction must always retain our native direction, whereas
  // mMathMLChar.GetStretchDirection() may change later, when Stretch() is called
  mEmbellishData.direction = mMathMLChar.GetStretchDirection();

  bool isMutable =
    NS_MATHML_OPERATOR_IS_LARGEOP(allFlags) ||
    (mEmbellishData.direction != NS_STRETCH_DIRECTION_UNSUPPORTED);
  if (isMutable)
    mFlags |= NS_MATHML_OPERATOR_MUTABLE;

  ResolveMathMLCharStyle(presContext, mContent, mStyleContext, &mMathMLChar);
}

// get our 'form' and lookup in the Operator Dictionary to fetch 
// our default data that may come from there. Then complete our setup
// using attributes that we may have. To stay in sync, this function is
// called very often. We depend on many things that may change around us.
// However, we re-use unchanged values.
void
nsMathMLmoFrame::ProcessOperatorData()
{
  // if we have been here before, we will just use our cached form
  nsOperatorFlags form = NS_MATHML_OPERATOR_GET_FORM(mFlags);
  nsAutoString value;
  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);

  // special bits are always kept in mFlags.
  // remember the mutable bit from ProcessTextData().
  // Some chars are listed under different forms in the dictionary,
  // and there could be a form under which the char is mutable.
  // If the char is the core of an embellished container, we will keep
  // it mutable irrespective of the form of the embellished container.
  // Also remember the other special bits that we want to carry forward.
  mFlags &= NS_MATHML_OPERATOR_MUTABLE |
            NS_MATHML_OPERATOR_ACCENT | 
            NS_MATHML_OPERATOR_MOVABLELIMITS |
            NS_MATHML_OPERATOR_CENTERED |
            NS_MATHML_OPERATOR_INVISIBLE;

  if (!mEmbellishData.coreFrame) {
    // i.e., we haven't been here before, the default form is infix
    form = NS_MATHML_OPERATOR_FORM_INFIX;

    // reset everything so that we don't keep outdated values around
    // in case of dynamic changes
    mEmbellishData.flags = 0;
    mEmbellishData.coreFrame = nullptr;
    mEmbellishData.leadingSpace = 0;
    mEmbellishData.trailingSpace = 0;
    if (mMathMLChar.Length() != 1)
      mEmbellishData.direction = NS_STRETCH_DIRECTION_UNSUPPORTED;  
    // else... retain the native direction obtained in ProcessTextData()

    if (!mFrames.FirstChild()) {
      return;
    }

    mEmbellishData.flags |= NS_MATHML_EMBELLISH_OPERATOR;
    mEmbellishData.coreFrame = this;

    // there are two particular things that we also need to record so that if our
    // parent is <mover>, <munder>, or <munderover>, they will treat us properly:
    // 1) do we have accent="true"
    // 2) do we have movablelimits="true"

    // they need the extra information to decide how to treat their scripts/limits
    // (note: <mover>, <munder>, or <munderover> need not necessarily be our
    // direct parent -- case of embellished operators)

    // default values from the Operator Dictionary were obtained in ProcessTextData()
    // and these special bits are always kept in mFlags
    if (NS_MATHML_OPERATOR_IS_ACCENT(mFlags))
      mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENT;
    if (NS_MATHML_OPERATOR_IS_MOVABLELIMITS(mFlags))
      mEmbellishData.flags |= NS_MATHML_EMBELLISH_MOVABLELIMITS;

    // see if the accent attribute is there
    mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::accent_, value);
    if (value.EqualsLiteral("true"))
      mEmbellishData.flags |= NS_MATHML_EMBELLISH_ACCENT;
    else if (value.EqualsLiteral("false"))
      mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_ACCENT;

    // see if the movablelimits attribute is there
    mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::movablelimits_, value);
    if (value.EqualsLiteral("true"))
      mEmbellishData.flags |= NS_MATHML_EMBELLISH_MOVABLELIMITS;
    else if (value.EqualsLiteral("false"))
      mEmbellishData.flags &= ~NS_MATHML_EMBELLISH_MOVABLELIMITS;

     // ---------------------------------------------------------------------
     // we will be called again to re-sync the rest of our state next time...
     // (nobody needs the other values below at this stage)
     mFlags |= form;
     return;
  }

  nsPresContext* presContext = PresContext();

  // beware of bug 133814 - there is a two-way dependency in the
  // embellished hierarchy: our embellished ancestors need to set
  // their flags based on some of our state (set above), and here we
  // need to re-sync our 'form' depending on our outermost embellished
  // container. A null form here means that an earlier attempt to stretch
  // our mMathMLChar failed, in which case we don't bother re-stretching again
  if (form) {
    // get our outermost embellished container and its parent. 
    // (we ensure that we are the core, not just a sibling of the core)
    nsIFrame* embellishAncestor = this;
    nsEmbellishData embellishData;
    nsIFrame* parentAncestor = this;
    do {
      embellishAncestor = parentAncestor;
      parentAncestor = embellishAncestor->GetParent();
      GetEmbellishDataFrom(parentAncestor, embellishData);
    } while (embellishData.coreFrame == this);

    // flag if we have an embellished ancestor
    if (embellishAncestor != this)
      mFlags |= NS_MATHML_OPERATOR_EMBELLISH_ANCESTOR;
    else
      mFlags &= ~NS_MATHML_OPERATOR_EMBELLISH_ANCESTOR;

    // find the position of our outermost embellished container w.r.t
    // its siblings.

    nsIFrame* nextSibling = embellishAncestor->GetNextSibling();
    nsIFrame* prevSibling = embellishAncestor->GetPrevSibling();

    // flag to distinguish from a real infix.  Set for (embellished) operators
    // that live in (inferred) mrows.
    nsIMathMLFrame* mathAncestor = do_QueryFrame(parentAncestor);
    bool zeroSpacing = false;
    if (mathAncestor) {
      zeroSpacing =  !mathAncestor->IsMrowLike();
    } else {
      nsMathMLmathBlockFrame* blockFrame = do_QueryFrame(parentAncestor);
      if (blockFrame) {
        zeroSpacing = !blockFrame->IsMrowLike();
      }
    }
    if (zeroSpacing) {
      mFlags |= NS_MATHML_OPERATOR_EMBELLISH_ISOLATED;
    } else {
      mFlags &= ~NS_MATHML_OPERATOR_EMBELLISH_ISOLATED;
    }

    // find our form
    form = NS_MATHML_OPERATOR_FORM_INFIX;
    mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::form, value);
    if (!value.IsEmpty()) {
      if (value.EqualsLiteral("prefix"))
        form = NS_MATHML_OPERATOR_FORM_PREFIX;
      else if (value.EqualsLiteral("postfix"))
        form = NS_MATHML_OPERATOR_FORM_POSTFIX;
    }
    else {
      // set our form flag depending on the position
      if (!prevSibling && nextSibling)
        form = NS_MATHML_OPERATOR_FORM_PREFIX;
      else if (prevSibling && !nextSibling)
        form = NS_MATHML_OPERATOR_FORM_POSTFIX;
    }
    mFlags &= ~NS_MATHML_OPERATOR_FORM; // clear the old form bits
    mFlags |= form;

    // Use the default value suggested by the MathML REC.
    // http://www.w3.org/TR/MathML/chapter3.html#presm.mo.attrs
    // thickmathspace = 5/18em
    float lspace = 5.0f/18.0f;
    float rspace = 5.0f/18.0f;
    // lookup the operator dictionary
    nsAutoString data;
    mMathMLChar.GetData(data);
    nsMathMLOperators::LookupOperator(data, form, &mFlags, &lspace, &rspace);
    // Spacing is zero if our outermost embellished operator is not in an
    // inferred mrow.
    if (!NS_MATHML_OPERATOR_EMBELLISH_IS_ISOLATED(mFlags) &&
        (lspace || rspace)) {
      // Cache the default values of lspace and rspace.
      // since these values are relative to the 'em' unit, convert to twips now
      nscoord em;
      RefPtr<nsFontMetrics> fm =
        nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
      GetEmHeight(fm, em);

      mEmbellishData.leadingSpace = NSToCoordRound(lspace * em);
      mEmbellishData.trailingSpace = NSToCoordRound(rspace * em);

      // tuning if we don't want too much extra space when we are a script.
      // (with its fonts, TeX sets lspace=0 & rspace=0 as soon as scriptlevel>0.
      // Our fonts can be anything, so...)
      if (StyleFont()->mScriptLevel > 0 &&
          !NS_MATHML_OPERATOR_HAS_EMBELLISH_ANCESTOR(mFlags)) {
        mEmbellishData.leadingSpace /= 2;
        mEmbellishData.trailingSpace /= 2;
      }
    }
  }

  // If we are an accent without explicit lspace="." or rspace=".",
  // we will ignore our default leading/trailing space

  // lspace
  //
  // "Specifies the leading space appearing before the operator"
  //
  // values: length
  // default: set by dictionary (thickmathspace) 
  //
  // XXXfredw Support for negative and relative values is not implemented
  // (bug 805926).
  // Relative values will give a multiple of the current leading space,
  // which is not necessarily the default one.
  //
  nscoord leadingSpace = mEmbellishData.leadingSpace;
  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::lspace_, value);
  if (!value.IsEmpty()) {
    nsCSSValue cssValue;
    if (nsMathMLElement::ParseNumericValue(value, cssValue, 0,
                                           mContent->OwnerDoc())) {
      if ((eCSSUnit_Number == cssValue.GetUnit()) && !cssValue.GetFloatValue())
        leadingSpace = 0;
      else if (cssValue.IsLengthUnit())
        leadingSpace = CalcLength(presContext, mStyleContext, cssValue,
                                  fontSizeInflation);
      mFlags |= NS_MATHML_OPERATOR_LSPACE_ATTR;
    }
  }

  // rspace
  //
  // "Specifies the trailing space appearing after the operator"
  //
  // values: length
  // default: set by dictionary (thickmathspace) 
  //
  // XXXfredw Support for negative and relative values is not implemented
  // (bug 805926).
  // Relative values will give a multiple of the current leading space,
  // which is not necessarily the default one.
  //
  nscoord trailingSpace = mEmbellishData.trailingSpace;
  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::rspace_, value);
  if (!value.IsEmpty()) {
    nsCSSValue cssValue;
    if (nsMathMLElement::ParseNumericValue(value, cssValue, 0,
                                           mContent->OwnerDoc())) {
      if ((eCSSUnit_Number == cssValue.GetUnit()) && !cssValue.GetFloatValue())
        trailingSpace = 0;
      else if (cssValue.IsLengthUnit())
        trailingSpace = CalcLength(presContext, mStyleContext, cssValue,
                                   fontSizeInflation);
      mFlags |= NS_MATHML_OPERATOR_RSPACE_ATTR;
    }
  }

  // little extra tuning to round lspace & rspace to at least a pixel so that
  // operators don't look as if they are colliding with their operands
  if (leadingSpace || trailingSpace) {
    nscoord onePixel = nsPresContext::CSSPixelsToAppUnits(1);
    if (leadingSpace && leadingSpace < onePixel)
      leadingSpace = onePixel;
    if (trailingSpace && trailingSpace < onePixel)
      trailingSpace = onePixel;
  }

  // the values that we get from our attributes override the dictionary
  mEmbellishData.leadingSpace = leadingSpace;
  mEmbellishData.trailingSpace = trailingSpace;

  // Now see if there are user-defined attributes that override the dictionary.
  // XXX Bug 1197771 - forcing an attribute to true when it is false in the
  // dictionary can cause conflicts in the rest of the stretching algorithms
  // (e.g. all largeops are assumed to have a vertical direction)

  // For each attribute overriden by the user, turn off its bit flag.
  // symmetric|movablelimits|separator|largeop|accent|fence|stretchy|form
  // special: accent and movablelimits are handled above,
  // don't process them here

  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::stretchy_, value);
  if (value.EqualsLiteral("false")) {
    mFlags &= ~NS_MATHML_OPERATOR_STRETCHY;
  } else if (value.EqualsLiteral("true")) {
    mFlags |= NS_MATHML_OPERATOR_STRETCHY;
  }
  if (NS_MATHML_OPERATOR_IS_FENCE(mFlags)) {
    mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::fence_, value);
    if (value.EqualsLiteral("false"))
      mFlags &= ~NS_MATHML_OPERATOR_FENCE;
    else
      mEmbellishData.flags |= NS_MATHML_EMBELLISH_FENCE;
  }
  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::largeop_, value);
  if (value.EqualsLiteral("false")) {
    mFlags &= ~NS_MATHML_OPERATOR_LARGEOP;
  } else if (value.EqualsLiteral("true")) {
    mFlags |= NS_MATHML_OPERATOR_LARGEOP;
  }
  if (NS_MATHML_OPERATOR_IS_SEPARATOR(mFlags)) {
    mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::separator_, value);
    if (value.EqualsLiteral("false"))
      mFlags &= ~NS_MATHML_OPERATOR_SEPARATOR;
    else
      mEmbellishData.flags |= NS_MATHML_EMBELLISH_SEPARATOR;
  }
  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::symmetric_, value);
  if (value.EqualsLiteral("false"))
    mFlags &= ~NS_MATHML_OPERATOR_SYMMETRIC;
  else if (value.EqualsLiteral("true"))
    mFlags |= NS_MATHML_OPERATOR_SYMMETRIC;


  // minsize
  //
  // "Specifies the minimum size of the operator when stretchy"
  //
  // values: length
  // default: set by dictionary (1em)
  //
  // We don't allow negative values.
  // Note: Contrary to other "length" values, unitless and percentage do not
  // give a multiple of the defaut value but a multiple of the operator at
  // normal size.
  //
  mMinSize = 0;
  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::minsize_, value);
  if (!value.IsEmpty()) {
    nsCSSValue cssValue;
    if (nsMathMLElement::ParseNumericValue(value, cssValue,
                                           nsMathMLElement::
                                           PARSE_ALLOW_UNITLESS,
                                           mContent->OwnerDoc())) {
      nsCSSUnit unit = cssValue.GetUnit();
      if (eCSSUnit_Number == unit)
        mMinSize = cssValue.GetFloatValue();
      else if (eCSSUnit_Percent == unit)
        mMinSize = cssValue.GetPercentValue();
      else if (eCSSUnit_Null != unit) {
        mMinSize = float(CalcLength(presContext, mStyleContext, cssValue,
                                    fontSizeInflation));
        mFlags |= NS_MATHML_OPERATOR_MINSIZE_ABSOLUTE;
      }
    }
  }

  // maxsize
  //
  // "Specifies the maximum size of the operator when stretchy"
  //
  // values: length | "infinity"
  // default: set by dictionary (infinity)
  //
  // We don't allow negative values.
  // Note: Contrary to other "length" values, unitless and percentage do not
  // give a multiple of the defaut value but a multiple of the operator at
  // normal size.
  //
  mMaxSize = NS_MATHML_OPERATOR_SIZE_INFINITY;
  mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::maxsize_, value);
  if (!value.IsEmpty()) {
    nsCSSValue cssValue;
    if (nsMathMLElement::ParseNumericValue(value, cssValue,
                                           nsMathMLElement::
                                           PARSE_ALLOW_UNITLESS,
                                           mContent->OwnerDoc())) {
      nsCSSUnit unit = cssValue.GetUnit();
      if (eCSSUnit_Number == unit)
        mMaxSize = cssValue.GetFloatValue();
      else if (eCSSUnit_Percent == unit)
        mMaxSize = cssValue.GetPercentValue();
      else if (eCSSUnit_Null != unit) {
        mMaxSize = float(CalcLength(presContext, mStyleContext, cssValue,
                                    fontSizeInflation));
        mFlags |= NS_MATHML_OPERATOR_MAXSIZE_ABSOLUTE;
      }
    }
  }
}

static uint32_t
GetStretchHint(nsOperatorFlags aFlags, nsPresentationData aPresentationData,
               bool aIsVertical, const nsStyleFont* aStyleFont)
{
  uint32_t stretchHint = NS_STRETCH_NONE;
  // See if it is okay to stretch,
  // starting from what the Operator Dictionary said
  if (NS_MATHML_OPERATOR_IS_MUTABLE(aFlags)) {
    // set the largeop or largeopOnly flags to suitably cover all the
    // 8 possible cases depending on whether displaystyle, largeop,
    // stretchy are true or false (see bug 69325).
    // . largeopOnly is taken if largeop=true and stretchy=false
    // . largeop is taken if largeop=true and stretchy=true
    if (aStyleFont->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK &&
        NS_MATHML_OPERATOR_IS_LARGEOP(aFlags)) {
      stretchHint = NS_STRETCH_LARGEOP; // (largeopOnly, not mask!)
      if (NS_MATHML_OPERATOR_IS_INTEGRAL(aFlags)) {
        stretchHint |= NS_STRETCH_INTEGRAL;
      }
      if (NS_MATHML_OPERATOR_IS_STRETCHY(aFlags)) {
        stretchHint |= NS_STRETCH_NEARER | NS_STRETCH_LARGER;
      }
    }
    else if(NS_MATHML_OPERATOR_IS_STRETCHY(aFlags)) {
      if (aIsVertical) {
        // TeX hint. Can impact some sloppy markups missing <mrow></mrow>
        stretchHint = NS_STRETCH_NEARER;
      }
      else {
        stretchHint = NS_STRETCH_NORMAL;
      }
    }
    // else if the stretchy and largeop attributes have been disabled,
    // the operator is not mutable
  }
  return stretchHint;
}

// NOTE: aDesiredStretchSize is an IN/OUT parameter
//       On input  - it contains our current size
//       On output - the same size or the new size that we want
NS_IMETHODIMP
nsMathMLmoFrame::Stretch(DrawTarget*          aDrawTarget,
                         nsStretchDirection   aStretchDirection,
                         nsBoundingMetrics&   aContainerSize,
                         ReflowOutput& aDesiredStretchSize)
{
  if (NS_MATHML_STRETCH_WAS_DONE(mPresentationData.flags)) {
    NS_WARNING("it is wrong to fire stretch more than once on a frame");
    return NS_OK;
  }
  mPresentationData.flags |= NS_MATHML_STRETCH_DONE;

  nsIFrame* firstChild = mFrames.FirstChild();

  // get the axis height;
  float fontSizeInflation = nsLayoutUtils::FontSizeInflationFor(this);
  RefPtr<nsFontMetrics> fm =
    nsLayoutUtils::GetFontMetricsForFrame(this, fontSizeInflation);
  nscoord axisHeight, height;
  GetAxisHeight(aDrawTarget, fm, axisHeight);

  // get the leading to be left at the top and the bottom of the stretched char
  // this seems more reliable than using fm->GetLeading() on suspicious fonts
  nscoord em;
  GetEmHeight(fm, em);
  nscoord leading = NSToCoordRound(0.2f * em);

  // Operators that are stretchy, or those that are to be centered
  // to cater for fonts that are not math-aware, are handled by the MathMLChar
  // ('form' is reset if stretch fails -- i.e., we don't bother to stretch next time)
  bool useMathMLChar = UseMathMLChar();

  nsBoundingMetrics charSize;
  nsBoundingMetrics container = aDesiredStretchSize.mBoundingMetrics;
  bool isVertical = false;

  if (((aStretchDirection == NS_STRETCH_DIRECTION_VERTICAL) ||
       (aStretchDirection == NS_STRETCH_DIRECTION_DEFAULT))  &&
      (mEmbellishData.direction == NS_STRETCH_DIRECTION_VERTICAL)) {
    isVertical = true;
  }

  uint32_t stretchHint =
    GetStretchHint(mFlags, mPresentationData, isVertical, StyleFont());

  if (useMathMLChar) {
    nsBoundingMetrics initialSize = aDesiredStretchSize.mBoundingMetrics;

    if (stretchHint != NS_STRETCH_NONE) {

      container = aContainerSize;

      // some adjustments if the operator is symmetric and vertical

      if (isVertical && NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags)) {
        // we need to center about the axis
        nscoord delta = std::max(container.ascent - axisHeight,
                               container.descent + axisHeight);
        container.ascent = delta + axisHeight;
        container.descent = delta - axisHeight;

        // get ready in case we encounter user-desired min-max size
        delta = std::max(initialSize.ascent - axisHeight,
                       initialSize.descent + axisHeight);
        initialSize.ascent = delta + axisHeight;
        initialSize.descent = delta - axisHeight;
      }

      // check for user-desired min-max size

      if (mMaxSize != NS_MATHML_OPERATOR_SIZE_INFINITY && mMaxSize > 0.0f) {
        // if we are here, there is a user defined maxsize ...
        //XXX Set stretchHint = NS_STRETCH_NORMAL? to honor the maxsize as close as possible?
        if (NS_MATHML_OPERATOR_MAXSIZE_IS_ABSOLUTE(mFlags)) {
          // there is an explicit value like maxsize="20pt"
          // try to maintain the aspect ratio of the char
          float aspect = mMaxSize / float(initialSize.ascent + initialSize.descent);
          container.ascent =
            std::min(container.ascent, nscoord(initialSize.ascent * aspect));
          container.descent =
            std::min(container.descent, nscoord(initialSize.descent * aspect));
          // below we use a type cast instead of a conversion to avoid a VC++ bug
          // see http://support.microsoft.com/support/kb/articles/Q115/7/05.ASP
          container.width =
            std::min(container.width, (nscoord)mMaxSize);
        }
        else { // multiplicative value
          container.ascent =
            std::min(container.ascent, nscoord(initialSize.ascent * mMaxSize));
          container.descent =
            std::min(container.descent, nscoord(initialSize.descent * mMaxSize));
          container.width =
            std::min(container.width, nscoord(initialSize.width * mMaxSize));
        }

        if (isVertical && !NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags)) {
          // re-adjust to align the char with the bottom of the initial container
          height = container.ascent + container.descent;
          container.descent = aContainerSize.descent;
          container.ascent = height - container.descent;
        }
      }

      if (mMinSize > 0.0f) {
        // if we are here, there is a user defined minsize ...
        // always allow the char to stretch in its natural direction,
        // even if it is different from the caller's direction 
        if (aStretchDirection != NS_STRETCH_DIRECTION_DEFAULT &&
            aStretchDirection != mEmbellishData.direction) {
          aStretchDirection = NS_STRETCH_DIRECTION_DEFAULT;
          // but when we are not honoring the requested direction
          // we should not use the caller's container size either
          container = initialSize;
        }
        if (NS_MATHML_OPERATOR_MINSIZE_IS_ABSOLUTE(mFlags)) {
          // there is an explicit value like minsize="20pt"
          // try to maintain the aspect ratio of the char
          float aspect = mMinSize / float(initialSize.ascent + initialSize.descent);
          container.ascent =
            std::max(container.ascent, nscoord(initialSize.ascent * aspect));
          container.descent =
            std::max(container.descent, nscoord(initialSize.descent * aspect));
          container.width =
            std::max(container.width, (nscoord)mMinSize);
        }
        else { // multiplicative value
          container.ascent =
            std::max(container.ascent, nscoord(initialSize.ascent * mMinSize));
          container.descent =
            std::max(container.descent, nscoord(initialSize.descent * mMinSize));
          container.width =
            std::max(container.width, nscoord(initialSize.width * mMinSize));
        }

        if (isVertical && !NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags)) {
          // re-adjust to align the char with the bottom of the initial container
          height = container.ascent + container.descent;
          container.descent = aContainerSize.descent;
          container.ascent = height - container.descent;
        }
      }
    }

    // let the MathMLChar stretch itself...
    nsresult res = mMathMLChar.Stretch(PresContext(), aDrawTarget,
                                       fontSizeInflation,
                                       aStretchDirection, container, charSize,
                                       stretchHint,
                                       StyleVisibility()->mDirection);
    if (NS_FAILED(res)) {
      // gracefully handle cases where stretching the char failed (i.e., GetBoundingMetrics failed)
      // clear our 'form' to behave as if the operator wasn't in the dictionary
      mFlags &= ~NS_MATHML_OPERATOR_FORM;
      useMathMLChar = false;
    }
  }

  // Place our children using the default method
  // This will allow our child text frame to get its DidReflow()
  nsresult rv = Place(aDrawTarget, true, aDesiredStretchSize);
  if (NS_MATHML_HAS_ERROR(mPresentationData.flags) || NS_FAILED(rv)) {
    // Make sure the child frames get their DidReflow() calls.
    DidReflowChildren(mFrames.FirstChild());
  }

  if (useMathMLChar) {
    // update our bounding metrics... it becomes that of our MathML char
    mBoundingMetrics = charSize;

    // if the returned direction is 'unsupported', the char didn't actually change. 
    // So we do the centering only if necessary
    if (mMathMLChar.GetStretchDirection() != NS_STRETCH_DIRECTION_UNSUPPORTED ||
        NS_MATHML_OPERATOR_IS_CENTERED(mFlags)) {

      bool largeopOnly =
        (NS_STRETCH_LARGEOP & stretchHint) != 0 &&
        (NS_STRETCH_VARIABLE_MASK & stretchHint) == 0;

      if (isVertical || NS_MATHML_OPERATOR_IS_CENTERED(mFlags)) {
        // the desired size returned by mMathMLChar maybe different
        // from the size of the container.
        // the mMathMLChar.mRect.y calculation is subtle, watch out!!!

        height = mBoundingMetrics.ascent + mBoundingMetrics.descent;
        if (NS_MATHML_OPERATOR_IS_SYMMETRIC(mFlags) ||
            NS_MATHML_OPERATOR_IS_CENTERED(mFlags)) {
          // For symmetric and vertical operators, or for operators that are always
          // centered ('+', '*', etc) we want to center about the axis of the container
          mBoundingMetrics.descent = height/2 - axisHeight;
        } else if (!largeopOnly) {
          // Align the center of the char with the center of the container
          mBoundingMetrics.descent = height/2 +
            (container.ascent + container.descent)/2 - container.ascent;
        } // else align the baselines
        mBoundingMetrics.ascent = height - mBoundingMetrics.descent;
      }
    }
  }

  // Fixup for the final height.
  // On one hand, our stretchy height can sometimes be shorter than surrounding
  // ASCII chars, e.g., arrow symbols have |mBoundingMetrics.ascent + leading|
  // that is smaller than the ASCII's ascent, hence when painting the background
  // later, it won't look uniform along the line.
  // On the other hand, sometimes we may leave too much gap when our glyph happens
  // to come from a font with tall glyphs. For example, since CMEX10 has very tall
  // glyphs, its natural font metrics are large, even if we pick a small glyph
  // whose size is comparable to the size of a normal ASCII glyph.
  // So to avoid uneven spacing in either of these two cases, we use the height
  // of the ASCII font as a reference and try to match it if possible.

  // special case for accents... keep them short to improve mouse operations...
  // an accent can only be the non-first child of <mover>, <munder>, <munderover>
  bool isAccent =
    NS_MATHML_EMBELLISH_IS_ACCENT(mEmbellishData.flags);
  if (isAccent) {
    nsEmbellishData parentData;
    GetEmbellishDataFrom(GetParent(), parentData);
    isAccent =
       (NS_MATHML_EMBELLISH_IS_ACCENTOVER(parentData.flags) ||
        NS_MATHML_EMBELLISH_IS_ACCENTUNDER(parentData.flags)) &&
       parentData.coreFrame != this;
  }
  if (isAccent && firstChild) {
    // see bug 188467 for what is going on here
    nscoord dy = aDesiredStretchSize.BlockStartAscent() -
      (mBoundingMetrics.ascent + leading);
    aDesiredStretchSize.SetBlockStartAscent(mBoundingMetrics.ascent + leading);
    aDesiredStretchSize.Height() = aDesiredStretchSize.BlockStartAscent() +
                                   mBoundingMetrics.descent;

    firstChild->SetPosition(firstChild->GetPosition() - nsPoint(0, dy));
  }
  else if (useMathMLChar) {
    nscoord ascent = fm->MaxAscent();
    nscoord descent = fm->MaxDescent();
    aDesiredStretchSize.SetBlockStartAscent(std::max(mBoundingMetrics.ascent + leading, ascent));
    aDesiredStretchSize.Height() = aDesiredStretchSize.BlockStartAscent() +
                                 std::max(mBoundingMetrics.descent + leading, descent);
  }
  aDesiredStretchSize.Width() = mBoundingMetrics.width;
  aDesiredStretchSize.mBoundingMetrics = mBoundingMetrics;
  mReference.x = 0;
  mReference.y = aDesiredStretchSize.BlockStartAscent();
  // Place our mMathMLChar, its origin is in our coordinate system
  if (useMathMLChar) {
    nscoord dy = aDesiredStretchSize.BlockStartAscent() - mBoundingMetrics.ascent;
    mMathMLChar.SetRect(nsRect(0, dy, charSize.width, charSize.ascent + charSize.descent));
  }

  // Before we leave... there is a last item in the check-list:
  // If our parent is not embellished, it means we are the outermost embellished
  // container and so we put the spacing, otherwise we don't include the spacing,
  // the outermost embellished container will take care of it.

  if (!NS_MATHML_OPERATOR_HAS_EMBELLISH_ANCESTOR(mFlags)) {

    // Account the spacing if we are not an accent with explicit attributes
    nscoord leadingSpace = mEmbellishData.leadingSpace;
    if (isAccent && !NS_MATHML_OPERATOR_HAS_LSPACE_ATTR(mFlags)) {
      leadingSpace = 0;
    }
    nscoord trailingSpace = mEmbellishData.trailingSpace;
    if (isAccent && !NS_MATHML_OPERATOR_HAS_RSPACE_ATTR(mFlags)) {
      trailingSpace = 0;
    }

    mBoundingMetrics.width += leadingSpace + trailingSpace;
    aDesiredStretchSize.Width() = mBoundingMetrics.width;
    aDesiredStretchSize.mBoundingMetrics.width = mBoundingMetrics.width;

    nscoord dx = (StyleVisibility()->mDirection ?
                  trailingSpace : leadingSpace);
    if (dx) {
      // adjust the offsets
      mBoundingMetrics.leftBearing += dx;
      mBoundingMetrics.rightBearing += dx;
      aDesiredStretchSize.mBoundingMetrics.leftBearing += dx;
      aDesiredStretchSize.mBoundingMetrics.rightBearing += dx;

      if (useMathMLChar) {
        nsRect rect;
        mMathMLChar.GetRect(rect);
        mMathMLChar.SetRect(nsRect(rect.x + dx, rect.y,
                                   rect.width, rect.height));
      }
      else {
        nsIFrame* childFrame = firstChild;
        while (childFrame) {
          childFrame->SetPosition(childFrame->GetPosition() +
                                  nsPoint(dx, 0));
          childFrame = childFrame->GetNextSibling();
        }
      }
    }
  }

  // Finished with these:
  ClearSavedChildMetrics();
  // Set our overflow area
  GatherAndStoreOverflow(&aDesiredStretchSize);

  // There used to be code here to change the height of the child frame to
  // change the caret height, but the text frame that manages the caret is now
  // not a direct child but wrapped in a block frame.  See also bug 412033.

  return NS_OK;
}

NS_IMETHODIMP
nsMathMLmoFrame::InheritAutomaticData(nsIFrame* aParent)
{
  // retain our native direction, it only changes if our text content changes
  nsStretchDirection direction = mEmbellishData.direction;
  nsMathMLTokenFrame::InheritAutomaticData(aParent);
  ProcessTextData();
  mEmbellishData.direction = direction;
  return NS_OK;
}

NS_IMETHODIMP
nsMathMLmoFrame::TransmitAutomaticData()
{
  // this will cause us to re-sync our flags from scratch
  // but our returned 'form' is still not final (bug 133429), it will
  // be recomputed to its final value during the next call in Reflow()
  mEmbellishData.coreFrame = nullptr;
  ProcessOperatorData();
  return NS_OK;
}

void
nsMathMLmoFrame::SetInitialChildList(ChildListID     aListID,
                                     nsFrameList&    aChildList)
{
  // First, let the parent class do its work
  nsMathMLTokenFrame::SetInitialChildList(aListID, aChildList);
  ProcessTextData();
}

void
nsMathMLmoFrame::Reflow(nsPresContext*          aPresContext,
                        ReflowOutput&     aDesiredSize,
                        const ReflowInput& aReflowInput,
                        nsReflowStatus&          aStatus)
{
  // certain values use units that depend on our style context, so
  // it is safer to just process the whole lot here
  ProcessOperatorData();

  nsMathMLTokenFrame::Reflow(aPresContext, aDesiredSize,
                             aReflowInput, aStatus);
}

nsresult
nsMathMLmoFrame::Place(DrawTarget*          aDrawTarget,
                       bool                 aPlaceOrigin,
                       ReflowOutput& aDesiredSize)
{
  nsresult rv = nsMathMLTokenFrame::Place(aDrawTarget, aPlaceOrigin, aDesiredSize);

  if (NS_FAILED(rv)) {
    return rv;
  }

  /* Special behaviour for largeops.
     In MathML "stretchy" and displaystyle "largeop" are different notions,
     even if we use the same technique to draw them (picking size variants).
     So largeop display operators should be considered "non-stretchy" and
     thus their sizes should be taken into account for the stretch size of
     other elements.

     This is a preliminary stretch - exact sizing/placement is handled by the
     Stretch() method.
  */

  if (!aPlaceOrigin &&
      StyleFont()->mMathDisplay == NS_MATHML_DISPLAYSTYLE_BLOCK &&
      NS_MATHML_OPERATOR_IS_LARGEOP(mFlags) && UseMathMLChar()) {
    nsBoundingMetrics newMetrics;
    rv = mMathMLChar.Stretch(PresContext(), aDrawTarget,
                             nsLayoutUtils::FontSizeInflationFor(this),
                             NS_STRETCH_DIRECTION_VERTICAL,
                             aDesiredSize.mBoundingMetrics, newMetrics,
                             NS_STRETCH_LARGEOP, StyleVisibility()->mDirection);

    if (NS_FAILED(rv)) {
      // Just use the initial size
      return NS_OK;
    }

    aDesiredSize.mBoundingMetrics = newMetrics;
     /* Treat the ascent/descent values calculated in the TokenFrame place
       calculations as the minimum for aDesiredSize calculations, rather
       than fetching them from font metrics again.
    */
    aDesiredSize.SetBlockStartAscent(std::max(mBoundingMetrics.ascent,
                                              newMetrics.ascent));
    aDesiredSize.Height() = aDesiredSize.BlockStartAscent() +
                            std::max(mBoundingMetrics.descent,
                                     newMetrics.descent);
    aDesiredSize.Width() = newMetrics.width;
    mBoundingMetrics = newMetrics;
  }
  return NS_OK;
}

/* virtual */ void
nsMathMLmoFrame::MarkIntrinsicISizesDirty()
{
  // if we get this, it may mean that something changed in the text
  // content. So blow away everything an re-build the automatic data
  // from the parent of our outermost embellished container (we ensure
  // that we are the core, not just a sibling of the core)

  ProcessTextData();

  nsIFrame* target = this;
  nsEmbellishData embellishData;
  do {
    target = target->GetParent();
    GetEmbellishDataFrom(target, embellishData);
  } while (embellishData.coreFrame == this);

  // we have automatic data to update in the children of the target frame
  // XXXldb This should really be marking dirty rather than rebuilding
  // so that we don't rebuild multiple times for the same change.
  RebuildAutomaticDataForChildren(target);

  nsMathMLContainerFrame::MarkIntrinsicISizesDirty();
}

/* virtual */ void
nsMathMLmoFrame::GetIntrinsicISizeMetrics(nsRenderingContext* aRenderingContext,
                                          ReflowOutput& aDesiredSize)
{
  ProcessOperatorData();
  if (UseMathMLChar()) {
    uint32_t stretchHint = GetStretchHint(mFlags, mPresentationData, true,
                                          StyleFont());
    aDesiredSize.Width() = mMathMLChar.
      GetMaxWidth(PresContext(), aRenderingContext->GetDrawTarget(),
                  nsLayoutUtils::FontSizeInflationFor(this),
                  stretchHint);
  }
  else {
    nsMathMLTokenFrame::GetIntrinsicISizeMetrics(aRenderingContext,
                                                 aDesiredSize);
  }

  // leadingSpace and trailingSpace are actually applied to the outermost
  // embellished container but for determining total intrinsic width it should
  // be safe to include it for the core here instead.
  bool isRTL = StyleVisibility()->mDirection;
  aDesiredSize.Width() +=
    mEmbellishData.leadingSpace + mEmbellishData.trailingSpace;
  aDesiredSize.mBoundingMetrics.width = aDesiredSize.Width();
  if (isRTL) {
    aDesiredSize.mBoundingMetrics.leftBearing += mEmbellishData.trailingSpace;
    aDesiredSize.mBoundingMetrics.rightBearing += mEmbellishData.trailingSpace;
  } else {
    aDesiredSize.mBoundingMetrics.leftBearing += mEmbellishData.leadingSpace;
    aDesiredSize.mBoundingMetrics.rightBearing += mEmbellishData.leadingSpace;
  }
}

nsresult
nsMathMLmoFrame::AttributeChanged(int32_t         aNameSpaceID,
                                  nsIAtom*        aAttribute,
                                  int32_t         aModType)
{
  // check if this is an attribute that can affect the embellished hierarchy
  // in a significant way and re-layout the entire hierarchy.
  if (nsGkAtoms::accent_ == aAttribute ||
      nsGkAtoms::movablelimits_ == aAttribute) {

    // set the target as the parent of our outermost embellished container
    // (we ensure that we are the core, not just a sibling of the core)
    nsIFrame* target = this;
    nsEmbellishData embellishData;
    do {
      target = target->GetParent();
      GetEmbellishDataFrom(target, embellishData);
    } while (embellishData.coreFrame == this);

    // we have automatic data to update in the children of the target frame
    return ReLayoutChildren(target);
  }

  return nsMathMLTokenFrame::
         AttributeChanged(aNameSpaceID, aAttribute, aModType);
}

// ----------------------
// No need to track the style context given to our MathML char. 
// the Style System will use these to pass the proper style context to our MathMLChar
nsStyleContext*
nsMathMLmoFrame::GetAdditionalStyleContext(int32_t aIndex) const
{
  switch (aIndex) {
  case NS_MATHML_CHAR_STYLE_CONTEXT_INDEX:
    return mMathMLChar.GetStyleContext();
  default:
    return nullptr;
  }
}

void
nsMathMLmoFrame::SetAdditionalStyleContext(int32_t          aIndex,
                                           nsStyleContext*  aStyleContext)
{
  switch (aIndex) {
  case NS_MATHML_CHAR_STYLE_CONTEXT_INDEX:
    mMathMLChar.SetStyleContext(aStyleContext);
    break;
  }
}